Publishing type：Research paper (scientific journal)   Publisher：Japanese Society for Horticultural Science  

DOI： 10.2503/hrj.21.65

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Inflammation is the cause and/or result of many diseases in peripheral tissues and the central nervous system. Recent findings suggested that inflammation in peripheral tissue induces an inflammatory response in the brain that activates glial cells, which, in turn, induce neuronal cell dysfunction. Therefore, anti-inflammatory compounds are important for the suppression of chronic inflammation and prevention of disease. The present study revealed microglial activation in the hippocampus of the brain two days after the peripheral administration of lipopolysaccharide (LPS). Furthermore, the expression of the synaptic vesicle membrane protein, synaptophysin, in the CA3 stratum lucidum of the hippocampus was down-regulated 7 days after the LPS injection. The administration of tocotrienols, a type of vitamin E, significantly attenuated these changes in the hippocampus. Collectively, the present results demonstrated the spread of peripheral inflammatory responses to the brain, in which glial activation and neuronal dysfunction were induced, while tocotrienols exerted anti-inflammatory effects and protected neurons from damage.

DOI： 10.3390/neuroglia2010009

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

<title>Abstract</title>High night temperature (HNT) often reduces yield in field crops. In rice, HNT during the ripening stage diminishes endosperm cell size, resulting in a considerable reduction in final kernel weight; however, little is known about the underlying mechanisms at cell level. In this study, we performed picolitre pressure-probe-electrospray-ionization mass spectrometry to directly determine metabolites in growing inner endosperm cells of intact seeds produced under HNT conditions, combining with ¹³C feeding and water status measurements including in situ turgor assay. Microscopic observation in the inner zone suggested that approximately 24.2% of decrease in cell expansion rate occurred under HNT at early ripening stage, leading to a reduction in cell volume. It has been shown that HNT-treated plants were subjected to mild shoot water deficit at night and endosperm cell turgor was sustained by a decline in osmotic potential. Cell metabolomics also suggests that active solute accumulation was caused by a partial inhibition of wall and starch biosynthesis under HNT conditions. Because metabolites were detected in the single cells, it is concluded that a partial arrest of cell expansion observed in the inner endosperms was caused by osmotic adjustment at mild water deficit during HNT conditions.

DOI： 10.1038/s41598-021-83870-1

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Other Link： http://www.nature.com/articles/s41598-021-83870-1

Language：Japanese   Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

High night temperature (HNT) at the ripening stage severely affects both rice yield and quality. HNT accelerates embryo growth and chalky formation in the developing grains, accompanying with a diminishment of endosperm cell size. Although these responses may be physiologically interacted each other in the grains, what signals are involved in the accelerated embryo development remains undetermined. In this work, we have used picolitre pressure-probe electrospray-ionization mass spectrometry (picoPPESI-MS) to conduct single-cell metabolomics at several regions in HNT-treated grains, embryonic scutellum and outer endosperms in the basal ('chalky region' at maturation) and middle ('translucent region' at maturation as a reference) positions. Microscopic observations showed that HNT promoted cell expansion rate in the scutellum. When embryonic cell expansion rate reached the maximum, spatial differences in several metabolisms including ascorbate-glutathione (ASC-GSH) pathway and purine were detected, together with considerable sugar and amino acid accumulations in embryonic scutellum cells. There was no treatment difference in GSH content during active cell expansion in HNT-treated embryos, although an increase in GSH/GSSG ratio due to a reduction in oxidized glutathione (GSSG) content has been contrastingly observed. In the endosperms, greater ASC accumulation with a difference in ASC/dehydroascobic acid ratio has been also detected under HNT conditions. Since dormancy is often correlated with GSSG concentration, it is concluded that spatial regulation of GSH redox homeostasis detected at cell-level might be essential for dormancy alleviation and embryo growth accelerated in HNT-treated seeds.

DOI： 10.1016/j.envexpbot.2021.104515

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Publishing type：Research paper (scientific journal)   Publisher：Japanese Society for Horticultural Science  

DOI： 10.2503/hrj.20.95

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Language：English   Publishing type：Research paper (scientific journal)  

To further develop barley breeding and genetics, more information on gene functions based on the analysis of the mutants of each gene is needed. However, the mutant resources are not as well developed as the model plants, such as Arabidopsis and rice. Although genome editing techniques have been able to generate mutants, it is not yet an effective method as it can only be used to transform a limited number of cultivars. Here, we developed a mutant population using 'Mannenboshi', which produces good quality grains with high yields but is susceptible to disease, to establish a Targeting Induced Local Lesions IN Genomes (TILLING) system that can isolate mutants in a high-throughput manner. To evaluate the availability of the prepared 8043 M3 lines, we investigated the frequency of mutant occurrence using a rapid, visually detectable waxy phenotype as an indicator. Four mutants were isolated and single nucleotide polymorphisms (SNPs) were identified in the Waxy gene as novel alleles. It was confirmed that the mutations could be easily detected using the mismatch endonuclease CELI, revealing that a sufficient number of mutants could be rapidly isolated from our TILLING population.

DOI： 10.3390/plants9091153

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Language：Japanese   Publishing type：Research paper (scientific journal)  

J-GLOBAL

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：FRONTIERS MEDIA SA  

In protected strawberry (Fragaria x ananassa Duch.) cultivation, environmental control based on the process of photosynthate translocation is essential for optimizing fruit quality and yield, because the process of photosynthate translocation directly affects dry matter partitioning. We visualized photosynthate translocation to strawberry fruits non-invasively with (CO2)-C-11 and a positron-emitting tracer imaging system (PETIS). We used PETIS to evaluate real-time dynamics of C-11-labeled photosynthate translocation from a (CO2)-C-1-C-1-fed leaf, which was immediately below the inflorescence, to individual fruits on an inflorescence in intact plant. Serial photosynthate translocation images and animations obtained by PETIS verified that the C-11-photosynthates from the source leaf reached the sink fruit within 1 h but did not accumulate homogeneously within a fruit. The quantity of photosynthate translocation as represented by C-11 radioactivity varied among individual fruits and their positions on the inflorescence. Photosynthate translocation rates to secondary fruit were faster than those to primary or tertiary fruits, even though the translocation pathway from leaf to fruit was the longest for the secondary fruit. Moreover, the secondary fruit was 25% smaller than the primary fruit. Sink activity (C-11 radioactivity/dry weight [DW]) of the secondary fruit was higher than those of the primary and tertiary fruits. These relative differences in sink activity levels among the three fruit positions were also confirmed by C-13 tracer measurement. Photosynthate translocation rates in the pedicels might be dependent on the sink strength of the adjoining fruits. The present study established C-11-photosynthate arrival times to the sink fruits and demonstrated that the translocated material does not uniformly accumulate within a fruit. The actual quantities of translocated photosynthates from a specific leaf differed among individual fruits on the same inflorescence. To the best of our knowledge, this is the first reported observation of real-time translocation to individual fruits in an intact strawberry plant using C-11-radioactive- and C-13-stable-isotope analyses.

DOI： 10.3389/fpls.2018.01946

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Language：English   Publisher：SPRINGER  

Background: High water use efficiency is essential to water-saving cropping. Morphological traits that affect photosynthetic water use efficiency are not well known. We examined whether leaf hairiness improves photosynthetic water use efficiency in rice.
Results: A chromosome segment introgression line (IL-hairy) of wild Oryza nivara (Acc. IRGC105715) with the genetic background of Oryza sativa cultivar 'IR24' had high leaf pubescence (hair). The leaf hairs developed along small vascular bundles. Linkage analysis in BC5F2 and F-3 populations showed that the trait was governed by a single gene, designated BLANKET LEAF (BKL), on chromosome 6. IL-hairy plants had a warmer leaf surface in sunlight, probably due to increased boundary layer resistance. They had a lower transpiration rate under moderate and high light intensities, resulting in higher photosynthetic water use efficiency.
Conclusion: Introgression of BKL on chromosome 6 from O. nivara improved photosynthetic water use efficiency in the genetic background of IR24.

DOI： 10.1186/s12284-017-0158-1

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Language：Japanese   Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.244.0_103

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Language：Japanese   Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.244.0_77

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Language：Japanese   Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.244.0_78

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Crop Science Society of Japan  

An effective fertilizer system is required to achieve high and stable grain protein levels in the wheat cultivar “ChikushiW2” for Chinese noodles. In this study, we examined the fertilizer nitrogen utilization rate (FNU), grain nitrogen content, nitrogen contribution ratio (NCR) of nitrogen fertilizer, and nitrogen fertility using 15N-labeled ammonium sulfate in “ChikushiW2” to determine the nitrogen kinetics in wheat plants. At the early-ripening stage, nitrogen was distributed within the range 78-83% in foliage and 17-22% in grain. Nitrogen translocated from foliage to grain during the middle-ripening stage, with a final grain accumulation of 87-89% of the nitrogen at the late-ripening stage. FNU of the basal dressing was the lowest at 15-20%, increasing to 37-56% for the topdressing at tillering stage with annual variation, and highest at 67-74% for the topdressing at the panicle formation stage and the topdressing at full heading. NCR in the grain nitrogen content was lowest at 4-7% for basal dressing, 10-14% for the topdressing at the tillering stage and topdressing at the panicle formation stage, 24-30% for the topdressing at full heading, and highest at 41-49% for nitrogen fertility. These results indicate that reducing the quantity of low FNU basal dressing, reducing the variable FNU on the topdressing at the tillering stage, and adjusting the timing and quantity of fertilizer application on the high-FNU topdressing at the panicle formation stage, may be effective in enhancing and stabilizing the grain protein content.

DOI： 10.1626/jcs.85.385

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Language：Japanese   Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.241.0_64

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Language：Japanese   Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.241.0_86

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Language：Japanese   Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.241.0_63

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Language：Japanese   Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.241.0_65

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Language：Japanese   Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.241.0_180

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Language：Japanese  

CiNii Books

J-GLOBAL

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Language：Japanese   Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.240.0_119

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Crop Science Society of Japan  

We examined the nitrogen topdressing timing &lt
sup&gt
15&lt
/sup&gt
N labeled ammonium sulfate for increasing grain protein content above 12% in the wheat cultivar for Chinese noodles ‘ChikushiW2gou’. The topdressing at the full heading and 7 days later stably increased grain protein content above 12% regardless of the year. Also the number of days from full heading to topdressing correlated negatively with the ratio of nitrogen content of ripe grain derived from topdressing to topdressing nitrogen amount (nitrogen availability) and total nitrogen contents in ripe grain (nitrogen contribution ratio). Topdressing at full heading or 7 days later resulted in almost 60% of the nitrogen availability and 30% of nitrogen contribution ratio. The nitrogen availability in topdressing at 14 days after full heading time was affected by the rain after the topdressing. Topdressing at 21 or 28 days after heading hardly contributed to protein accumulation, resulting in a protein content of ripe grain of less than 12%. In this study, we concluded that the appropriate time of nitrogen topdressing for increasing grain protein content above 12% in “ChikushiW2gou” is from full heading to 7 days later, where the availability of topdressed nitrogen is more than 60% and the contribution ratio of topdressed nitrogen to grain protein is above 30%.

