記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.5702/massspectrometry.a0092

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

DOI： 10.1002/agj2.20381

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その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/agj2.20381

掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

DOI： 10.1002/agj2.20309

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Although a loss of healthy pollen grains induced by metabolic heat responses has been indicated to be a major cause of heat-induced spikelet sterility under global climate change, to date detailed information at pollen level has been lacking due to the technical limitations. In this study, we used picolitre pressure-probe-electrospray-ionization mass spectrometry (picoPPESI-MS) to directly determine the metabolites in heat-treated single mature pollen grains in two cultivars, heat-tolerant cultivar, N22 and heat-sensitive cultivar, Koshihikari. Heat-induced spikelet fertility in N22 and Koshihikari was 90.0% and 46.8%, respectively. While no treatment difference in in vitro pollen viability was observed in each cultivar, contrasting varietal differences in phosphatidylinositol (PI)(34:3) have been detected in mature pollen, together with other 106 metabolites. Greater PI content was detected in N22 pollen regardless of the treatment, but not for Koshihikari pollen. In contrast, there was little detection for phosphoinositide in the single mature pollen grains in both cultivars. Our findings indicate that picoPPESI-MS analysis can efficiently identify the metabolites in intact single pollen. Since PI is a precursor of phosphoinositide that induces multiple signaling for pollen germination and tube growth, the active synthesis of PI(34:3) prior to germination may be closely associated with sustaining spikelet fertility even at high temperatures.

DOI： 10.1038/s41598-020-58869-9

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掲載種別：研究論文（学術雑誌）   出版者・発行元：Royal Society of Chemistry (RSC)  

<p>In the previous work, sheath-flow probe electrospray ionization (sfPESI) equipped with a touch sensor was developed for conducting samples.</p>

DOI： 10.1039/d0ay00778a

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jafc.9b06489

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1104/pp.19.00743

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jafc.8b06424

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：OXFORD UNIV PRESS  

Heat-induced chalkiness of rice grains is a major concern for rice production, particularly with respect to climate change. Although the formation of chalkiness in the endosperm is suppressed by nitrogen, little is known about the cell-specific dynamics of this process. Here, using picolitre pressure-probe electrospray-ionization mass spectrometry together with transmission electron microscopy and turgor measurements, we examine heat-induced chalkiness in single endosperm cells of intact rice seeds produced under controlled environmental conditions. Exposure to heat stress decreased turgor pressure and increased the cytosolic accumulation of sugars, glutathione, and amino acids, particularly cysteine. Heat stress also led to a significant enlargement of the protein storage vacuoles but with little accumulation of storage proteins. Crucially, this heat-induced partial arrest of amyloplast development led to formation of chalkiness. Whilst increased nitrogen availability also resulted in increased accumulation of amino acids, there was no decrease in turgor pressure. The heat-induced accumulation of cysteine and glutathione was much less marked in the presence of nitrogen, and storage proteins were produced without chalkiness. These data provide important information on the cell dynamics of heat acclimation that underpin the formation of chalkiness in the rice endosperm. We conclude that rice seeds employ multiple strategies to mitigate the adverse effects of heat stress in a manner that is dependent on nitrogen availability, and that the regulation of protein synthesis may play a crucial role in optimizing organelle compartmentation during heat adaption.

DOI： 10.1093/jxb/ery427

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier Ltd  

Rapid, direct, on-site and noninvasive food analysis is strongly needed for quality control of food. To satisfy this demand, the technique of dipping probe electrospray ionization/mass spectrometry (dPESI/MS) was developed. The sample surface was pricked with a fine acupuncture needle and a sample of ∼200 pL was captured at the needle tip. After drying the sample, the needle tip was dipped into the solvent for ∼50 ms and was moved upward. A high-voltage was applied to the needle to generate electrospray when the needle reached the highest position, and mass spectra were measured with a time-of-flight mass spectrometer. For evaluation of the method, the technique was used to analyze foods such as vegetables, salmon flesh, cow's milk, yogurt, and soy-bean milk. The detected major ions for cow's milk and yogurt were [(Lac)n + Ca]2+ with n = 1–6 (where (Lac) is lactose), indicating that Ca2+ is tightly bound by Lac molecules.

DOI： 10.1016/j.foodchem.2018.04.003

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掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s13361-018-2062-3

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s00425-018-2975-x

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：John Wiley and Sons Ltd  

Rationale: Probe electrospray ionization (PESI) is only applicable to liquid or wet samples. In this study, a sheath-flow PESI method for remote sampling mass spectrometry that can be applied to dry samples was developed. Methods: An acupuncture needle (0.12 mm outer diameter, 700 nm tip diameter) was inserted into a gel-loading tip with a 0.1 mm protrusion out of the tip. Analytes were extracted by filling the latter tip with solvent and softly touching the sample surface for a short time (&lt
1 s). A high voltage was applied to the acupuncture needle, and mass spectra of analytes were obtained by self-aspirating electrospray. Results: Dry samples, such as lines of ballpoint pen ink on paper, pharmaceutical tablets, instant coffee, brown rice, and narcotics, gave strong ion signals. The sample carryover was negligible. The sequential electrospray was observed to be similar to conventional PESI. The limits of detection (LODs) for morphine and rhodamine B were found to be of the order of picograms. Conclusions: Because of its simplicity and versatility, sheath-flow PESI is a promising technique for on-site and nondestructive profile analysis of dry samples with bulky and complicated shapes, with a spatial resolution of ~0.3 mm.

