Morpho-Physiological Response of Oryza glaberrima to Gradual Soil Drying

Soil drought occurrence during dry season has been the main constraint, besides prolonged flooding during rainy season, in increasing cropping intensity and rice productivity in tropical riparian wetland. Use of drought tolerant rice genotype might be a suitable option for overcoming such problem. This study focused on the effects of gradual soil drying during early vegetative growth stage on morphological and physiological traits of five Oryza glaberrima genotypes, namely RAM12, RAM14, RAM59, RAM97 and RAM101, and two Oryza sativa subsp japonica genotypes, i.e. Koshihikari and Minamihatamochi. The plants were subjected to 6 d of gradual soil drying condition from 15 days after transplanting (DAT) to 20 DAT, and were allowed to recover until 22 DAT. Gradual soil drying reduced plant growth as indicated by dry mass accumulation. Drought reduced stomatal conductance and increased leaf rolling score of all the genotypes. All the genotypes showed comparable response on stomatal conductance, but O. glaberrima genotypes performed higher in leaf rolling recovery. Meanwhile, O. sativa genotypes decreased total leaf area and specific leaf area, but increased specific leaf weight in order to avoid further damages due to drought stress. Drought tolerance mechanisms in RAM101, RAM12, RAM59 and RAM14 were associated with leaf morpho-physiological responses, root traits and dry biomass accumulation.     

新疆野生沙枣仁中脂肪和蛋白质组分的研究

[目的]研究新疆野生沙枣仁中脂肪和蛋白质组分。[方法]采用气质联用法测定新疆野生沙枣仁油脂中脂肪酸的含量及组分;采用分级提取法分离沙枣仁中的蛋白质,并用半微量定氮法对蛋白质中的氨基酸组分进行分析。[结果]新疆野生沙枣仁的含油率为8．2％．以不饱和脂肪酸为主要成分,其中以亚油酸含量最高,为46．52％,其次为油酸,亚麻酸和硬脂酸。沙枣仁中粗蛋白平均含量为11．31％。其中以球蛋白和清蛋白为主,占蛋白质总量的70％以上,而残渣蛋白、醇溶蛋白、谷蛋白含量比较低。沙枣仁蛋白质中含有18种氨基酸,其中天冬氨酸含量最高,为12．7％,其次为谷氨酸,占11．8％,酪氨酸为9．33％,亮氨酸为8．11％,赖氨酸为7．22％,精氨酸、丝氨酸、丙氨酸、缬氨酸含量次之,组氮酸、蛋氨酸和胱氨酸含量最少。其中人体必需氨基酸含量达28．76％。[结论]新疆野生沙枣仁营养丰富,具有广阔的应用前景。