DOI： 10.1626/jcs.84.155

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Rice is believed to show photosynthetic symmetry between adaxial and abaxial leaf sides. To verify this, we re-examined dorsoventral asymmetry in photosynthesis, chlorophyll fluorescence and anatomical traits in flag leaves of two Oryza sativa cultivars that differ in nitrogen (N) response and in leaf angle: 'Akenohoshi', a cultivar that can adapt to low-N (LN), with low leaf angle (more erect leaves), and 'Shirobeniya', a cultivar that is unable to adapt to LN, with higher leaf angle. Plants were grown under standard-N (SN) and LN conditions. LN leaves of both cultivars became more erect than SN, but LN Akenohoshi still had more erect ones than Shirobeniya. Contrary to results of previous studies, leaves of both cultivars showed an asymmetry in photosynthetic rate between adaxial and abaxial sides (higher on the adaxial side) under SN. SN leaves of both cultivars showed lower susceptibility to photoinhibition on the adaxial side than on the abaxial side. However, leaves of Akenohoshi showed less asymmetry in these traits under LN than under SN, whereas leaves of Shirobeniya had similar degrees of asymmetry in these traits under both SN and LN. Both cultivars also showed dorsoventral asymmetry in anatomical traits of mesophyll tissue regardless of N level, but the degree of asymmetry was lower in LN Akenohoshi. These data reveal that rice leaves exhibit dorsoventral asymmetry in photosynthetic and anatomical features, and that the degree of asymmetry varies with cultivar and N level. It is suggested that lower leaf angles (particularly in Akenohoshi) in the presence of LN represent a light acclimation to prevent photoinhibition.

DOI： 10.1111/ppl.12145

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

Heterosis is defined as increased vigour of hybrids in comparison to their parents. In this study, seven cultivars of upland inbred rice (male parents) and their F-1 hybrids generated by crossing with a thermo-sensitive genic male sterile (TGMS) 103(s) line (female parent). The cultivars were examined for characters of photosynthesis and dry matter production under drought stress at flowering stage and recovery at ripening stage. The results showed that under drought, all F-1 hybrids exhibited very low negative heterosis for CO2 exchange rate, stomatal conductance, mesophyll conductance and transpiration rate, but high positive heterosis for intercellular CO2 concentration. The heterosis value increased much more in the F-1 hybrids under drought recovery than under well water conditions. During drought stress, heterosis value decreased slightly for dry matter accumulation compared to well irrigated conditions. Although CO2 exchange rate significantly decreased, dry matter accumulation was maintained in all F-1 hybrids after drought recovery, which suggests the potential for using upland rice as male parent to produce F-1 hybrids from TGMS lines for drought tolerance.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

An F-1 hybrid rice combination from a cross between a thermo-sensitive genic male sterility (TGMS) '103S' line and an upland rice 'IR17525' were investigated for physiological response traits under drought stress and recovery at the heading time by comparing with its parents. The F-1 and parental plants were planted in pots in a net house at different times for synchronizing flowering. At the stage of 5-3 days before heading, water was withdrawn from the pot. When the soil water potential in the pot reached -60 kPa, photosynthetic rate and dry matter accumulation were measured. Recovery traits including photosynthetic rate and dry weight of panicle were measured at 5 days interval until harvesting. The results showed that the photbsynthetic rate was lower in the F-1 hybrid than that in the parents during drought treatment, in contrary it. was higher during recovery stage. The grain yield was maintained in the F-1 hybrid under drought; treatment as much as under the control condition, whereas it significantly reduced as drought treatment in the male, parent. The grain yield was higher in the F-1 hybrid than that in the male parent under the well, irrigated condition, and even much higher under drought treatment. It is suggested that such advantageous characters, including the shorter ripening duration, the longer panicle exertion, the higher recovery photo. synthetic rate as well in the faster of dry matter translocation into panicle at the ripening stage, contribute;drought tolerance in rice. Thus, the F-1 hybrid rice 103S/IR17525 would be a promising rice with high yield potential under drought stress.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Biotron Institute  

In this study, we discussed how temperature and other environmental factors affect the fruit growth and quality of Satsuma mandarin grown in a plastic house with heating. At 14-23°C, the average nighttime air temperature was positively correlated with the standardized fruit growth rale (GRFSt) in the young stage, in contrast, GRFStwas clearly depressed with a daytime air temperature at around 30°C, and the optimum air temperature for active fruit growth was 25°C. Moreover, in the middle and mature stages, the air temperature did not correlate with the GRFst. These results indicate that, in the young stage, the air temperature should be controlled at around 25°C during the daytime and 20-23°C during the nighttime for active fruit growth. In the middle and mature stages, fruit growth might not require nighttime air temperatures that are as high as 20-23°C. The air temperatures did not correlate with the fruit soluble sugar content (SSC)
in contrast, a close relationship was found between the predawn xylem water potential (ΨXy) and SSC. The day temperature, radiation and ΨXywere linearly correlated with the fruit titratabie acidity (TA) in the young stage.

DOI： 10.2525/ecb.52.161

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Language：Japanese   Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.238.0_78

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Biotron Institute  

The aim of this study was to determine the optimum photoperiod of supplemental lighting to obtain high fruit yields in forcing culture of strawberry. Strawberry plants were illuminated with supplemental lighting provided by high-irradiance light-emitting diodes with photoperiods of 24, 16, 14, or 12-h daily under the controlled air temperature conditions set the ventilation starting temperature at 26°C and minimum air temperature at 6°C from October to May. Compared with plants in the other treatments and the control, those in the 12-h photoperiod treatment showed a significant increase in leaf photosynthesis and earlier differentiation of flower buds on the second inflorescence. These physiological changes resulted in the large amounts of carbon translocation from leaf to fruit, leading to the fruit quality improvement and the highest marketable yield among all of the treatments. When the photoperiod of supplemental lighting exceeded 12 h per day, flower opening on the first inflorescence was accelerated, but flower bud initiation on the second inflorescence was inhibited. This inhibition caused a decrease in leaf photosynthesis, leading to excessive carbohydrate accumulation in the leaves, resulting in lower total fruit yield than that from plants in the 12-h photoperiod treatment. These data show that a 12-h photoperiod of supplemental lighting is appropriate to obtain high yields in forcing culture of strawberry.

DOI： 10.2525/ecb.52.63

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Biotron Institute  

The response in growth and gas exchange to a flooding condition was characterized with 8 cultivars of greengram (Vigna radiata (L.) Wilczek). Pot-grown plants were subjected to 6-d flooding and 6-d recovery treatment. The flooding treatment had serious effects on the gas exchange and electron transport of 7 cultivars except for cv. KP, while the damages were lenient in cv. KP. KP was characterized by maintaining relatively higher stomatal conductance, mesophyll conductance and photochemical efficiency of photosystem II, which was attributed to sustaining the CO2 assimilation under flooding stress. KP was also superior in photosynthetic sustainment than other 7 cultivars under recovery treatment, which was attributable to the fact that this cultivar recovered stomatal conductance, mesophyll conductance, electron transport and the ratio of photorespiration to total carbon assimilation. These results in cv. KP lead to higher plant growth in relation to leaf area extension and dry matter.

DOI： 10.2525/ecb.52.1

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Biotron Institute  

The effects of shading on growth and photosynthetic potential was analyzed with 8 cultivars with greengram (Vigna radiata (L.) Wilczek). Plants grown in 5 L pots were subjected to 2-week shading treatment and after 2-week recovery by removing a black-cheese cloth. Photosynthetic potential was evaluated by electron transport rate sealed on the both leaf surfaces by vaseline, which is close relationship to gross photosynthetic rate because CO2 released by the reaction of photorespiration is recycled by stroma in chloroplast. Shading treatment reduced total dry weight of all cultivars. In particular, significant reduction in total dry weight was found in Nyangoo, Magwe and VC. Leaf specific area under shading treatment showed increment tendency and remarkable increase in this parameter was found in Nyangoo and VC, which cultivars decreased total dry weight under shading, indicating that shading treatment lead to thin of the leaf thickness. The ratio of plant height to diameter of stem was significantly decreased in R-288-8, Kanti and Yezin-5 by shading, indicating the restriction of succulent growth under shading condition and these cultivars are superior in lodging resistance to other cultivars. Photosynthetic rate as evaluated by electron transport rate sealed by vaseline was decreased by shading treatment. The extent of decrease in photosynthetic potential was found cultivaral difference. According to these results, Kanti is capable of applicable to the highest in resistance to shading and its recovery.

DOI： 10.2525/ecb.52.227

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Biotron Institute  

In order to clarify the effect of nighttime temperatures on fruit development of Satsuma mandarin, we examined the fruit water and carbon balances using the 13C tracer method and the roles of phloem and xylem transports for fruit growth under moderate night temperatures (MN, set at 23°C) and low night temperatures (LN, set at 13°C). The average predawn xylem water potentials were -0.79 ± 0.04 MPa under MN and -0.77±0.03 MPa under LN. Fruit growth used 86% of pedicel sap flux toward the fruit, while transpiratory water losses from the fruit surface were 14% of pedicel sap flux under both MN and LN. The daytime integrated xylem sap flux was negative, but it was positive in the nighttime. The integrated phloem sap flux (ΣJPhlo) and the difference in ΣJPhlo, between MN and LN were only' 6-10% and 4% of the total sap accumulated in the fruit, respectively. Integrated fruit photosynthesis and integrated CO2efflux from the fruit surface were 7-8% and 22-23% of the total carbon supply toward the fruit, respectively. This indicates that carbon translocation from leaves to fruit via the phloem of the stem is the main source of carbon for the fruit.

DOI： 10.2525/ecb.52.167

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Biotron Institute  

In order to control nighttime temperatures with energy saving, how different night temperature regimes affected on the fruit growth, quality and 13C allocation from leaf to fruit were researched by both the partial heating and whole tree heating. One type, altering time of nighttime heating, the end of day (EOD) -heating, middle of night (MON) -heating, and predawn (Pd) -heating were applied. The EOD-heating temporally activated the fruit growth and accelerated the 13C allocation from leaf to fruit through short term (hours) researches by the partial heating, however, comparing to the conventional heating as 20°C constant in nighttime by the whole tree heating during 60-90 days after full bloom (DAFB), no superiority was observed in both the fruit volume increase and fruit quality, and the MON-heating showed the depression of fruit growth. Another type of a regime determined by daily integrated solar radiation, comparing to the conventional heating as 17°C constant in nighttime during 78-120 DAFB, no superiority was observed in the fruit quality. Nighttime 13C allocation from the leaf to fruit was detected at 90 DAFB, though was hardly detected at all at 120 DAFB regardless of night temperatures as high as 25°C at both days.

DOI： 10.2525/ecb.52.175

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Language：English   Publishing type：Part of collection (book)   Publisher：Springer  

The function of foliar betacyanin as a photoprotective mechanism in water stressed Amaranthus cruentus plants was examined by comparing leaves of two strains differing significantly in betacyanin accumulation. Drought treatment was imposed by withholding irrigation for 2 days and at 0, 1, and 2 days after treatment onset, leaves were subjected to high light (HL) treatment to assess their tolerability to photoinhibition. The drought treatment reduced relative water content and gas exchange rate to similar extent in both strains. As drought developed, the extent of photoinhibition after HL treatment increased in both strains, however, it was significantly greater in acyanic than in betacyanic strains, indicating higher tolerance of betacyanic leaves to photoinhibition. The betacyanic leaves also exhibited higher values for quantum yield of PSII (ΦPSII) and photochemical quenching (qP) during drought treatment despite the non-photochemical quenching (qN) did not differ between strains. These results may be partially explained by light screening effect of foliar betacyanin. Moreover, the increased betacyanin and decreased chlorophyll contents in betacyanic leaves were thought to have enhanced effectiveness of photoprotection provided by betacyanin during the drought period. Our results demonstrated the potential protective function of foliar betacyanin against photoinhibition in A. cruentus under drought conditions.