DOI： 10.1002/rcm.8045

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ROYAL SOC CHEMISTRY  

The temporal profiles of ion signals were measured for probe electrospray ionization (PESI) and nanoelectrospray ionization (nESI) by changing the pulse width of the high voltage applied to the emitters (PESI: 0.12 mm o. d. and 700 nm tip diameter metal needle; nESI: metal-coated 15 mm i. d. silica capillary). The ion signals started to be detected at similar to 400 ms and 5 ms, respectively, for PESI and nESI (solution: 10 (- 5) M cytochrome c and 0.1- 1% acetic acid in H2O/MeOH (1/1)). With the addition of 10 mM ammonium acetate in 10 (-5) M cytochrome c solution, the threshold for the signal appearance became about one order of magnitude longer with weaker signal intensities than those for acidic solutions. PESI was applied to real samples such as mayonnaise, natto (fermented soybeans), tomato ketchup and salmon eggs. Marked sequential electrospray was observed for these samples.

DOI： 10.1039/c7ay01275f

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER SCIENCE BV  

Fluorene and 9,9-dialkyl fluorenes were examined by electrospray droplet impact/secondary ion mass spectrometry (EDI/SIMS). From the major peaks: M+center dot, [M + H](+), [M+, and [M - R - (R - H)](+) detected by EDI/SIMS, information on the molecular masses (M) and the side chains (R) could be obtainedfor dioctyl-, dihexyltri-, dioctyltri- and dihexylheptafluorenes. Despite the different alkyl substituents, dihexyltrifluorene (C75H98) and dioctyltrifluorene (C87H122) gave similar fragment-ion distribution patterns with the common peak values at m/z 339 and 517 in the two envelopes. This suggests that the fragmentation paths are similar for these two compounds. The ions with m/z 339 and 517 were tentatively assigned asC(27)H(15)(+) and C41H25+ in which all the alkyl substituents (R) were eliminated. Fragmentation paths of protonated fluorenes were examined by DFT calculations.The reaction paths of the elimination of side two alkyl chains to give fluorenyl cations as the final products were postulated for 9,9-dimethylfluorene and 9,9-dioctylfluorene.

DOI： 10.1016/j.ijms.2017.05.006

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PUBLIC LIBRARY SCIENCE  

Grain filling ability is mainly affected by the translocation of carbohydrates generated from temporarily stored stem starch in most field crops including rice (Oryza sativa L.). The partitioning of non-structural stem carbohydrates has been recognized as an important trait for raising the yield ceiling, yet we still do not fully understand how carbohydrate partitioning occurs in the stems. In this study, two rice subspecies that exhibit different patterns of nonstructural stem carbohydrates partitioning, a japonica-dominant cultivar, Momiroman, and an indica-dominant cultivar, Hokuriku 193, were used as the model system to study the relationship between turgor pressure and metabolic regulation of non-structural stem carbohydrates, by combining the water status measurement with gene expression analysis and a dynamic prefixed C-13 tracer analysis using a mass spectrometer. Here, we report a clear varietal difference in turgor-associated starch phosphorylation occurred at the initiation of non-structural carbohydrate partitioning. The data indicated that starch degradation in Hokuriku 193 stems occurred at full-heading, 5 days earlier than in Momiroman, contributing to greater sink filling. Gene expression analysis revealed that expression pattern of the gene encoding alpha-glucan, water dikinase (GWD1) was similar between two varieties, and the maximum expression level in Hokuriku 193, reached at full heading (4 DAH), was greater than in Momiroman, leading to an earlier increase in a series of amylase-related gene expression in Hokuriku 193. In both varieties, peaks in turgor pressure preceded the increases in GWD1 expression, and changes in GWD1 expression was correlated with turgor pressure. Additionally, a threshold is likely to exist for GWD1 expression to facilitate starch degradation. Taken together, these results raise the possibility that turgor-associated starch phosphorylation in cells is responsible for the metabolism that leads to starch degradation. Because the two cultivars exhibited remarkable varietal differences in the pattern of non-structural carbohydrate partitioning, our findings propose that the observed difference in grain-filling ability originated from turgor-associated regulation of starch phosphorylation in stem parenchyma cells. Further understanding of the molecular mechanism of turgor-regulation may provide a new selection criterion for breaking the yield barriers in crop production.

DOI： 10.1371/journal.pone.0181272

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER SCIENCE BV  

Direct and rapid trace-level gas analysis is highly needed in various fields such as safety and security, quality control, food analysis, and forensic medicine. In many cases, the real samples are bulky and are not accessible to the space-limited ion source of the mass spectrometer. In order to circumvent this problem, we developed an airtight atmospheric-pressure chemical ionization (APCI) ion source equipped with a flexible 1-m-long, 2-mm-i.d. PTFE sniffing tube. The ambient air bearing sample gas was sucked into the heated PTFE tube (130 degrees C) and was transported to the air-tight ion source without using any extra pumping system or a Venturi device. Analytes were ionized by an ac corona discharge located at 1.5 mm from the inlet of the mass spectrometer. By using the airtight ion source, all the ionized gas in the ion source was introduced into the vacuum of the mass spectrometer via only the evacuation of the mass spectrometer (1.6 l min(-1)). Sub-pg limits of detection were obtained for carbaryl and trinitrotoluene. Owing to its flexibility and high sensitivity, the sniffing tube coupled with a mass spectrometer can be used as the stethoscope for the high-sensitive gas analysis. The experimental results obtained for drugs, hydrogen peroxide and small alkanes were discussed by DFT calculations. (C) 2017 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.aca.2017.03.044

