Studies On Ultradry Storage And Mechanisms Of Desiccation Tolerance Of Rice Seeds

The previous studies suggested that seed ultradry in favor of conservation of germplasm resources. Preservation characters of ultradried seed have a quite difference between different species and varieties. We collected three rice varieties that make it to material to carry through the comparative studies of ultradry preservation characters and educed orders tolerance of desiccation in three rice varieties, as analysed different reasons of desiccation tolerance from some point of views, and according to the difference of desiccation tolerance explored its mechanism.1. The results of ultradried and aged rice seed viability and vigor showed Indica rice C38 germination percent fall range was less but Japonica riceJing21 and hybrid rice Qiuyou3 was great. In the grades of moisture content we were treated seeds that optimum moisture content between 4% and 6% at 50℃ was aged. The difference is that moisture content 6% of Japonica riceJing21 and hybrid riceQiuyou3 have better effects of preservation, but Indica rice C38 at 4%. The up result that Indica rice C38 have better tolerance desiccation.2. The study of water state in seed after ultradied that we first used temperature gravity instrument (TG) to accurately tested to total moisture in seed accorded with data of dried seed, then utilized to differential scanning calorimetry(DSC) e to tested proportion of bind/free water and conversive temperature of vitrification(Tg), gained to research result Tg of Indica rice C38 more than Japonica riceJing21 and hybrid riceQiuyou3, that proportion of bind/free water Indica rice C38 more than Japonica riceJing21 and hybrid riceQiuyou3, and proportion of bind/free water according with tolerance desiccation is positive., The results showed that xiandaoC38 have more strong ability of tolerance desiccation.3. Analysis of soluble sugars content and composition in ultradied seed showed that reduce seed moisture content with sucrose content was heighten as well as amylase and glucose content were fell. And sucrose content of Indica rice C38 obviously less than Japonica riceJing21 and hybrid riceQiuyou3, which have consanguineous relativity with difference of seed tolerance desiccation.4. Studies on the results of anti-oxidase system of ultradried seed showed that ultradried treatment can enhance tolerance desiccation of rice seed, but ultradried preservation exists to optimum moisture content. As anti-oxidase system were better maintained and Indica rice C38 less than two in the ultradied seed. When seed germinating, the enzymes fast expressed activities for cleaned injurant such as active oxygen and free radical in seed for prevent to injury of oxidate and pre-oxidate, which the sake of seed can normally germinate.