DOI： 10.1007/978-3-642-32034-7_102

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Publishing type：Research paper (international conference proceedings)  

In production of Satsuma mandarin (Citrus unshiu Marc.) grown on greenhouse cultivation, management of day and night temperature and soil water content is important to improve yield and quality of the fruits. In this study, in order to optimize greenhouse environment for Satsuma mandarin production, we conducted dynamic analysis of effects of soil water content, day temperature and night temperatures on fruit growth and mass accumulation through phloem and xylem into a fruit.

DOI： 10.3182/20130327-3-jp-3017.00068

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Crop Science Society of Japan  

To clarify the genotypic variation of nitrogen (N) response in the AA genome Oryza species, we investigated dry matter production, N uptake, N and water use efficiencies (NUE and WUE), bleeding sap rate (BR), and root morphological traits at vegetative stage in 6 cultivars and 4 strains of 6 species (O. sativa, O. glaberrima, O. barthii, O. nivara, O. meridionalis, and O. rufpogon) grown under standard N (SN) and low N (LN) conditions. Some wild Oryza strains and O. glaberrima showed high dry matter production under both N conditions. In most plants, total dry weight decreased and root dry weight increased under the LN condition, resulting in decreased top-root ratio. In japonica cultivars of O. sativa, however, these traits were unaffected by the N condition. There were no significant differences in WUE with plant species or N conditions. In all plants, however, NUE was higher in the LN than SN condition, and was conspicuously high in most wild Oryza species and O. glaberrima. Some of them showed increased capacity of nitrate-N (NO3-N) uptake under the LN condition. In cultivars and strains with a high NUE, root dry weight, root surface area, and BR were also higher under the LN condition. These results suggest that a high NUE is associated with the development of a root system, increased BR, and probably increased capacity of NO3-N uptake. This study revealed the presence of superior wild Oryza strains for growth under LN that may be a promising genetic resource for low N-input agriculture.

DOI： 10.1626/pps.16.107

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Language：English   Publishing type：Research paper (scientific journal)  

Light condition is a fundamental environmental factor for high-quality plant production. In this paper, we discuss how light condition affects fruit development in the long and short term, and attempt to clarify management methods for active fruit development under conditions of low solar radiation, by using quantitative research on fruit water and carbon balance during greenhouse cultivation of Satsuma mandarin (Citrus unshiu Marc.). A significant decrease in yield due to shading was not detected, but we confirmed that shading treatment affected the dry weights of source-sink units, fruit volume, increase in volume of the fruits, and fruit quality parameters, such as sugar accumulation, acid content, and rind color. Qualitatively, the carbon balance of Satsuma mandarin fruit is comparable to that of tomato fruit or rice panicle, but quantitatively, the carbon balance of Satsuma mandarin fruit may differ, as shown by low sink relative growth rate. In addition, fruit growth parameters such as translocation rate for a fruit and fruit relative growth rate showed significant positive correlations with dark respiration, despite the shading treatment. The fruit carbon demand may be simply described by fruit dark respiration as the sum of new photosynthetic carbon and stored carbon translocation for a fruit.

DOI： 10.2525/ecb.51.49

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：生態工学会  

A cropped soil column system was used to analyze water and ion dynamics in soil affected by root absorptive functions of different crop species. The respective soil columns were cropped with corn, sunflowers, beets, and frog-fruits (i.e. cover grass), where the salinized groundwater was supplied as found in the salinized crop fields under desertification. In the corn and sunflower columns, the increased transpiration of leaves and decreased Na&lt;sup&gt;+&lt;/sup&gt; and Cl&lt;sup&gt;-&lt;/sup&gt; absorbing Power of roots resulted in increased salt accumulation in the soil, while the major essential ions of NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;, PO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;3-&lt;/sup&gt; and K&lt;sup&gt;+&lt;/sup&gt; were actively absorbed by roots and scarcely remained in the soil. In the beet and frog-fruit columns, it was considered that transpiration was low compared with the corn and sunflower columns and also soil surface evaporation was depressed by leaves growing horizontally over the soil surface. Furthermore, beet roots showed uniquely high Na&lt;sup&gt;+&lt;/sup&gt; and Cl&lt;sup&gt;-&lt;/sup&gt; absorbing power. These factors resulted in decreased salt accumulation in the soil of the beet and frog-fruit columns. The lowest salt accumulation occurred in the no-crop column (without leaf transpiration and root absorptive functions). These results demonstrated that the transpiration, active and selective ion absorption, and leaf morphology of different plant species have a large influence on the amount and composition of ions accumulated in the soil.

DOI： 10.11450/seitaikogaku.24.69

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Language：Japanese   Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.233.0.250.0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

Vietlai 45 (VL45) is F-1 hybrid rice that has been recently introduced in Vietnam. Despite its high yield potential, the grown period is about two weeks shorter than the parents. To elucidate the factor resulting in this superior trait, we investigated photosynthetic traits in upper three leaves including the flag leaf (FL) during the ripening period in VL45 in comparison with its female and male parents, 103S and R45. At 3 days after heading (DAH), shoot dry weight was higher in VL45 than in the parent cultivars, whereas the leaf morphological traits of VL45 were similar to those of R45. The nitrogen content in leaves tended to be higher in VL45 than in R45 at 14 DAH. At 24 DAH, the FL of VL45 showed higher net photosynthetic rate (P-n) and stomatal conductance (G(s)) than those of the parents, with a symptom of senescence in other leaves. Values of chlorophyll fluorescence parameters did not greatly differ among the three cultivars. P-n per unit soluble protein content (P-n/SP) in the FL was much higher in VL45 than in the parents at 24 DAH. Thus, it seems that higher P-n the FL of VL45 is because of high G(s) and P-n/SP. These data demonstrate that VL45 shows the heterosis effect on the dry matter production until heading and the maintenance of high P-n in the FL at late ripening stage, which would contribute to the superior agronomic trait of VL45.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

Effects of limited nitrogen (N) supply on dry matter and grain productions were investigated in the pot-grown six rice cultivars, Kasalath (a traditional indica), 11136 (an improved indica), Shirobeniya (a conventional japonica), Nipponbare (an improved japonica), BSI429 (an improved tropical japonica, a new plant type line) and Akenohoshi (an improved japonica-indica cross). At maturity, N limitation caused significant decreases in aboveground dry weight (DW), DW increased during heading to maturity (Delta DW), grain weight, panicle number per plant, fertility % and sink size in the six cultivars, and there were significant "cultivar x N" interactions; the magnitudes of these decreases caused by limited N supply were smallest M Akenohoshi. There were significant positive correlations between grain weight and aboveground DW at maturity under both standard-N (SN) and low-N (LN) conditions, whereas there was a significant positive correlation between grain weight and Delta DW under the LN condition but not under the SN condition. Grain weight was more closely correlated with sink size under both N conditions. Among the cultivars examined, Akenohoshi showed the highest Delta DW, fertility % and sink size wider the LN condition, leading the highest grain weight. It is suggested that Akenohoshi is a breeding material useful for the improvement of adaptability to LN environment.

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In order to improve temperature and water management in the greenhouse cultivation of Satsuma mandarins, short-term water and carbon balance in intact Satsuma mandarin fruits was studied by measuring fruit expansive growth, CO 2 and H 2O gas exchange, sap flux into the fruit through the phloem and xylem, and 13C partitioning. Seventy-one days after full bloom, with day/night temperature set at 28°C/23°C and under fine weather conditions, sap flux through the xylem into the fruit showed a dynamic diurnal change which was related to changes of fruit volume. In leaves, 13C partitioning decreased from 11:00 until 23:00, remaining constant thereafter, whereas in fruits, 13C partitioning increased from 11:00 until 23:00, and then remained contrast. Investigating the cumulative water balance, 19% of water output was lost by fruit transpiration, whereas 81% contributed to fruit growth. In cumulative carbon balance, 39% of carbon output was lost by fruit respiration, whereas 61% contributed to fruit growth. Quantitative analyses of physiological responses to environmental conditions, as measured in this study, are essential for establishing energy-saving temperature management strategies.

DOI： 10.2525/ecb.50.189

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The response in gas exchange and photosystem II (PSII) functions to a flooding condition was characterized with kenaf (Hibiscus cannabinus) by comparing it with napiergrass (Pennisetum purpureum, Ci-plant), corn (Zea mays, Ci-plant) and mungbean (Vigna radiata, C3-plant). Pot-grown plants were subjected to a 1-week flooding and a 1-week recovery treatment. The flooding treatment had serious effects on the gas exchange of mungbean and corn, while the damages were lenient in kenaf and napiergrass. Kenaf and napiergrass were characterized by keeping a higher stomatal conductance (G,) and mesophyll conductance (Gm), which resulted in sustaining the CO2 assimilation under the flooding stress condition. As compared between these two high-yielding species, kenaf was superior in photosynthetic sustainment than napiergrass under the flooding and recovery treatments. The superiority in kenaf is attributable to the fact that this species keeps higher G, under the flooding, by which photosynthesis was able to continue, and the photosynthetic apparatus prevents the excessive energy accumulation in the leaf. Also, kenaf showed the increase photorespiration and non-photochemical quenching (NPQ) during the treatments.

DOI： 10.2525/ecb.50.127

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Chlorophyll (Chi) fluorescence measured on a leaf surface only provides the photosynthetic status of chloroplasts near the surface due to self-shading effect of Chi. Here, we report a laser-induced Chi fluorescence measurement system, which enables measurement of fluorescence induction kinetics at different tissues within a leaf as well as on both leaf surfaces, to assess photosynthetic status within leaves. The logarithmic time-scaled Chi fluorescence induction kinetics obtained from Chenopodium album leaves showed polyphasic transients in which four inflection points designated as O, J, I and P, were observed. Adaxial surface and palisade mesophyll showed significantly higher fluorescence intensities at O than abaxial surface and spongy mesophyll, respectively. In contrast, fluorescence intensities at J, I and P were significantly higher at abaxial surface and spongy mesophyll. Using these fluorescence intensities, the JIP test was performed. The results of JIP test indicated that adaxial surface and palisade mesophyll are characterized by lower maximum quantum yield of photosystem II (PSII) and net rate of PSII closure, but higher rate of energy transfer into electron transport chain than abaxial surface and spongy mesophyll. Considering these dorsiventral and intra-leaf variations in Chi fluorescence parameters, this study suggested the necessity of Chi fluorescence measurements on tissues as well as both surfaces to evaluate photosynthetic status of a whole leaf.

DOI： 10.2525/ecb.50.91

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

The photoprotective function of leaf betacyanin in water-stressed Amaranthus cruentus plants was examined by comparing leaves of two strains which differ significantly in the amount of betacyanin. At 0, 1, and 2 days after the imposed water stress, leaves were subjected to high-light (HL) treatment to assess their photosynthetic capacity and photoinhibition susceptibility. The water stress equally reduced leaf relative water content (RWC), gas-exchange rate and chlorophyll (Chl) contents in both leaves, indicating that the severity of water stress was comparable between the strains. Consequently, the extent of photoinhibition after the HL treatment increased in both strains as water stress developed; however, it was significantly greater in acyanic leaves than in betacyanic leaves, suggesting lower photoinhibition susceptibility in the betacyanic strain. The betacyanic leaves also exhibited approximately 30% higher values for photochemical quenching coefficient (q(P)) during the period of water stress despite the nonphotochemical quenching coefficient (q(N)) did not differ significantly between the strains. These results may be partially explained by the increased amount of leaf betacyanin under water stress. Moreover, a decrease in Chl content in betacyanic leaves might have enhanced light screening effect of betacyanin by increasing relative abundance of betacyanin to Chl molecule. In addition, reduced Chl content increased light penetrability of leaves. As a result, the extent of photoinhibition at the deeper tissue was exacerbated and the Chl fluorescence emitted from these tissues was more readily detected, facilitating assessment of photoinhibition at deeper tissues where the effect of betacyanic light screening is considered to be most apparent. Our results demonstrated that leaf betacyanin contributes to total photoprotective capacity of A. cruentus leaves by lowering excitation pressure on photosystem II (PSII) via attenuation of potentially harmful excess incident light under water stress.