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：BIOMED CENTRAL LTD  

Background: Reduction in rice yield caused by high temperature-induced spikelet sterility has been a serious concern in rice production. To date, several screening methods have been used, although their reproducibility is sometimes poor due to artifacts mainly caused by varietal differences in heading dates and panicle heights (i.e., the distance from the lamps).
Methods: We have developed a novel assay system for heat-induced spikelet sterility by using artificial rice paddies in phytotrons to conduct a highly reproducible assay throughout a year. Plants restricted to the main culm were treated under a series of heat conditions, and height uniformity of each plant was ensured by using height-adjustable pots.
Results: Results suggested that a 3-day heat treatment of 35 degrees C-day/29 degrees C-night cycles was the most suitable condition. Under the treatment, two distinct groups were identified among nine heat tolerant cultivars, with no varietal difference in panicle temperature, indicating that the system is capable of eliminating the varietal difference in panicle temperature.
Conclusions: It is concluded that the assay system would be a powerful tool for selecting heat tolerant varieties, as well as the analysis of genetic factors from various cultivars, eliminating potential artifacts.

DOI： 10.1186/s13007-017-0185-3

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.5702/massspectrometry.S0059

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/jms.3890

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER SCIENCE BV  

Gaseous ions generated by the ultrasonic atomization of liquids were measured by mass spectrometry for the first time. The aqueous solutions of 10(-5) M drugs, peptides, proteins, surface-active agents, rhodamine B, explosives saccharides, and polyethylene glycol were supplied to the edge of the ultrasonically-vibrating blade (22 kHz) through the 20 mu m i.d. silica capillary with the flow rate of 1 mu L/min. The analytes were detected mainly as sodiated, protonated, or deprotonated forms. The ion signal intensities were highly dependent on the surface-activity values of the analyte ions, i.e., the higher the surface-activity values, the stronger the ion signal intensities. The addition of 0.5% acetic acid in the solutions led to the drastic decrease in ion signal intensities. (C) 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ijms.2016.11.009

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

Ion/molecule reactions of saturated hydrocarbons (n-hexane, cyclohexane, n-heptane, n-octane and isooctane) in 28-TorrN(2) plasma generated by a hollow cathode discharge ion source were investigated using an Orbitrap mass spectrometer. It was found that the ions with [M+14](+) were observed as the major ions (M: sample molecule). The exact mass analysis revealed that the ions are nitrogenated molecules, [M+N](+) formed by the reactions of N-3(+) with M. The reaction, N-3(+) + M[M+N](+) + N-2, were examined by the density functional theory calculations. It was found that N-3(+) abstracts the H atom from hydrocarbon molecules leading to the formation of protonated imines in the forms of RRCNH2+ (i.e. C-H bond nitrogenation). This result is in accord with the fact that elimination of NH3 is the major channel for MS/MS of [M+N](+). That is, nitrogen is incorporated in the C-H bonds of saturated hydrocarbons. No nitrogenation was observed for benzene and acetone, which was ascribed to the formation of stable charge-transfer complexes benzeneN(3)(+) and acetoneN(3)(+) revealed by density functional theory calculations. Copyright (c) 2016 John Wiley & Sons, Ltd.

DOI： 10.1002/jms.3765

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER SOC AGRONOMY  

Climate change increases the occurrence of chalky rice (Oryza sativa L.) through frequent extreme weather conditions, such as high temperature and low radiation. The objective of this study was to examine the possibility of developing prediction methods for estimating the occurrence of a major type of chalky rice, the milky-white rice. The methods evaluated the chalky patterns on the transverse section of premature grains by visual inspection or by employing a newly developed image analyzer. The predicted grain rates of milky-white rice using the above-mentioned method(s) as well as two other methods using a grain scanner, were compared with periodically sampled grains approaching maturity under shade treatments at Kagoshima and Fukuoka, Japan. The grain rates predicted using visual inspection and the developed analyzer at 6 to 7 d before maturity (DBM) and 9 to 10 DBM, were positively correlated with the target grain rates of milky-white rice obtained at maturity; R-2 was 0.906 (p &lt; 0.01) to 0.964 (p &lt; 0.001), and the RMSE value ranged from 2.00 to 6.10, at both the DBMs. In the methods employing the grain scanner, the correlations between the predicted and target grain rates at the same DBMs were lower; R-2 was 0.556 (p = 0.054) to 0.777 (p &lt; 0.01), the RMSE value was between 7.86 and 12.03. Thus, the methods using transverse section of premature grains developed in this study could be applied for predicting the occurrence of milky-white rice a week to 10 DBM.

