Effects Of Uniconazole Applied To Seed On Seedling Growth And Yield Of Soybean Under Different Water Stress

The effects of uniconazole applied to seed with different concentrations (0,0.05, 0.1,0.2 and 0.4mg/kg) , which was under different water stress (normal irrigation, slight water stress and middle water stress),on morphological and physiological effect of seedling and yield were studied by using soybean variety-Zhe chun 3 in seedling. The effects of uniconazole on the drought resistance of soybean were evaluated by using the weighed average of comprehensive subordinate function values. The principal results were as follows:1. The uniconazole treatments cultivated strong seedling. After uniconazole treatments, the plant height was significantly lowered and stem diameter was significantly enhanced; the accumulation of total dry substances of on-ground part were increased; Uniconazole improved the assignment of dried substances in different organs, promoted the export of dried substances in leaves and root, enhanced the ratio of leaves and root, increased root-shoot ratio and leaf area.2. The uniconazole could significantly improve the content of ABA. Under water stress, not only ABA largely accumulated in soybean, but also the uniconazole treatments prolonged the time reaching to the maximum ABA accumulation. After 26-day of seeding, under slight water stress, the content was the best with the concentration of 0.2mg/kg; under middle water stress, the content was the best with the concentration of 0.4mg/kg.3. The content of MDA was treated by uniconazole that was lower than check, furthermore, the concentration of uniconazole was higher, the content of MDA was lower. Under slight water stress, the activity of SOD , POD and CAT was the best with the concentration of 0.2mg/kg; compared with check ,they increased by 21.9%, 12.6%and 46.4% respectively. Under middle water stress, the activity of SOD,POD and CAT was the best with the concentration of 0.4mg/kg, furthermore ,compared with check, they increased by 26.1 %,18.7% and 43.3 % respectively.4. The content of soluble sugar ,proline, soluble protein,relative water, chlorophyll and root activity which were treated by uniconazole were higher than check. Under slight water stress, the content of soluble sugar ,proline, soluble protein , chlorophyll and root activity which were treated by concentration 0.2mg/kg were the best, and compared with check, they increased by 21.2%, 21.2%, 22.5%, 9.7% and 36.7% respectively. Under middle water stress, the content of proline, soluble protein, relative water, chlorophyll and root activity which were treated by concentration 0.4mg/kg were the best, moreover, compared with check, they increased by 17%, 47.6%, 6%,10.4%and 56.3%...