DOI： 10.1007/s11099-011-0062-7

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：OXFORD UNIV PRESS  

Background and Aims Rice (Oryza sativa) plants lose significant amounts of volatile NH(3) from their leaves, but it has not been shown that this is a consequence of photorespiration. Involvement of photorespiration in NH(3) emission and the role of glutamine synthetase (GS) on NH(3) recycling were investigated using two rice cultivars with different GS activities.
Methods NH(3) emission (AER), and gross photosynthesis (P(G)), transpiration (Tr) and stomatal conductance (g(S)) were measured on leaves of &apos;Akenohoshi&apos;, a cultivar with high GS activity, and &apos;Kasalath&apos;, a cultivar with low GS activity, under different light intensities (200, 500 and 1000 mu mol m(-2) s(-1)), leaf temperatures (27.5, 32.5 and 37.5 degrees C) and atmospheric O(2) concentrations ([O(2)]: 2, 21 and 40%, corresponding to 20, 210 and 400 mmol mol(-1)).
Key Results An increase in [O(2)] increased AER in the two cultivars, accompanied by a decrease in P(G) due to enhanced photorespiration, but did not greatly influence Tr and g(S). There were significant positive correlations between AER and photorespiration in both cultivars. Increasing light intensity increased AER, P(G), Tr and g(S) in both cultivars, whereas increasing leaf temperature increased AER and Tr but slightly decreased P(G) and g(S). &apos;Kasalath&apos; (low GS activity) showed higher AER than &apos;Akenohoshi&apos; (high GS activity) at high light intensity, leaf temperature and [O(2)].
Conclusions Our results demonstrate that photorespiration is strongly involved in NH(3) emission by rice leaves and suggest that differences in AER between cultivars result from their different GS activities, which would result in different capacities for reassimilation of photorespiratory NH(3). The results also suggest that NH(3) emission in rice leaves is not directly controlled by transpiration and stomatal conductance.

DOI： 10.1093/aob/mcr245

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CROP SCIENCE SOC JAPAN  

NH(3) emission from leaves of three rice (Oryza sativa L.) cultivars, Akenohoshi, Shirobeniya and Kasalath, was examined using a simple open chamber system. In the three cultivars, NH(3) emission rate (AER) and NH(4)(+) content of leaves decreased with decreasing NH(4)(+) concentration in the root medium, but these values differed significantly with the cultivar. In the daytime, AER, NH(4)(+) content and glutamine synthetase (GS) activity in leaves changed similarly with maximum values around midday. Akenohoshi showed significantly lower AER and NH(4)(+) content but higher GS activity than Kasalath. The difference in AER among the rice cultivars may be related to the activity of GS involved in photorespiratory NH(3) recycling. Akenohoshi can be a breeding material useful for improving N recycling.

DOI： 10.1626/pps.14.249

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：INT SOC HORTICULTURAL SCIENCE  

Freshwater is an essential resource which should be wisely used and shared between the different sectors especially in rapidly developing countries such as Vietnam. In Vietnam, agricultural production and farming systems have been intensified and diversified to follow the growing economy and food demands. However, intensification of agriculture resulted in environmental damage such as eutrophication of surface and ground water, and soil degradation. Sustainable management of soil and water is thus needed to share limited resources between farming systems such as rice, vegetables and animal husbandry. However, the diversified structure of the farming systems makes it difficult to evaluate the impacts from the integrated farming systems. To cope with the diversity and complexity, a mathematical model-based approach would be useful in describing these complex processes and their inter-actions. The present study aims to develop a mathematical model to simulate the dissolved nitrogen dynamics in a paddy field in the Red River Delta, Vietnam. A series of field experiments under different fertilization conditions was carried out in an experimental paddy field of Hanoi University of Agriculture, Vietnam. Ammonium and nitrate nitrogen were monitored in the paddy field water and adjacent canal water, based on which a mathematical model was developed to estimate the concentration of dissolved nitrogen in surface water of the paddy field. As a result, the present model could represent the dynamics of the dissolved nitrogen in relation to farming practices such as fertilizer application. Despite the applicability, further improvement of the model considering nitrogen budget on the soil-water interface would be necessary in order to better represent the nitrogen dynamics and optimize fertilizer applications in both timing and amount.

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The hydraulic characteristics of plant organs and the absorption functions of roots of corn and tomato plants were analyzed by using a specialized high-pressure flowmeter (HPFM), which was equipped with a root chamber as well as a coupling to connect to the plant organs. The HPFM can detect changes in the hydraulic properties of the respective parts of the plant body. The hydraulic resistances of the leaf and root decreased with an increase in the water flow rate
this dependence was remarkable at low water flow rates. On the other hand, the hydraulic resistance of the stem was only slightly affected by the water flow. However, a positive linear relationship between hydraulic conductance (reciprocal of resistance) and water flow rate was found for the shoot, stem, and root, respectively. Further, the rate of nutrient (NO3 -1) absorption by the root was evaluated from the water flow (root water absorption) and NO3- concentration in the xylem sap exuded from the root stump. The high-pressure flowmeter with the root chamber can be used for studying water and nutrient transport in plants and their responses to environmental elements.

DOI： 10.2525/ecb.49.99

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Language：English   Publishing type：Research paper (scientific journal)  

In order to analyze the growth of corn plants and the level of salinization in and around an irrigated field in the Yellow River basin, surveys of plant growth, soil and water quality were conducted in August and September 2007. Plant growth parameters such as height, leaf nitrogen content and maximum quantum yield of photosystem I (Fv/Fm), and chemical characteristics of the Yellow River water, irrigation canal water, ground water, drainage canal water, saline seep water and field soils were measured. There was a significant difference in corn growth in the irrigated field, that is, plant height, leaf nitrogen content and Fv/Fm decreased as the drainage canal for removing the saline seep water was approached. The electrical conductivity (EC) and various dissolved ion concentrations of the ground water in the field exhibited remarkable high values compared to those of the Yellow River water and the irrigation canal water. When a comparion between three survey points in the field (the nearest, middle and the farthest to the drainage canal) was made, it became clear that there existed clear gradients of those concentrations, that is, they showed the highest values at the nearest point and caused the poorest growth of corn plant at the point. The EC and ion concentrations of the saline seep at the foot of the river terrace made of loess showed extremely high values. The drainage canal for removing the seep water, which separated the survey field and the terrace, was not lined and hence the salty water in this canal seemed to seep into the surounding fields. These results obtained from his study suggest that the cultivation system such as irrigation techniques and drainage facilities should be improved for sustaining productive irirrigated agriculture in this area.

DOI： 10.2525/ecb.49.127

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Language：English   Publisher：The Society of Eco-Engineering  

A system of large soil columns was used to examine water and ion transport dynamics and salt accumulation in the soil profile, with special reference to the effects of the root absorptive functions of crops. The soil column system was equipped with on-line systems for measuring the upward flux of water (i.e. the evapotranspiration rate) and the soil water content. The distribution and accumulation of ions in the soil profile and the crop xylem sap were analyzed using ion chromatography. Comparing water loss between a corn cropped column with the uncovered soil surface and a corn cropped column with the soil surface covered to inhibit soil surface evaporation indicated that root water absorption (i.e. transpiration) accounted for about 75% of the evapotranspiration. This suggests that root water absorption is the most significant driving force for transporting water and ions from groundwater to the root zone. The major essential ions for crop growth were actively absorbed by roots and were largely absent from the root zone. In contrast, soluble salts such as NaCl were scarcely absorbed and largely remained in the root zone. Furthermore, soil surface evaporation drove the upward movement of water and salt from the root zone to the soil surface, which increased salt accumulation at the soil surface. Thus, salt accumulation is caused mainly by active water uptake and selective ion absorption by crop roots, and these effects can be enhanced by the salinity of groundwater and the higher evaporative demand found in arid and semi-arid regions.

DOI： 10.11450/seitaikogaku.22.93

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Language：English   Publishing type：Research paper (scientific journal)  

The energy partitioning in photosystem II (PSII) and the susceptibility to photoinhibition in PSII were investigated in flag leaves of two rice cultivars, Shirobeniya (a traditional japonica) and Akenohoshi (an improved japonica-indica intermediate) grown under standard-nitrogen (N) (SN) and low-N (LN) conditions. N-deficiency resulted in significant decreases in total dry weight, net photosynthetic rate (PN), the energy flux via carboxylation (Jc), and content of ribulose-1,5- bisphosphate carboxylase/oxygenase (Rubisco) in flag leaves in the two cultivars, and these parameters of Shirobeniya were lower than those in Akenohoshi under the LN condition. In the two cultivars, the energy flux via alternative electron flow was significantly increased by N-deficiency, which was accompanied by enhanced activity of superoxide dismutase (SOD). Although under the LN condition no cultivar differences were found in Ja and SOD, ascorbate peroxidase activity in Shirobeniya was lower than that in Akenohoshi. N-deficiency resulted in more significant increases in the susceptibility to photoinhibition (the degree of decrease in maximum quantum yield of PSII), hydrogen peroxide (H2O2) content and malondialdehyde content after exposure to high irradiance in Shirobeniya than those in Akenohoshi. These results indicated that the increased susceptibility to photoinhibition in the LN plants of Shirobeniya was mainly due to oxidative damages to chloroplasts, resulting from lower carboxylation and H2O2-scavenging capacities. Therefore, both carboxylation and H2O2-scavenging capacities could be important factors in determining the cultivar difference in the productivity of rice under LN conditions.

DOI： 10.1626/pps.13.11

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Language：Japanese   Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.228.0.96.0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CROP SCIENCE SOC JAPAN  

Effects of nitrogen (N) deficiency oil photosynthetic gas exchange and photosystem II (PSII) photochemistry of flag leaves during grain-filling stage Were investigated in six rice cultivars, Kasalath (a conventional indica), IR36 (an improved indica), Shirobeniya (a conventional japonica), Nipponbare (an improved japonica), Akenoltoshi (an improved japonica-indica intermediate type) and BS1429 (an improved tropical japonica, a new plant type line) grown hydroponically in N-sufficient (NS) and N-deficient (ND) solution. From 3 to 24 days after heading (DAH), net photosynthetic rate (P-N), maximum quantum yield of photosysteln II (PSII) (F-v/F-m), quantum yield of PSII electron transport (Phi(PSII)), and contents of chlorophyll (Chl) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rebisco) in the flag leaves decreased, particularly under the ND condition in all six cultivars. A substantial difference was observed among the ND plants for the sustainability index (SI, the ratio of the value at 24 DAH to that at 3 DAH) of P-N, F-v/F-m, Phi(PSII), Chl content and Rubisco content; SIs of those parameters of Akenohoshi, BSI429, Nipponbare and Shirobeniya were higher than those of IR36 and Klsalath. The SI of P-N showed significant: positive correlations with those of F-v/F-m, Phi(PSII), and the contents of Chl and Rubisco under the ND condition. It was concluded that the sustainability of photosynthesis in the flag leaves was mainly clue to those of PSII photochemistry and electron transport, Which was associated with the maintenance of Chl and Rubisco under the ND condition.