DOI： 10.2134/agronj2015.0444

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER CHEMICAL SOC  

In this report, we developed the pressure probe electrospray ionization-mass spectrometry with internal electrode capillary (IEC-PPESI-MS) which enables high spatial-resolution cell sampling, precise postsampling manipulation, and high detection sensitivity. Using this technique, a comparative in situ single-cell metabolite profiling of stalk and glandular cells, the two adjacent cell types comprising a trichome unit in tomato plants (Solanum lycopersicum L.), were performed to clarify the extent of Metabolic differentiation between two cell types as well as among different types of trichomes. Owing to high. sensitivity of the system, less than a picoliter cell sap from a single stalk cell sufficiently yielded a number of peaks of amino acids, organic acids, carbohydrates, and flavonoids. The minimal cell sap removal from a stalk cell without severe disturbance of trichome structure enabled sequential analysis of adjacent glandular cell on the same trichome, which showed the presence of striking differences in metabolite compositions between two adjacent cell types. Comparison among different types of trichome also revealed significant variations in metabolite profiles, particularly in flavonoids and acyl sugars compositions. Some metabolites were found only in specific cell types or particular trichome types. Although extensive metabolomics analysis of glandular cells of tomato trichomes has been previously documented, this is the first report describing cell-to-cell variations in metabolite compositions of stalk and glandular cells as well as in different trichome types. Further application of this technique may provide new insights into distinct metabolism in plant cells displaying variations in shape, size, function and physicochemical properties.

DOI： 10.1021/acs.analchem.5b03366

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：OXFORD UNIV PRESS  

Along with sugar accumulation and colour development, softening is an important physiological change during the onset of ripening in fruits. In this work, we investigated the relationships among major events during softening in grape (Vitis vinifera L.) by quantifying elasticity in individual berries. In addition, we delayed softening and inhibited sugar accumulation using a mechanical growth-preventing treatment in order to identify processes that are sugar and/or growth dependent. Ripening processes commenced on various days after anthesis, but always at similarly low elasticity and turgor. Much of the softening occurred in the absence of other changes in berry physiology investigated here. Several genes encoding key cell wall-modifying enzymes were not up-regulated until softening was largely completed, suggesting softening may result primarily from decreases in turgor. Similarly, there was no decrease in solute potential, increase in sugar concentration, or colour development until elasticity and turgor were near minimum values, and these processes were inhibited when berry growth was prevented. Increases in abscisic acid occurred early during softening and in the absence of significant expression of the V. vinifera 9-cis-epoxycarotenoid dioxygenases. However, these increases were coincident with decreases in the abscisic acid catabolite diphasic acid, indicating that initial increases in abscisic acid may result from decreases in catabolism and/or exogenous import. These data suggest that softening, decreases in turgor, and increases in abscisic acid represent some of the earliest events during the onset of ripening. Later, physical growth, further increases in abscisic acid, and the accumulation of sugar are integral for colour development.

DOI： 10.1093/jxb/erv483

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ROYAL SOC CHEMISTRY  

Friction plays an important role in desorption and/or ionization of nonvolatile compounds in mass spectrometry, e.g., sonic spray, easy ambient sonic-spray ionization, solvent-assisted inlet ionization, desorption electrospray, etc. In our previous work, desorption of low molecular weight compounds induced by solid/solid dynamic friction was studied. The objective of this work was to investigate desorption of low-volatility compounds induced by liquid/solid friction. Water/methanol (1/1) microdroplets with similar to 30 mu m in diameter were generated by using a piezoelectric microdroplet generator. They were injected to analytes deposited on the flat surface of a blade vibrating ultrasonically with the frequency of 40 kHz. Neutral molecules desorbed from the blade were ionized by a helium dielectric barrier discharge (DBD), generating strong signals for samples including drugs, explosives, and insecticides. These signals were not detected when either the blade vibrator or the piezoelectric microdroplet generator was off. In contrast, for ionic compounds such as 1-butyl-3-methylimidazolium bis(trifluoro-methylsulfonyl) imide, p-chlorobenzyl pyridinium chloride, and rhodamine B, strong ion signals were obtained when the vibrator and droplet generator were on, but DBD was off. Sub-nanogram limits of detection were attained for lowvolatility compounds.

DOI： 10.1039/c5an02215k

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：TAYLOR & FRANCIS LTD  

Climate change has been an increasingly significant factor behind fluctuations in the yield and quality of rice (Oryza sativa L.), particularly regarding chalky (white-back, basal-white, and milky-white) grain, immature thin grain, and cracked grain. The development and use of heat-tolerant varieties is an effective way to reduce each type of grain damage based on the existence of each varietal difference. Cultivation methods that increase the available assimilate supply per grain, such as deep-flood irrigation, are effective for diminishing the occurrence of milky-white grains under high temperature and low solar radiation conditions. The application of sufficient nitrogen during the reproductive stage is important to reduce the occurrence of most heat damage with the exception of milky-white grain. In regard to developing measures for heat-induced poor palatability of cooked rice, a sensory parameter, the hardness/adhesion ratio may be useful as an indicator of palatability within a relatively wide air-temperature range during ripening. Methods for heat damage to rice can be classified as either avoidance or tolerance measures. The timing of the measures is further divided into preventive and prompt types. The use of heat-tolerant varieties and late transplanting are preventive measures, whereas the application of sufficient nitrogen as a top dressing and irrigation techniques during the reproductive stage are prompt types which may function to lower the canopy temperature by enhancing evapotranspiration. Trials combining the different types of techniques will contribute towards obtaining more efficient and steady countermeasures against heat damage under conditions of climate change.

