Influence Of Soil Drought On Seeds Germination And Seedling Growth Of Soybean And Compensatory Effects Of Rewatering During Middle-late Growth Stage

Soybean is a kind of crops that needs large quantity of water and is sensitive to water stress during growth season. Aimed at the damage caused by seasonal drought in soybean production regions in southwest of China, the study was conducted, through a experiment simulating drought stress by PEG, and two pot experiments by manual rigorously controlling soil potential, to indentify drought resistance of eleven mid-season and summer soybean varieties at germination stage, and to study the responses of soybeans with different drought resisiance to soil drought during germination and seedling stage respectively and the compensatory effects of supplying water after drought during middle-late growth stage. The main results showed that:1. Eleven varieties were divided into drought resistant, moderate drought resistant and drought sensitive three groups by means of cluster analysis. Correlation analysis showed that, germinability, germination percentage, germination index, transformation percentage of stored substance and dry weight of root was suitable parameter for evaluating drought resistance.2. The stored substances in seeds of two soybean cultivars with high drought resistance were affected by soil drought stress during germination stage. That the decomposition and transportation of stored substances in cytoledons were affected significantly by moderate and severe drought stress might be the main reason of that drought prolonged emergence and inhibited the growth of radicle. The adaptability of Dongxuan1 under drought stress was stronger than Gongxuan 1.3. The longitudinal growth and cross growth of the shoot of plant were inhibited , and for three cultivars with different drought resistance, the morphological indexes, such as plant height, stem diameter, node number, branch number, green leaf number, of plant was A3(moderate drought)