DOI： 10.1626/pps.12.285

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Effects of nitrogen (N)-deficiency on midday photoinhibition in flag leaves were compared between two contrastive Japanese rice cultivars, a traditional japonica cultivar with low yield, cv. Shirobeniya (SRB), and a japonica-indica intermediate type with high yield, cv. Akenohoshi (AKN). Both cultivars were grown under high-N and low-N conditions. At midday, low-N supply resulted in more intensive reductions in net photosynthetic rate, stomatal conductance, maximal quantum yield of photosystem II (PSII) and quantum yield of PSII electron transport in SRB than in AKN, indicating that SRB was more strongly photoinhibited than AKN under low-N condition. At midday, the low-N plants of two cultivars showed higher superoxide dismutase (SOD) activities than the high-N plants. However, ascorbate peroxidase (APX) activity was maintained in AKN but significantly decreased in SRB under low-N condition (N-deficiency). In contrast, hydrogen peroxide (H(2)O(2)) content in SRB significantly increased under low-N condition, indicating that the susceptibility to midday photoinhibition in the low-N plants of SRB is related to the increased H(2)O(2) accumulation. It is suggested that the midday depression in photosynthesis may be a result of oxidative stress occurring in the low-N plants in which antioxidant capacity is not enough to cope with the generation of H(2)O(2). Therefore, H(2)O(2)-scavenging capacity could be an important factor in determining the cultivar difference of midday photoinhibition in flag leaves of rice under low-N condition.

DOI： 10.1007/s11099-009-0038-z

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：VERSITA  

Water deficit and salt accumulation in soil presents serious problems to crop production in semi-arid regions. These problems depend on the active transpiration stream and the selective absorption of ions by crop roots. In this study, a large sized soil column system was used to examine the dynamics of water and ion transport and salt accumulation in soil layers. Special reference was placed on the effects of the active and selective absorption by roots of different crops (i.e., corn plants, sunflower plants and no plants). The column system was equipped with on-line systems for the control of groundwater level. Soil water content sensors enabled time-course evaluations of the volumetric water content and hence upward flux of the groundwater in the soils at different depths. Furthermore, the distribution and accumulation of ions in soil layers, plant organs and xylem sap were analyzed using ion chromatography. In this column experiment, diurnal and longer term changes in water movement and ion accumulation in soil, affected by root absorption characteristics of plants, were evaluated quantitatively. The results demonstrated that the column system was applicable for the quantitative analysis of the effects of root absorption by different crops on water deficit and salinization in soils.

DOI： 10.2478/s11756-009-0082-y

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：VERSITA  

In order to analyze the salt transport affected by roots and its effects on soil salinity in an experimental irrigated field newly established in an alluvial valley of the Yellow River in China, spatial distribution of ions contained in waters, soils and crops relevant to these phenomena were evaluated there. During the intensive surveys conducted in year 2007-2008, the Yellow River water, irrigation canal water, groundwater, field soils and crops, etc. were sampled and their chemical characteristics such as electrical conductivity, concentrations of ions Na(+), Ca(2+), Mg(2+), K(+), Cl(-), SO(4)(2-) and NO(3)(-) were measured. Irrigation seemed to cause increases in the concentrations of ions Na(+), Cl(-) and SO(4)(2-) in the groundwater. Although those were also major ions contained in the field soil, the soil was classed as saline but not sodic according to the standard classification. On the other hand, K(+), which is one of the major essential nutrients for plant growth, was highly concentrated in the crops, while Na(+) was not concentrated because of crop&apos;s poor ability to absorb it. The ion concentration within the plant body seemed to be reflected by the active and selective ion uptake by roots and the transpiration stream. Furthermore, salt accumulation in the surface-irrigated field largely depended on the upward transport of water and ions in the soil pro. le affected by root absorption capacity. The information obtained in this study will contribute to the development of scientific methods for sustainable and effective plant production in irrigated fields.

DOI： 10.2478/s11756-009-0090-y

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In order to analyze absorption and transport of water and ions in plants affecting the salinization in the root zone through physical and physiological processes, we measured water and ion uptake by roots, transpiration rate, leaf conductance, and ion concentrations in root xylem sap and other plant tissues of corn and sunflower grown under saline conditions using a nutrient film technique system. The rate of root water uptake was lower in corn than in sunflower, where the daytime stomatal closure in response to the excessive water stress induced by the saline solution was occurred in corn but not in sunflower. NO 3 - , PO 4 3- and K + were highly concentrated in the xylem sap as a result of the active and selective uptake of nutrients by roots of both corn and sunflower. Na + , which is not an essential element for plant growth, was not highly concentrated in the xylem sap or plant tissues of corn because corn exhibited a poor Na + absorption and transportation ability. On the other hand, sunflower had a greater ability to absorb water, Na + , Mg 2+ , Ca 2+ , Cl - , and SO 4 2- , and to transport these ions from the roots to the shoot. These differences in absorption and transport of water and ions indicate that sunflower is more salt tolerant than corn. The effects of these absorption and transport characteristics on plant growth and soil salinity should be taken into account for sustainable and effective plant production in salinized crop fields. © 2009, The Society of Agricultural Meteorology of Japan. All rights reserved.

DOI： 10.2480/agrmet.65.1.7

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The objective of this study was to establish the correlation of the chlorophyll meter (SPAD) readings with the contents of chlorophyll (Chl) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), the gross photosynthetic rate (PG), and the maximum quantum yield of photosystem II (PSII) (Fv/Fm) in flag leaves of rice (Oryza sativa L.) in ripening stage. The SPAD readings significantly correlated with the Chl content, the Rubisco content, PG and Fv/Fm (R2=0.848, 0.648, 0.671 and 0.712, respectively), which suggests that the SPAD meter has the potential to estimate the photosynthetic capacity of the flag leaves. However, both PG and Fv/Fm had a stronger relationship with the Rubisco content than the SPAD readings, indicating that the PSII photochemical and CO2 assimilation capacities are strongly influenced by the Rubisco content. Therefore, accurate calibration would be indispensable to obtain the physiological information from the SPAD readings of flag leaves.

DOI： 10.1626/pps.12.50

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Biotron Institute  

Single-truss and high density cultivation of tomato plants (Lycopersicon escultcntum Mill.) has great advantages in controlling the plants and stable production. In this cultivation, an effective application of short-term salt stress for high quality tomatoes was examined by analyzing mass transport to fruits via phloem. Tomato plant were grown by soil-less culture with nonwoven fabric system for single-truss and high density cultivation, where short-term salt stress was induced for just 2 weeks at the stage of rapid fruit growth by adding the concentrated deep seawater to the standard nutrient solution (electric conductivity (EC), 1.2 dS m-1) to increase EC by 13.5 dS m-1 Although fresh weight of the fruits was restricted by salt stress, dry matter ratio of the fruits was increased, Soluble solid concentration and flux in the phloem sap was accelerated not only during the short-term, salt stress but also after the removal. Concentrations of Na +, K+, and Mg+ in the phloem, sap were also enhanced by the concentrated deep seawater. Consequently, sugar concentration of the fruits was significantly increased by short-term salt stress. These results may contribute to stable and high production of high quality tomatoes in single-truss and high density cultivation.

DOI： 10.2525/ecb.47.37

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Language：Japanese   Publisher：The Society of Eco-Engineering  

The concentrated deep seawater, which is highly enriched in not only Na but useful minerals such as Mg, K and Ca is expected to be applicable to the production of high quality tomatoes. In the previous study, we reported that the short term salt stress treatment with the concentrated deep seawater can produce the high sugar tomatoes through osmoregulation in the phloem transport to fruits. In this study, the specificity of fruit quality of tomato grown with the concentrated deep seawater was examined with special reference to antioxidation, amino acid metabolism and sensory properties of fruits under the three different salt stress treatments. Tomato plants (<I>Lycopersicon esculentum</I> Mill.) were grown in hydroponic pots. In each of salt stress treatments, the concentrated deep seawater (DSW) or the surface seawater (SSW) or pure NaCl (NaCl) was applied to the nutrient solution for only two weeks at the stage of rapid fruit growth, where an electric conductivity of the nutrient solution was raised from 1.0 dSm<SUP>-1</SUP> to 15 dSm<SUP>-1</SUP>. The two weeks salt stress treatment with the concentrated deep seawater brought high quality tomatoes with higher accumulations of sugar, acids, minerals of Mg and K, functional amino acids of &gamma;-aminobutyric acid and proline and with good flavor. Furthermore, the activity of superoxide dismutase in DSW treatment was low as compared with that in SSW treatment and NaCl treatment. However, in this experiment, the significant differences in fruit quality (i.e. growth, contents of sugar, acid and functional amino acids) were not found among the three different salt stress treatments.

DOI： 10.11450/seitaikogaku.21.59

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Language：Japanese   Publisher：Japanese Society of Agricultural, Biological and Environmental Engineers and Scientists  

In the root zone of the soil-less culture, stress conditions such as low temperature, drought and high salinity can be easily introduced and controlled by applying physical and chemical characteristics of water. These stress conditions in the root zone cause depres-sions in root absorption and leaf photosynthesis and resultantly bring osmotic stress and oxidative stress in the plant body. The osmotic stress and the oxidative stress can induce the respective plant adaptive functions of osmotic adjustment and antioxidation. These plant functions can be expected to bring high quality and value-added vegetables enriched with sugars, functional amino acids, antioxidants <I>etc</I>., if the induced stresses are not so serious that the stress damages are not fatal without the extreme depression in growth. In this paper, two examples of the short term stress application only to roots for production of value-added vegetables are demonstrated. By the one week application of low temperature (5°C) stress only to roots of spinach plants (<I>Spinacia oleracea</I> L.), sugars, ascorbic acid and Fe²⁺ were significantly enriched in leaves. Furthermore, concentrations of harmful substances of NO₃^- and oxalic acid were extremely decreased. The two weeks salt stress treatment to roots of tomato plants (<I>Lycopersicon esculentum</I> Mill.) by applying the Muroto deep seawater at the stage of rapid fruit growth induced the osmotic adjustment and the antioxidation, which brought high quality tomatoes enriched with sugar, minerals, functional amino acids and good flavour without occurrence of extremely small-sized fruits and blossom-end rot. These verify that the short term stress application only to roots in the soil-less culture is reliable for production of high quality and value-added vegetables.