DOI： 10.1080/1343943X.2015.1128114

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

RationaleIn electrospray droplet impact (EDI) developed in our laboratory, an atmospheric pressure electrospray source has been used. To increase the ion beam intensity and reduce the evacuation load, a vacuum electrospray cluster ion source using a silica capillary was developed.
MethodsA silica capillary with a tip inner diameter of 8 mu m was used for vacuum electrospray using aqueous 10% methanol. To stabilize the flow rate of the liquid for nano-electrospray, a home-made constant pressure liquid pump was also developed.
ResultsBy using the silica tip nano-electrospray emitter and a constant pressure pump, stable electrospray with flow rate of 22nL/min was realized without using any heating system such as laser irradiation. Comparative study of mass spectra obtained by atmospheric pressure EDI (A-EDI) and vacuum EDI (V-EDI) was made for various samples such as thermometer molecule, peptide, polystyrene, Alq(3), NPD, C-60, indium, and SiO2. V-EDI showed slightly milder ionization than A-EDI.
ConclusionsBecause V-EDI gave higher target current (5-10nA) than A-EDI (a few nA at most), V-EDI secondary ion mass spectrometry (SIMS) would be a useful technique for the surface and interface analysis. Copyright (c) 2015 John Wiley & Sons, Ltd.

DOI： 10.1002/rcm.7240

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

In our previous paper, it was suggested that metal fluorides may be useful as cationization matrices in Electrospray droplet impact/SIMS. In this work, NaF and AgF were used as the cationization matrices for cyclodextrin (CD), polyethylene glycol (PEG), polystyrene (PS), garlic juice, and sliced raw rice. EDI mass spectra were measured without and with the use of matrices. Enhancement of ion abundances of [M+Na](+) for CD and PEG with NaF matrix and that of [M+Ag](+) for PS with AgF matrix were observed. However, the addition of matrices was not effective for the cationization of garlic juice and sliced raw rice samples. This may be due to the Coulombic repulsion of the reagent ions of Na+ or Ag+ with the preformed K+ adducts of oligosaccharides already present in the samples. Copyright (c) 2015 John Wiley & Sons, Ltd.

DOI： 10.1002/sia.5782

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：PUBLIC LIBRARY SCIENCE  

Foehn-like extreme hot and dry wind conditions (34 degrees C &gt;2.5 kPa vapor pressure deficit, and 7 m s(-1)) strongly affect grain quality in rice (Oryza sativa L.). This is a current concern because of the increasing frequency and intensity of combined heat and water-deficit stress under climate change. Foehn-induced dry wind conditions during the grain-filling stage increase ring-shaped chalkiness as a result of spatiotemporal reduction in starch accumulation in the endosperm, but kernel growth is sometimes maintained by osmotic adjustment. Here, we assess the effects of dry wind on chalky ring formation in environmentally controlled growth chambers. Our results showed that hot and dry wind conditions that lasted for &gt;24 h dramatically increased chalky ring formation. Hot and dry wind conditions temporarily reduced panicle water potential to -0.65 MPa; however, kernel growth was maintained by osmotic adjustment at control levels with increased transport of assimilate to the growing kernels. Dynamic tracer analysis with a nano-electrospray-ionization Orbitrap mass spectrometer and quantitative polymerase chain reaction analysis revealed that starch degradation was negligible in the short-term treatment. Overall expression of starch synthesis-related genes was found to be down-regulated at moderately low water potential. Because the events observed at low water potential preceded the packing of starch granules in cells, we concluded that reduced rates of starch biosynthesis play a central role in the events of cellular metabolism that are altered at osmotic adjustment, which leads to chalky ring formation under short-term hot and dry wind conditions.

DOI： 10.1371/journal.pone.0110374

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER SOC PLANT BIOLOGISTS  

Using the automated cell pressure probe, small and highly reproducible hydrostatic pressure clamp (PC) and pressure relaxation (PR) tests (typically, applied step change in pressure = 0.02 MPa and overall change in volume = 30 pL, respectively) were applied to individual Tradescantia virginiana epidermal cells to determine both exosmotic and endosmotic hydraulic conductivity (L-p(OUT) and L-p(IN), respectively). Within-cell reproducibility of measured hydraulic parameters depended on the method used, with the PR method giving a lower average coefficient of variation (15.2%, 5.8%, and 19.0% for half-time, cell volume [V-o], and hydraulic conductivity [L-p], respectively) than the PC method (25.4%, 22.0%, and 24.2%, respectively). V-o as determined from PC and PR tests was 1.1 to 2.7 nL and in the range of optically estimated V-o values of 1.5 to 4.9 nL. For the same cell, V-o and L-p estimates were significantly lower (about 15% and 30%, respectively) when determined by PC compared with PR. Both methods, however, showed significantly higher L-p(OUT) than L-p(IN) (L-p(OUT) and L-p(IN) congruent to 1.20). Because these results were obtained using small and reversible hydrostatically driven flows in the same cell, the 20% outward biased polarity of water transport is most likely not due to artifacts associated with unstirred layers or to direct effects of externally applied osmotica on the membrane, as has been suggested in previous studies. The rapid reversibility of applied flow direction, particularly for the PR method, and the lack of a clear increase in L-p(OUT)/L-p(IN) over a wide range of L-p values suggest that the observed polarity is an intrinsic biophysical property of the intact membrane/protein complex.

