Study On Effect Of Exogenous Abscisic Acid On Nitrogen Accumulation Of Soybean Under Drought Stress During The Seed-filling Period

This experiment was conducted from 2015 to 2016 in Heilongjiang Bayi Agriculture University for grains with Suinong 26(drought-sensitive variety)and Kang xianchong 9(drought-resistant variety)by using 15 N labeling method and PEG were employed to silumated drought stress,to study the effect of exogenous ABA on nitrogen accumulation of soybean.The results showed that:The activities of key enzymes in nitrogen assimilation and transfer were significantly decreased by drought stress in two soybean cultivars during the seed-filling period.Exogenous ABA could alleviate this inhibitory effect of drought stress,especially it can significantly increased NR?GS?GOGAT and GDH activities in Suinong 26 during the early and middle of seed-filling period(drum grain after 7 d-14 d and 14 d-21 d).And it also significantly increased these enzyme activities in Kang xianchong 9 during the early of seed-filling period(drum grain after 0 d-7 d and 7 d-14 d).Exogenous ABA increased the leaf and root of GOT and GPT activity in two cultivars,the difference was not significant.Drought stress significantly decreased ureide content and increased the content of ammonium nitrogen and nitrate nitrogen in soybean plant for two cultivars during the seed-filling period.Exogenous ABA could decrease the content of ureide content,ammonia nitrogen and nitrate nitrogen in soybean plants caused by drought stress,and the effect was more pronounced in the early stage of the seed-filling period.Plant nitrogen accumulation were significantly reduced by drought stress in two soybean cultivars during the seed-filling period.Exogenous ABA could alleviate this inhibitory effect of drought stress on nitrogen accumulation(mainly mineral nitrogen)of soybean,and the mitigation effect was more pronounced in the early stage of the seed-filling period.Compared to drought stress,exogenous ABA increased fertilizer nitrogen accumulation in whole plant of Suinong 26 and Kang xianchong 9 during the drum grain after 0 d-7 d and 7 d-14 d,and respectively increased the rate of 4.20% and 3.89%,6.84% and 13.49%.Compared to drought stress,exogenous ABA increased nitrogen accumulation in whole plant of Suinong 26 and Kang xianchong 9 during the drum grain after 0 d-7 d and 7 d-14 d,and respectively increased the rate of 7.87% and 6.53%,5.57% and 4.24%.Drought stress significantly decreased the yield per plant of two soybean cultivars during the seed-filling period.Exogenous ABA could alleviate the yield loss caused by drought stress,and the mitigation effect was more pronounced in the early stage of the seed-filling period.Compared to drought stress,exogenous ABA increased yield per plant in two cultivars cultduring the drum grain after 0 d-7 d and 7 d-14 d,and respectively increased the rate of 22.08% and 24.87%,18.78% and 21.22%.