DOI： 10.2525/shita.20.210

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

Water deficit and salt, accumulation in soil are serious problems in crop fields in semi-arid regions, and these problems are likely to depend oil active transpiration and selective ion absorption by crop roots. In this study, a large sized soil column system was newly developed, and a preliminary experiment with the system was conducted to examine the system performance for analyses of dynamics of water and ion transport. and salt accumulation in soil with special reference to effects of the active and selective absorption of roots of different crops (i.e., corn plants, sunflower plants and no plants). The column system was equipped with on-line systems for the control of groundwater level and the TDR Measurement, which enabled time course evaluations of upward flux of the groundwater, volumetric water content of soils at, the different depths and electrical conductivity of the extract from the saturated soil. Furthermore, distribution and accumulation of ions in soil layers, plant organs and xylem sap were analyzed using an ion chromatograph. In this column experiment, diurnal and long Cerin daily changes in water movement and ions accumulation in soil affected by characteristics of root absorption were evaluated. This call Suggest that, this column system is applicable for quantitative analyses of effects of root absorption of different, crops on water deficit and salinization in soils, aiming at proposing a scientific method of the crop rotation for the environmentally conscious agriculture in semi-arid regions.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

Drought resistance and recovery of greengram (Vigna radiata L. Wilczek) varieties (vars.), Kanti, Yezin-4, VC1973A and V3726, improved varieties in Myanmar, were compared in pot experiments based on the parameters related to growth and photosynthesis. At the vegetative stage (30th day after planting), the plants were subjected to four-day drought treatment during which the water supply was reduced to 20% of the control. At the end of the drought treatment, the plants were re-watered for three days as a recovery treatment. A significant varietal difference was observed in growth parameters, CO exchange rate (CER), stomatal conductance (G,), PSII electron transport (ETR) and non-photochemical quenching (NPQ) at the end of drought and re-watering treatments. Of the four varieties, vars. Kanti and Yezin-4 sustained a comparatively large value of G, because of their relatively higher sustainability of CER and ETR and having lesser NPQ under drought condition. This result suggests that the CO2 assimilation and PS function in both varieties were less affected by drought, and could continue photosynthetic energy flow. Moreover, both vars. Kanti and Yezin-4 showed a better recovery in growth, gas exchange and PSII function at the rewatering treatment. There was the evidence that greengram (var. Kanti) had a high drought-resistance and quick recovery, compared with blackgram (Vigna mungo L. Hepper, var. P-11-30) and soybean (Glycline max L., var. Asoaogari).

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

Salinity is an ever-present hazard in irrigation agriculture. In order to conduct experiments on the control of salinity and sodicity in surface-irrigated fields, an experimental field was established at Pirigbu village (Baiyin, Gansu, China) located in an alluvial valley of the Yellow River in September 2007. The background to and the objectives and methodology of the experiments are described, and the natural condition of the study area and the fundamental knowledge and information on this subject are summarized.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

In order to analyze the state of salinization and alkalization in and around an experimental irrigated field newly established in an alluvial valley of the Yellow Ricer, concentrations of ions contained in waters, soils and crops relevant to these phenomena were measured there. During the intensive surveys conducted in June, August and September 2007, the Yellow River water, irrigation canal water, groundwater, field soils and crops, etc. were sampled and their chemical characteristics such as electrical conductivity, pH, concentrations of ions Na+, Ca2+, Mg2+, K+, Cl-, SO42- and NO3- were measured. The results obtained are summarized as follows:
Irrigation seems to cause increases in the concentrations of ions Na+, Cl- and SO42- in the groundwater. Although those are also major ions contained in the field soil, the soil is classed as saline but not sodic according to the standard classification. On the other hand, Na+ is not concentrated in the crops because of their poor ability to absorb it. This seems to be one of the factors that cause salinization and alkalization of soil and water in irrigated fields. Therefore, cultivation techniques that use the ability of specific crops to absorb much Na+ and store it in shoots should be developed for effective and sustainable use of the irrigated field.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

An experimental field was established in Pingbu village extending along the Yellow River (Baiyin, Gansu, China) to conduct experiments on the control of salinity and sodicity in surface-irrigated fields, and an observation system for measuring meteorological and hydrological elements relevant to soil salinization and alkalization was installed in it. The outline of the observation system is shown; principles of measuring such elements are examined and their limitations are pointed out in case of necessity. Furthermore, careful considerations are given to the system so that the system could measure such elements as accurately as possible.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：INT SOC HORTICULTURAL SCIENCE  

The concentrated deep seawater has been discharged abundantly in the processes manufacturing many kinds of goods from the deep seawater. In this study, a suitable application of the concentrated deep seawater for the high quality tomato production was examined. Tomato plants (Lycopersicon esculentum Mill.) were grown in the NFT system and the hydroponic pots, where the concentrated deep seawater was applied for the short-term salt stress treatment for only two weeks at the stage of rapid fruit growth. Physiological effects of the application of the concentrated deep seawater were analyzed with special reference to osmoregulation in the phloem transport, antioxidant system, amino acid metabolism and fruit quality. From these physiological analyses, it was verified that the short-term application of the concentrated deep seawater at the stage of rapid fruit growth can induce the osmoregulation in the phloem transport and the antioxidant system, which can produce high quality tomatoes enriched in sugar, minerals, functional amino acids and good flavour without occurrence of extremely small-sized fruits and blossom-end rot.

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Language：English   Publisher：Biotron Institute  

Continuous measurement of the growth of a storage organ is often required, for analyzing environmental effects on crop production. Various techniques have been used for measuring storage organ growth. Non-contact methods are desirable for the growth analysis of an intact storage organ. Recently, laser beam-based measuring devices have been widely utilized in the industry for non-contact measurements of the width, length, or thickness of an object. These devices can also be effective tools for evaluating storage organ growth in plants. This article presents successful examples of the use of laser beam-based devices for non-contact growth measurements of two different types of storage organs, i.e., a tomato fruit and a sweetpotato tuberous root.

DOI： 10.2525/ecb.45.251

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

The effects of nitrogen (N) supply restriction on the CO2 assimilation and photosystem 2 (PS2) function of flag leaves were compared between two contrastive Japanese rice cultivars, a low-yield cultivar released one century ago, cv. Shirobeniya (SRB), and a recently improved high-yield cultivar, cv. Akenohoshi (AKN). Both cultivars were solution-cultured at four N supply levels from N4 (control) to N1 (the lowest). With a reduction in N-supply, contents of N (LNC), ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO), and chlorophyll (Chl) in flag leaves decreased in both cultivars. In parallel with this, the net photosynthetic rate (P-N), mesophyll conductance (g(s)), and stomatal conductance (g(s)) decreased. PN was more dominantly restricted by g(m) than g(s). The values of P-N, g(m), and RuBPCO content were larger in AKN than SRB at the four N supply levels. The content of Chl greatly decreased with N deficiency, but the reduction in the maximum quantum yield of PS2 was relatively small. Quantum yield of PS2 ((Phi(PS2)) decreased with N deficiency, and its significant cultivar difference was observed between the two cultivars at N I: a high value was found in AKN. The content ratio of Chl/RuBPCO was also significantly low in AKN. The low Chl/RuBPCO is one of the reasons why AKN maintained a comparatively high PN and (Phi(PS2) at N deficiency. The adequate ratio of N distribution between Chl and RuBPCO is the important prerequisite for the efficient and sustainable photosynthesis in a flag leaf of rice plant under low N-input.

DOI： 10.1007/s11099-007-0084-3

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Language：English   Publisher：Biotron Institute  

Transpiration streams are induced by evaporative demand from the environment and distribute water solution from roots to tissues and cells in the respective organs through the complicated pathways. In these processes, physiological functions of plants such as stomatal movement, photosynthesis, phloem and xylem transport, nutrient uptake and expansive growth are affected by transpiration streams. Therefore, many kinds of techniques for measuring evaporative demand and transpiration streams in leaf boundary layer, leaves, fruits, stem, roots and plant canopy have been developed. The information about transpiration streams provided by the developed techniques must be more informative with cooperative measurements of plant physiological functions and must be more effective for the speaking plant approach to the environment control.

DOI： 10.2525/ecb.45.223

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Language：Japanese   Publisher：The Society of Eco-Engineering  

A suitable application of the concentrated deep seawater for the high quality tomato production was examined by analyzing phloem transport to fruits. Tomato plants (<I>Lycopersicon esculentum Mill.</I>) were grown in the NFT system, where the concentrated deep seawater was applied to the nutrient solution at the stage of rapid fruit growth for the short-term (only two weeks) salt stress treatment. A heat-ring method was newly applied to the tomato pedicel to evaluate phloem fluxes of sap and soluble solids and concentrations of soluble solids in the phloem sap, and effect of the short-term application of the concentrated deep seawater was analyzed with special reference to osmoregulation in the phloem transport to tomato fruits. The phloem sap flux into the fruit was decreased by the short-term salt stress, but the soluble solids flux through phloem was significantly enhanced. The concentration of soluble solids in the phloem sap was remarkably raised from the start of the salt stress treatment, which was kept at the higher levels even after the removal of the salt stress. Concentrations of K<SUP>+</SUP>, Na<SUP>+</SUP> and Mg<SUP>2+</SUP> in the phloem sap were also raised by the application of the concentrated deep seawater. From these quantitative analyses of the phloem transport to tomato fruits, it was verified that the short-term application of the concentrated deep seawater at the stage of rapid fruit growth can induce the osmoregulation in the phloem transport to fruits and produce the high quality tomatoes enriched with sugar and minerals.

DOI： 10.11450/seitaikogaku.18.181

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Language：Japanese   Publisher：The Society of Eco-Engineering  

The deep seawater is a profitable natural resource with the stable advantages of low temperature, nutrient-rich and purity and has been applied to many kinds of industry and product. In the processes producing the mineral-enriched table salt and drinking water from the deep seawater, the concentrated deep seawater is abundantly discharged, which is highly enriched in not only Na⁺ but useful minerals such as Mg²⁺, K⁺ and Ca²⁺, <I>etc.</I> Therefore, effective application of the concentrated deep seawater has been required, and in this study, a suitable application of the concentrated deep seawater to the production of high quality tomato was examined. Tomato plants (<I>Lycopersicon esculentum</I> Mill.) were grown by soil-less culture with the nutrient film technique (NFT), where the short-term salt stress was induced by applying the concentrated deep seawater. For only two weeks at the stage of rapid fruit growth, the concentrated deep seawater was added to the standard nutrient solution to increase the electric conductivity of the nutrient solution from 1.2 to 13.5 dS m<SUP>-1</SUP>. From physiological analyses of the fruit quality, it was suggested that the short-term salt stress treatment with the concentrated deep seawater at the stage of rapid fruit growth can bring high quality fruits enriched in sugar, minerals and good flavor without occurrence of extremely small-sized fruits and blossom-end rot.

DOI： 10.11450/seitaikogaku.18.119

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Language：Japanese  

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Publisher：CROP SCIENCE SOCIETY OF JAPAN  

DOI： 10.14829/jcsproc.222.0.180.0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

The experimental materials used here were 12 rice cultivars released and grown in the past one century in the southern area of Japan and two African cultivars. With plants water-cultured under standard and low nitrogen applications, their dry matter weight, leaf area and net assimilation rate (NAR), rubisco content and chlorophyll content in leaves were investigated. Results obtained were as follows: By reducing the nitrogen concentration of culture-solution to 10% of the standard, the average plant dry matter weight and leaf area of the 14 cultivars were decreased to 25% and 20%, respectively. To evaluate the growth sustainability of cultivars grown under the low nitrogen application, the sustainability index (SIL) was used here. SIL of dry matter weight (SIL-DM), leaf area (SIL-LA) and NAR (SIL-NAR) were significantly different among cultivars. For these three parameters, large values were found in Koshilukari, one of the high quality cultivars widely grown in Japan today, and the small,ones,were observed in old, traditional cultivars, such as Asahi and Shinriki, and in G174 (O. glaberrima). A significant cultivaral difference in response to nitrogen application was also found in the rubisco and chlorophyll contents and their SILs.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