DOI： 10.1104/pp.113.231688

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

DOI： 10.1111/j.1469-8137.2012.04244.x

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：CROP SCIENCE SOC AMER  

Because forage rice (Oryza sativa L.) must be cost-competitive with other forage crops, high grain yield is essential. The objective of the present study was to determine the effects of planting density (11, 25, or 100 hills m(-2)) and N application method (the 79-21N method, with 79% of the N applied before the panicle initiation stage and 21% after, or the 36-64N method, 36% before and 64% after) on grain yield and its components in the cultivar Mizuhochikara, which produces an unusually large number of spikelets per square meter. Grain yield was not different between N application methods but increased from 799 g m(-2) to 870 g m(-2) with increasing planting density. The number of spikelets per square meter was not strongly influenced by the planting densities. The percentage of filled spikelets and the 1000-grain weight was higher at 100 and 25 hills m(-2) than at 11 hills m(-2). The amount of nonstructural carbohydrate (NSC) in the leaf sheaths plus stems per square meter at the full heading stage was larger at 100 and 25 hills m(-2) than at 11 hills m(-2). The percentages of both primary and secondary spikelets increased with increasing planting density, whereas that of tertiary spikelets decreased. Grain weight per spikelet was generally higher at primary and secondary spikelets than at tertiary spikelets. At each position in the panicle, grain weight per spikelet was heavier at 100 and 25 hills m(-2) than at 11 hills m(-2). Thus, dense planting may increase the grain yield, the percentage of filled spikelets, and the 1000-grain weight by increasing NSC at full heading stage and decreasing the number of tertiary spikelets even at a large number of spikelets per square meter in Mizuhochikara.

DOI： 10.2135/cropsci2011.02.0071

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：OXFORD UNIV PRESS  

This study reports the first observations indicating the spatiotemporal relationships among genetic and physiological aspects of ripening in the berry of Vitis vinifera. At the onset of ripening in the red flesh variety Alicante Bouschet, colour development began in the flesh at the stylar end of the fruit and progressed toward the pedicel end flesh and into the skin. Tissue solute potential and cell turgor also decreased first in the flesh. The decrease in flesh solute potential was due to accumulation of sugars, glucose and fructose, an accumulation that is integral to ripening. Expression of the anthocyanin biosynthesis-related genes VvMybA and VvUFGT was linearly related to the decrease in solute potential. Expression of VvMybA, and to a lesser extent VvUFGT, was correspondingly low in green tissue, higher in the red, stylar end flesh of berries beginning to ripen, and greatest in red berries. In contrast, expression of the abscisic acid biosynthesis-related genes VvNCED1 and VvNCED2 was not correlated with the other spatiotemporal aspects of the onset of ripening. These results, together with earlier work showing that sugar accumulation and acid loss also begin in the stylar flesh in other varieties, indicate that ripening in the grape berry originates in the stylar end flesh.

DOI： 10.1093/jxb/err150

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：CROP SCIENCE SOC AMER  

Foehn-induced dry wind during grain filling increased ring-shaped chalky kernels in rice (Oryza sativa L.) plants. The objective of this study was to determine physiological mechanisms of the occurrence of ring-shaped chalky kernels. Rice plants were subjected to water deficit in a paddy field after shade by applying dry high-speed wind. Additionally, a growth chamber experiment was conducted with plants in pots to measure the water status under the dry wind condition for 24 h by combining in situ turgor (Psi(p)) assay in developing endosperms with the water potential measurements. The dry (high vapor pressure deficit [VPD]) wind treatment produced the largest number of ring-shaped chalky kernels due to poor starch accumulation, compared with shade or low-VPD wind treatment. The inner endosperm cells, where a high frequency of chalkiness was observed, spatially maintained Psi(p) by osmotic adjustment before the chalky formation with no decline of grain weight. Dry wind reduced photosynthesis due to a partial stomatal closure after water deficit developed. However, these responses, including those related to the plant water status, returned to a level similar to those of the control plants in a day after the dry wind was stopped. We conclude that (i) Psi(p) maintenance by osmotic adjustment contributes to grain development under water deficit under foehn conditions and (ii) osmotic adjustment has a role in temporally inhibiting starch accumulation in endosperms, resulting in ring-shaped chalky kernels under foehn-induced water deficit conditions.

DOI： 10.2135/cropsci2010.08.0503

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担当区分：筆頭著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

