Study On Drought Resistance And Screening Of Drought Resistance Identification Indexes In Rice Varieties During Seedling Stages

95 rice varieties were provided by Rice Research Institute of Sichuan Agricultural University and its collaborated unit. The morphological, growth and development indexes of drought resistance were tested and analyzed during bud and seedling stages. Using the relative magnitudes of representative varieties which had different drought resistances, the morphological changes of plants, physiological functions and biochemistry characteristics, and their relations with drought resistance were studied. Based on the grey system theory and through grey correlation analysis and principal components analysis, a set of convenient and reliable identification index system of drought resistance during seedling stage were established. The following four sections concluded the core points of this study.1. Plant growth was inhibited under water stress. During bud stage, germinative force and germinative rate were inhibited, and the bud length, coleoptile length, root number, embryonic-root length, and dry matter were decreased accordingly compared with controls. Germinative rate was an important index for identification of drought resistance in bud stage, and it was significantly correlated with germinative rate, germinative force, root length, bud length and bud dry weight. As a result, these four indexes could be used as the indexes for identification of drought resistance. In addition, the plant height decreased under drought stress condition at seedling stage, and the leaf age, leaf growth, and dry matter accumulation had been restrained to some degree. Through path analysis, drought resistance was closely related to leaf age, lengths of the first leaf and the second leaf from the top, and areas of the second leaf from the top.2. There were conspicuous changes on physiological metabolism in plants under water stress. The soluble sugar, soluble protein, amino acid content, MDA, Vc, and GSH content increased, while RWC, leaf water potential, Pro content decreased; the activities of antioxidation conservative enzyme such as SOD, POD, CAT increased, while activity of NR, nitrate-nitrogen content and ABA content increased. According to correlation analysis, drought resistance was closely related to leaf water potential, RWC, amino acid, MDA, Vc, GSH content and SOD activity. Among indexes tested in this study, there was...