The responses to drought and flooding stresses and the recovery from stress-induced damages were compared between three mungbean cultivars, Chinese (CN), and newly released cultivars in Myanmar, VC2991-112B-1B (VC) and KPS2 (KP). Growth, gas exchange rate and chlorophyll fluorescence quenching of these cultivars were investigated. The results were as follows: (1) CN was sensitive to both drought and flooding treatments compared to the other cultivars. VC and KP were less sensitive to drought and flooding, respectively. (2) The photosynthetic rate (P(N)) and stomatal conductance (G(s)) in VC were less affected by drought, with a quick recovery by re-watering. On the other hand, both parameters in KP were strongly depressed by drought, but less by flooding. (3) VC showed a higher value for the quantum yield of photosystem II (Phi(e)) and a lower value for the photorespiration ratio (P(R)/T(C)) than the other cultivars in the drought treatment. KP had a higher Phi(e) and lower P(R)/T(C) in the flooding treatment. (4) The stomatal behavior was closely related to the stress-tolerance of mungbean cultivars. A partial retainment of gas exchange under the stress conditions was essential to sustain electron transport in the photosystems and prevent functional damages caused by excessive accumulation of energy in leaves.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

Kenaf (Hibicus Cannabinus) and napiergrass (Pennisetum purpureum) are known as C3- and C4-plant species with a high biomass productivity and drought tolerance, respectively. Their growth features and photosynthetic responses to mild and severe drought treatments were investigated in pot cultivations. The results obtained were as follows: 1) The biomass production of kenaf was large, almost similar to that of napiergrass. The CO2 exchange rate (CER) and stomatal conductance (Gs) of kenaf were high and stable during the sunshine time, while those parameters of napiergrass had a decreasing tendency toward the afternoon. 2) CER, Gs and mesophyll conductance (Gm) in both species were depressed in the drought treatments. C4-plants are known to have a high tolerance to droughts, but here in kenaf, CER showed a less depression compared to that of napiergrass in the drought treatments, and by re-watering CER of kenaf was quickly recovered. On the other hand, Gm in napiergrass was more sensitive to the drought treatments and its recovery was incomplete. 3) The drought treatments did not strongly affected the maximum quantum yields in photosystem H (Fv/Fm) in both species, but had a significant effect on the quantum yield (Phi e) in the stable photosynthetic condition. The depression of Phi e was significantly larger in napiergrass, and its recovery by re-watering was poor. The high tolerability and quick recovery in kenaf is presumed to depend on photorespiration, by which the excessive energy in leaves was effectively dissipated to protect the photosynthetic apparatus.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Biotron Institute  

DOI： 10.2525/ecb.43.305

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：KYUSHU UNIV, FACULTY AGRICULTURAL PUBLICATIONS  

The electric conductivity of a leaf (LEG) was determined with an insulation resistance tester, and discussed its relationship with Na+ content in a leaf (LNC) and the photosynthetic activity in salt-stressed rice cultivars. The measurements were carried out using three cultivars of O. sativa and O. glaberrima grown at the middle vegetative growth stage. The plants showed a clear response to the salt treatment within 24 hours after its application. Both LEG and LNG in these cultivars increased with an increase in NaCl concentration in culture solution from 0 to 0.1 mumol L-1. LEC had a close linear relationship with LNG in each cultivar. A negative relationship was found between LEG and gross photosynthetic rate (P-g). The stomatal conductance (G(s)) and mesophyll conductance (G(m)) decreased with an increase in LNC. A clear cultivaral difference was recognized in responses to salt treatments. LEG was regarded as a useful indicator for the estimation or diagnosis of LNG and photosynthetic activity in salt-stressed rice cultivars.

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Language：English   Publisher：Japanese Society of Agricultural, Biological and Environmental Engineers and Scientists  

In order to examine the short-term response of tomato (<I>Lycopersicon esculentum</I> Mill.) plants to water stress, we investigated the dynamics of fruit growth and water balance in growing fruits under the well-watered and the water deficit conditions. Under the well-watered condition, most (84%) of pedicel sap flux toward the fruit contributed to fruit expansion, and the residual (i.e. only 16%) was lost by transpiration from the fruit and its calyx. The most dominant component of the fruit water balance was the phloem sap flux, since a major part (i.e. 70%) of the sap delivered into the fruit was brought by phloem transport. On the other hand, xylem transport made a lesser contribution to the fruit expansion and exhibited larger susceptibleness to water stress. Under the water deficit condition, the fruit growth rate was depressed to 36% of well-watered plants, while phloem sap influx to the fruit was less affected. Xylem sap backflow occurred frequently under the water deficit condition, and the net influx of xylem sap during the whole day was nearly zero. The phloem transport solely sustained the fruit growth under water stress. This study quantitatively demonstrated that water deficit results in smaller fruits with higher sugar concentrations through different responses of phloem and xylem transport to water stress.

DOI： 10.2525/ecb1963.42.225

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：INTERNATIONAL SOCIETY HORTICULTURAL SCIENCE  

The occurrence of xylem sap backflow from fruit is known in several woody crops. In tomatoes (Lycopersicon esculentum Mill.), it is not generally accepted that the xylem backflow occurs in the plant, although our preliminary experiments revealed that the expanding fruit under water deficit condition loses slight water through xylem backflow. In this investigation we confirmed the occurrence of xylem backflow from the fruit using the fluorescent dye, Lucifer Yellow CH (LYCH), which is unable to cross the plasmalemma, as a tracer for apoplastic movement of water. For introduction of LYCH into the fruit, a small hole was made in the side of the fruit, which reached to the center of the fruit. About 0.1 ml of 1 % LYCH solution was poured into the hole in the dark period. The plant was exposed to the light (PPFD, 250 mu mol m(-2) s(-1)) for 6 hours, and then transections of the pedicel, the peduncle and the stem were soon observed with fluorescent microscopy. The intense fluorescence of LYCH was observed in the xylem region only. In well-watered plants, the LYCH flowed out about 30 mm distance from the fruit. In water deficit plants, the LYCH centripetally moved more than 100 mm, and it consequently reached to the stem. Results indicate xylem sap flows back from the fruit during the light period under the water deficit condition. The finding involves a complicated process of sugar and calcium accumulation in the developing tomato fruit.

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Language：Japanese   Publisher：The Japanese Society of Agricultural Machinery and Food Engineers  

DOI： 10.11357/jsam1937.64.Supplement_77

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In order to elucidate stomatal response to wind, leaf gas exchange and stomatal conductance in an intact leaf of cucumber plants (Cucumis sativus L.) were measured under different conditions of air current and humidity. A leaf gas exchange cuvette was improved for individual measurements on the abaxial and adaxial leaf surfaces and for adjustment of the leaf boundary air current, where leaf boundary layer conductance can be adjusted at a desired value within a range from 0.3 mol m-2s-1 to 1.0 mol m-2s-1. Rates of leaf gas exchange and stomatal conductance were higher on the abaxial surface than on the adaxial surface. Stomatal response to wind was appeared more sensitive on the abaxial surface, while leaf gas exchange and stomatal conductance on the adaxial surface was scarcely affected by wind. Under the humid air condition, increase in leaf boundary layer conductance significantly enhanced stomatal conductance as well as rates of transpiration and photosynthesis on the abaxial surface. On the other hand, under the dry air condition, stomatal conductance was depressed by increase in leaf boundary layer conductance with little effect on transpiration and photosynthesis. These opposite changes in stomatal conductance found under the humid and dry air conditions were proved visually as change in stomatal aperture by the microscopic observation of the abaxial leaf surface. This stomatal response to wind found on the abaxial surface was not related to feedback stomatal response to transpirational water loss and intercellular CO2 concentration in the leaf. The mechanism of stomatal response to wind was explained on the basis of water balance within the stomatal complex and on the antagonism relationship between turgors in guard and epidermal cells.

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DOI： 10.3117/rootres.10.19

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DOI： 10.2525/ecb1963.39.53

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DOI： 10.2525/ecb1963.39.43

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Publishing type：Research paper (scientific journal)  

A pressure flow meter system was newly developed for measuring hydraulic characteristics of plant organs. In the system, the pressurized water flow through plant organs was given at a desired rate by regulating the applied pressure, and hydraulic resistance or conductance of plant organs was determined from the flow rate and the applied pressure at intervals of about 5 minutes. By applying the system, individual evaluations of hydraulic characteristics of node, internode and leaf insertion in a nodal complex were performed on the basis of an analogue circuit of hydraulic resistances, where the hydraulic resistance of the node was divided into halves at the leaf insertion point. From measurements with Epipremnum aureum Bunt., Cucumis sativus L. and Zea mays L., it was indicated that hydraulic conductance of a leaf insertion was significantly lower than those of node and internode. Z. mays with the thickest stem had the highest hydraulic conductance of the internode. On the other hand, the stem-area specific, hydraulic conductances of node and internode were the highest in C. sativus with the thinnest stem and the large leaf.

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For individual evaluations of gas exchange parameters on adaxial and abaxial leaf surfaces, the Parkinson leaf cuvette (PP Systems. Ltd., UK) was improved by providing individual air paths to the respective upper (adaxial) and lower (abaxial) leaf cuvettes, where air current in each cuvette was also adjustable independently. The performance of the improved cuvette system was examined by using a wetted filter paper and a cucumber leaf. The three different modes of measurement, i.e. the upper cuvette mode, the lower cuvette mode and the both cuvettes mode, were selected successively, and leaf boundary layer conductance on each surface was arbitrarily adjusted in the range of 0.3 mol m-2s-1 to 1.0 mol m-2s-1. The heterogeneity between adaxial and abaxial surfaces of the cucumber leaf was found in gas exchange parameters such as stomatal conductance and rates of transpiration and photosynthesis, and further stomatal response to air current was revealed quantitatively by change in stomatal conductance.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：INTERNATIONAL SOCIETY HORTICULTURAL SCIENCE  

Dynamics of fruit growth and photoassimilate translocation in tomato plants (Lycopersicon esculentum Mill.) as affected by irradiation, air temperature and water deficit were analyzed with reference to water relations, respiration and photosynthesis in fruits and leaves. A multiple chamber gas exchange system for intact fruits and leaves was newly developed for on-line measurements of transpiration, respiration and photosynthesis. Fruit growth rate and pedicel sap fluxes through phloem and xylem were evaluated on-line by applying a pair of laser sensors and the heat-ring method. Furthermore, photoassimilate flux through a pedicel was evaluated on the basis of sugar balance in ethylenediaminetetraacetic acid solution into which the cut end of the pedicel was immersed. Fruit expansive growth was attributed to 80% of the pedicel sap flux, while 20% of the sap flux was lost by transpiration from the fruit (pedicel, calyx and berry). Irradiation and temperature rise in the daytime activated leaf photosynthesis, fruit respiration and phloem and xylem sap fluxes, which resulted in remarkable increases in fruit growth and photoasssimilate translocation in the daytime. Tn particular, the activated fruit respiration contributed to fruit growth and photoassimilate accumulation through energy-dependent postphloem transport in the fruit. Water deficit brought depressions in fruit growth and photoassimilate translocation with decreases in phloem and xylem sap fluxes, fruit respiration and leaf photosynthesis, where sap backflow through xylem and fruit shrinkage were also found. Thus, the methodologies newly developed in this study can be useful for obtaining quantitative information on dynamics of fruit growth and photoassimilate translocation, which is essential for the optimization of greenhouse environment to improve yield and quality of tomato fruits.