The role of three tip fabrication methods and of tip size in cell pressure probe measurements was investigated. The stability over time of turgor pressure (P) in mesocarp cells of intact grape berries was determined for microcapillary tips of contrasting sizes and methods of production (micro-beveler, micro-grinder, and breaking) at contrasting depths below the berry epidermis. SEM images showed that breaking, and in some cases micro-grinding methods produced tips with irregular, fractured surfaces, compared to relatively smooth surfaces produced with microbeveling. Finely pointed glass microcapillaries were made with reproducibly small tip dimensions (i.d. &lt
5 μm) by using a jet-stream micro-beveler and a mass flow meter to continuously monitor pressurized (pneumatic) air flow from the tip during the beveling process. Optically determined tip i.d. was highly correlated (r2 = 0.99) to pneumatic tip conductance. Overall cell dimensions ranged from about 10 μm near the epidermis to over 100 μm at a depth of 2 mm. At shallow depths (&lt
250 μm), P was relatively instable (declined at - 0.035 MPa/min) when measured using large tips (i.d. &gt
5μm) and significantly more stable (-0.009 MPa/min) using small tips (i.d. &lt
5 μm). At deeper depths (&gt
250 μm), both tip sizes gave relatively stable P values (-0.007 and-0.004 MPa/min for large and small tips, respectively). For tips of comparable size, micro-beveling gave improved P stability compared to breaking, and an improved ability to measure cells closer to the epidermis compared to micro-grinding. Literature values for acceptability of P values as stable in higher plant cells range from-0.001 to-0.05 MPa/min. These data suggest that P stability might be influenced by both tip size/shape and cell dimensions, and that improved tip fabrication techniques should improve the stability and reproducibility of P measurements, particularly for small cells.

DOI： 10.2525/ecb.49.61

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：WILEY-BLACKWELL  

Among woody plants, grapevines are often described as highly vulnerable to water-stress induced cavitation with emboli forming at slight tensions. However, we found native embolism never exceeded 30% despite low xylem water potentials (Psi(x)) for stems of field grown vines. The discrepancy between native embolism measurements and those of previous reports led us to assess vulnerability curve generation using four separate methods and alterations (i.e. segment length and with/without flushing to remove embolism prior to measurement) of each. Centrifuge, dehydration and air-injection methods, which rely on measurement of percentage loss of hydraulic conductivity (PLC) in detached stems, were compared against non-invasive monitoring of xylem cavitation with nuclear magnetic resonance (NMR) imaging. Short segment air-injection and flushed centrifuge stems reached &gt; 90 PLC at Psi(x) of-0.5 and -1.5 MPa, respectively, whereas dehydration and long-segment air-injection measurements indicated no significant embolism at Psi(x) &gt; -2.0 MPa. Observations from NMR agreed with the dehydration and long segment air-injection methods, showing the majority of vessels were still water-filled at Psi(x) &gt; -1.5 MPa. Our findings show V. vinifera stems are far less vulnerable to water stress-induced cavitation than previously reported, and dehydration and long segment air-injection techniques are more appropriate for long-vesseled species and organs.

DOI： 10.1111/j.1365-3040.2010.02160.x

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1111/j.1399-3054.2009.01231.x

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACADEMIC PRESS INC ELSEVIER SCIENCE  

An automated cell pressure probe was designed to allow robust measurements of cellular water relations without the limitations caused by operator skill levels (rapid response time, good hand-eye coordination, and manual dexterity). The system was based upon a real-time (30 Hz) computer vision system that employed a radial basis function, artificial neural network using direct greyscale template matching for meniscus recognition and control. The system did not require any custom-built hardware but used readily available off-the-shelf components and was designed to be highly portable, scalable, and relatively simple to set up. The system was robust in the presence of debris or dust on or in the glass capillary, and for tapered capillary probes, tolerant of variations in contrast due to changes in the velocity or travel direction of the meniscus. The system was capable of controlling the pressure within +/-0.0005 MPa and could perform pressure-clamp experiments at +/-0.001 MPa or greater pressure steps. The automatic meniscus system recognition could accurately detect the meniscus location with a mean error of under 6 mu m and a standard deviation of less than 3.2 mu m. Mean errors in automatic volume estimation ranged from 0.07 to 0.6%, depending upon capillary diameter. (C) 2009 IAgrE. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.biosystemseng.2009.02.017

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：OXFORD UNIV PRESS  

Using a novel pressure membrane (PM) apparatus for the extraction of apoplastic fluid from field-grown grape (Vitis vinifera L.) berries, our hypothesis that significant apoplast solutes accumulate at the beginning of the ripening process (i.e. veraison), and that this accumulation might contribute to progressive berry softening due to a progressive loss of mesocarp cell turgor pressure (P) was tested. It was necessary to correct the solute potential (Psi(s)) of fluid collected with the PM for dilution due to the presence of a dead volume in the apparatus, but after correction, the Psi(s) obtained with the PM agreed with that obtained by low speed centrifugation. A clear decline in fruit apoplastic solute potential (psi A) began approximately 10 d prior to fruit coloration, and it was found to be coincident with a decline in mesocarp cell P and fruit elasticity (E). By late in fruit development when berry growth ceased (90 d after anthesis), both apoplast and fruit Psi(s) reached almost -4 MPa. These results support the hypothesis that a decrease in psi SA is responsible for the observed loss in mesocarp cell P, and is the mechanistic cause of berry softening.

DOI： 10.1093/jxb/erp050

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SPRINGER  

In Vitis vinifera L. berries, the onset of ripening (known as "veraison") involves loss of turgor (P) in the mesocarp cells. We hypothesized that P loss was associated with an accumulation of apoplastic solutes in mesocarp tissue prior to veraison. Apoplastic sap was extracted from the mesocarp by centrifugation at the appropriate gravity to measure the apoplast solute potential (Psi(A)(s)) and assay the sap composition. The Psi(A)(s) was about -0.2 MPa early in development, decreased about 1.0 MPa by veraison, and continued to decrease during ripening to almost -4.0 MPa by the end of berry development. Potassium, malate, tartrate, proline, glucose, fructose, and sucrose were quantified in apoplastic sap. The calculated contribution of these solutes was about 50% of the total Psi(A)(s) preveraison, but increased to about 75% as fructose and glucose accumulated during ripening. The contribution of the estimated matric potential to apoplast water potential decreased during development and was only 1.5% postveraison. We conclude that high concentrations of solutes accumulated in the mesocarp apoplast prior to veraison, and that P loss was a direct result of decreased Psi(A)(s). Because Psi(A)(s) decreased before veraison, our findings suggest that apoplast solutes play an important role in the events of cellular metabolism that lead to the onset of ripening.

DOI： 10.1007/s00425-008-0707-3

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：AMER SOC HORTICULTURAL SCIENCE  

Two cultivars of tulip (Tulipa gesneriana L.) were used to check the effect of trehalose-feeding on longevity of vase life. 'Oxford' plants were grown from bulbs, and trehalose-fed cut flowers were compared with the intact plants grown in pots. 'Pink Diamond' flowers were obtained commercially as cut flowers from the market, and trehalose-feeding was examined by using only flower parts. In both cultivars of plants, it was confirmed that trehalose-feeding enhanced longevity of the vase life significantly at room temperature. Additionally, mechanisms of prolonging the vase life with trehalose-fed flowers were studied by comparing the water status in the zone of elongation of tulip tepals when their growth rates were modified with different treatments. In the elongating region of tulip tepals, cell elongation rates were linearly correlated to sizes of the growth-induced water potential regardless of treatments. It was found that trehalose-feeding reduced the hydraulic conductance, resulting in a decrease in cell elongation rates. Also, trehalose helped to maintain turgor of tepal cells for longer periods. Furthermore, trehalose enhanced pigmentation in tepals, and thus, trehalose is believed to have had a role in altering the metabolism in elongating cells and in reducing hydraulic conductivity in membranes.

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本生物環境調節研究会  

DOI： 10.2525/ecb1963.42.193

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本生物環境調節研究会  

DOI： 10.2525/ecb1963.42.205

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：低温生物工学会  

Role of trehalose on water status of cut bulbous flowers was determined by T_1 T_2 (^1H-NMR relaxation times) and with isopiestic psychrometers in relation to sugar accumulation and protein content at growth and senescence stages. Treatment with 100mM or 50mM trehalose markedly prolonged vase-life in gladiolus and tulip flowers, respectively. Trehalose maintained a higher degree of water content accompanying with supressing protein degradation in gladiolus petals than control tissues. Short T_2s estimated as bound water from cytoplasm and the apoplastic regions were determined by solid echo technique. Preserving the initial values in short T_2s at 3d after trehalose-treatment suggested that bound water in gladiolus petal tissues was maintained. On the other hand, long T_1 of the intracellular water in tulip tepal tissues showed that trehalose functioned to protect vacuolar water. Furthermore, trehalose affected to enhance water uptake into tepal tissues though not to promote cell elongation and not to cause osmotic adjustment with maintaining high level of turgor. From these results, it suggests that trehalose does not act as an energy source or directly participate in osmoregulation and these characteristics distinguish it from other sugars such as sucrose. In cut gladiolus and tulip flowers trehalose may play an important role to prevent loss of water determined by T_1, T_2 and turgor with protecting macromolecules.

DOI： 10.20585/cryobolcryotechnol.46.2_108

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記述言語：日本語  

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記述言語：英語   掲載種別：記事・総説・解説・論説等（国際会議プロシーディングズ）  

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記述言語：日本語   出版者・発行元：養賢堂  

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記述言語：日本語   出版者・発行元：日本作物学会  

DOI： 10.14829/jcsproc.233.0.190.0

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DOI： 10.14829/jcsproc.233.0.426.0

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記述言語：日本語   出版者・発行元：日本作物学会  

DOI： 10.14829/jcsproc.230.0.144.0

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記述言語：日本語  

DOI： 10.14829/jcsproc.229.0.300.0

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DOI： 10.14829/jcsproc.227.0.36.0

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：ELSEVIER SCIENCE INC  

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（国際会議）   出版者・発行元：OXFORD UNIV PRESS  

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記述言語：英語   出版者・発行元：Japanese Society of Plant Physiologists  

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その他リンク： https://projects.repo.nii.ac.jp/?action=repository_uri&item_id=184992

記述言語：日本語   出版者・発行元：日本作物学会  

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記述言語：日本語   出版者・発行元：日本作物学会  

インゲンマメ種子において, 水ストレス負荷による活性量の低下から, キトビアーゼは水ストレスに感受性を持つ可能性が示唆された。

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記述言語：日本語   出版者・発行元：日本作物学会  

水ストレス下でのインゲンマメにおいて, 葉の水分状態, 光合成および転流の関係について検討した。

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記述言語：日本語   出版者・発行元：日本作物学会  

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記述言語：日本語   出版者・発行元：日本作物学会  

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記述言語：日本語   会議種別：シンポジウム・ワークショップ パネル（指名）  

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記述言語：英語   会議種別：口頭発表（招待・特別）  

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記述言語：英語   会議種別：口頭発表（一般）  

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記述言語：英語   会議種別：口頭発表（一般）  

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https://orcid.org/0000-0003-0510-5744

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