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Language：English   Publisher：Kyushu University  

Root xylem sap exuded from the decapitated stem stumps of tomato plants (Lycopersicon esculentum Mill.) was collected in the daytime and the nighttime, and dependence of calcium uptake on water absorption and respiration in the tomato roots is examined by analyzing exudation rate (JW; μLs-1), calcium concentration ([Ca2+]; mmol L-1) in the xylem sap and root calcium uptake rate (J(Ca); nmol s-1) in the root exudation. JW from the stem slump was about one third of transpiration rate from the whole shoot before decapitation and was kept two to five times higher in the daytime than in the nighttime. The xylem sap [Ca2+] was about 3 to 4.5 times higher than that of the nutrient solution in the hydroponic pot, and the xylem sap [Ca2+] in the daytime was 1.5 times higher than that in the nighttime. Consequently, J(Ca) in the daytime was 3 to 5.5 times higher than that in the nighttime. The daytime higher J(Ca) was depressed in the restrictedly water absorbing plant, and the restriction of root respiration in the daytime lowered the xylem sap [Ca2+], which resulted in significant depression in J(Ca). Furthermore, the lower J(Ca) in the nighttime was not enhanced by activating the nighttime root respiration. Thus, the daytime root calcium uptake was regulated by both of the water absorption and the respiration in roots, and the nighttime root respiration was not a rate-limiting factor for the lower calcium uptake in the nighttime. The observed dependence of calcium uptake on water absorption and respiration in roots was explained in relation to the important role of the root endodermis.

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Language：English   Publisher：Kyushu University  

Temperature effect on postphloem transport in tomato fruits was analyzed by measuring fruit growth rate, pedicel sugar flux and fruit respiratory CO2 efflux under changes in air temperature around fruits. Dynamic responses of fruit growth rate and pedicel sugar flux to temperature change around fruits were clearly found to be associated with change in fruit respiration. Fruit growth rate and pedicel sugar flux were remarkably enhanced with fruit respiration by temperature rise around fruits, where those Q10 values between 20°C and 30°C distributed around 2.3. These enhancements in fruit growth and sugar translocation by the temperature rise were not found in the truss with the respiration-inhibited fruits. From these results, it can be suggested that respiration in tomato fruits contributes to the temperature effects on the expansive growth and the sugar accumulation through regulation of the energy-dependent process of the postphloem sugar transport in the fruits.

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A multiple chamber system was developed for on-line measurements of gas (CO2 and H2O) fluxes in intact fruits and leaflets of tomato plants, where fruit growth rate and pedicel sap flux can be also measured. By using the system for the simultaneous measurements with six plants, effect of water deficit on fruit growth was analyzed in relation to water balance and respiration in the fruits and to photosynthesis and transpiration in the leaflets. The water deficit caused drastic depression in fruit growth in the daytime, which was considered to be associated with depressions in pedicel sap flux, fruit respiration and leaf photosynthesis. Furthermore, sap backflow and fruit shrinkage corresponding to about 2% of the fruit volume were induced by rise in evaporative demand under the water deficit. These results suggest that the multiple chamber system developed can be applied to quantitative analyses of environmental effects on fruit growth, translocation and sink-source relationship in tomato plants.

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Language：Japanese  

DOI： 10.2525/ecb1963.36.159

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Language：English   Publisher：Kyushu University  

An improved evaluation of photoassimilate flux through a pedicel of tomato plant (Lycopersicon esculentum Mill.) was examined in an application of ethylenediaminetetraacetic acid (EDTA) solution for collecting phloem exudate, where the cut end of the pedicel was immersed into the EDTA solution bath in a vial held on the pedicel. A part of the solution in the vial loaded with phloem exudate was sampled at a certain interval by using a micro syringe, and just after every sampling the solution bath was replenished with the fresh EDTA solution to keep the initial volume. Sugar concentration in the sampled solution and volumes of the solutions sampled and replenished were measured, and then photoassimilate flux exuded through the pedicel during the successive samplings was evaluated by analysis of sugar balance in the solution bath, where backflow through the pedicel was taken into account. The chelate effect of the EDTA solution was kept reliable for about a whole day, and photoassimilate flux was most enhanced in the solution bath of 20 mM EDTA and under the larger rates of replenishment with the fresh EDTA. Dynamic changes in the photoassimilate flux caused by lighting and leaf excision were evaluated clearly at a short sampling interval of 20 min. The results suggest that the improved EDTA method can be applied to short term analysis of dynamics of phloem translocation affected by change in pressure potential gradient through phloem from source leaves to the pedicel.

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Language：English   Publisher：Kyushu University  

A system for on-line measurements of CO2 and H2O gas fluxes, pedicel sap flux and expansive growth in an intact tomato fruit was newly developed, where the gas fluxes in leaflets also can be measured. The system was composed of a fruit chamber,a leaf chamber, CO2 and H20 gas analyzing unit and an on-line computer. Furthermore a laser displacement sensors system was equipped in the fruit chamber for evaluating fruit expansive growth, and the pedicel sap flux was evaluated as sum of the H2O gas flux and the growth rate in the fruit. Diurnal dynamics as affected by light condition were observed in respiration, transpiration, pedicel sap flux and expansive growth in the immature intact fruit, which were clearly enhanced in the light. In fruit water balance, about 30% of the sap flux imported through the pedicel was lost by transpiration from the calyx and the berry, and the residual 70% contributed to fruit expansive growth. These results suggest that the on-line system developed is applicable to quantitative analyses of respiration, sap flux and water balance of an intact tomato fruit in environmental studies on fruit expansive growth and photoassimilate translocation.

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Diurnal changes in respiration, pedicel sap flux, water balance and expansive growth in a fruit of tomato plant (Lycopersicon esculentum Mill.) were analyzed in an artificial light growth chamber, where the fruit at the stage of rapid sugar accumulation was used. The higher respiration of the intact berry was clearly found under the light where the sap flux and the growth rate were kept higher, but darkening, removal of the calyx and excision of the pedicel brought the lower berry respiration with significant depression in the sap flux and the growth rate. Transpirational water loss from each of the berry and the calyx was only 10% and 20% of the imported sap flux, and the residual 70% of the imported sap flux contributed to expansive growth of the berry. From these results, it is conceivable that respiration of the tomato fruit at the stage of rapid sugar accumulation closely relates to the phloem sap flux which is responsible for sugar accumulation and expansive growth of the fruit.

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：CROP SCIENCE SOC JAPAN  

PCR amplification of cDNA prepared from the poly(A)(+) RNA of tuberous roots of sweet potato, using degenerate oligonucleotide primers based on highly conserved regions among sucrose synthase (EC 2. 4. 1. 13) reported previously, yielded a cDNA of 1,191 bp (IBSUS). The nucleotide sequence of IBSUS exhibited a high degree of homology with the corresponding regions of the potato sucrose synthase cDNA sequences (82 and 86% of identical nucleotides). Less homology (76 similar to 77%) was found in the monocotyledonous sequences (maize, rice and barley). The activity of sucrose synthase in the tuberous roots of sweet potato was higher than that in other parts, namely, leaf blades, petioles, stolons and fibrous roots. The activity of sucrose synthase in roots increased markedly following an increase in sucrose during development of the tuberous roots. Northern blot analysis using IBSUS as a probe revealed that a signal of sucrose synthase mRNA with a size of approximately 2.4 kb was present in petioles, stolons, fibrous roots and tuberous roots, and the levels of sucrose synthase mRNA in different parts and in the roots during development of tuberous roots were highly correlated with enzymatic activities. In petioles, an increase in sucrose concentration led to an increase in the activity of sucrose synthase.

DOI： 10.1626/jcs.66.624

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DOI： 10.2525/ecb1963.39.43

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DOI： 10.2525/ecb1963.39.53

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Language：English   Publisher：International Society for Horticultural Science  

Dynamics of fruit growth and photoassimilate translocation in tomato plants (Lycopersicon esculentum Mill.) as affected by irradiation, air temperature and water deficit were analyzed with reference to water relations, respiration and photosynthesis in fruits and leaves. A multiple chamber gas exchange system for intact fruits and leaves was newly developed for on-line measurements of transpiration, respiration and photosynthesis. Fruit growth rate and pedicel sap fluxes through phloem and xylem were evaluated on-line by applying a pair of laser sensors and the heat-ring method. Furthermore, photoassimilate flux through a pedicel was evaluated on the basis of sugar balance in ethylenediaminetetraacetic acid solution into which the cut end of the pedicel was immersed. Fruit expansive growth was attributed to 80% of the pedicel sap flux, while 20% of the sap flux was lost by transpiration from the fruit (pedicel, calyx and berry). Irradiation and temperature rise in the daytime activated leaf photosynthesis, fruit respiration and phloem and xylem sap fluxes, which resulted in remarkable increases in fruit growth and photoasssimilate translocation in the daytime. In particular, the activated fruit respiration contributed to fruit growth and photoassimilate accumulation through energy-dependent postphloem transport in the fruit. Water deficit brought depressions in fruit growth and photoassimilate translocation with decreases in phloem and xylem sap fluxes, fruit respiration and leaf photosynthesis, where sap backflow through xylem and fruit shrinkage were also found. Thus, the methodologies newly developed in this study can be useful for obtaining quantitative information on dynamics of fruit growth and photoassimilate translocation, which is essential for the optimization of greenhouse environment to improve yield and quality of tomato fruits.

DOI： 10.17660/ActaHortic.2000.534.8

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For individual evaluations of gas exchange parameters on adaxial and abaxial leaf surfaces, the Parkinson leaf cuvette (PP Systems. Ltd., UK) was improved by providing individual air paths to the respective upper (adaxial) and lower (abaxial) leaf cuvettes, where air current in each cuvette was also adjustable independently. The performance of the improved cuvette system was examined by using a wetted filter paper and a cucumber leaf. The three different modes of measurement, i.e. the upper cuvette mode, the lower cuvette mode and the both cuvettes mode, were selected successively, and leaf boundary layer conductance on each surface was arbitrarily adjusted in the range of 0.3 mol m-2s-1 to 1.0 mol m-2s-1. The heterogeneity between adaxial and abaxial surfaces of the cucumber leaf was found in gas exchange parameters such as stomatal conductance and rates of transpiration and photosynthesis, and further stomatal response to air current was revealed quantitatively by change in stomatal conductance.

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Root xylem sap exuded from the decapitated stem stumps of tomato plants (Lycopersicon esculentum Mill.) was collected in the daytime and the nighttime, and dependence of calcium uptake on water absorption and respiration in the tomato roots is examined by analyzing exudation rate (Jw; μLs^<-1>), calcium concentration ([Ca^<2+>]; mmol L^<-1>) in the xylem sap and root calcium uptake rate (JCa; nmol s^<-1>) in the root exudation. Jw from the stem stump was about one third of transpiration rate from the whole shoot before decapitation and was kept two to five times higher in the daytime than in the nighttime. The xylem sap [Ca^<2+>] was about 3 to 4.5 times higher than that of the nutrient solution in the hydroponic pot, and the xylem sap [Ca^<2+>] in the daytime was 1.5 times higher than that in the nighttime. Consequently, JCa in the daytime was 3 to 5.5 times higher than that in the nighttime. The daytime higher JCa was depressed in the restrictedly water absorbing plant, and the restriction of root respiration in the daytime lowered the xylem sap [Ca^<2+>], which resulted in significant depression in JCa. Furthermore, the lower JCa in the nighttime was not enhanced by activating the nighttime root respiration. Thus, the daytime root calcium uptake was regulated by both of the water absorption and the respiration in roots, and the nighttime root respiration was not a rate-limiting factor for the lower calcium uptake in the nighttime. The observed dependence of calcium uptake on water absorption and respiration in roots was explained in relation to the important role of the root endodermis.

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DOI： 10.2525/ecb1963.36.159

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In production of Satsuma mandarin (Citrus unshiu Marc.) grown on greenhouse cultivation, management of day and night temperature and soil water content is important to improve yield and quality of the fruits. In this study, in order to optimize greenhouse environment for Satsuma mandarin production, we conducted dynamic analysis of effects of soil water content, day temperature and night temperatures on fruit growth and mass accumulation through phloem and xylem into a fruit.

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