Effects Of Exogenous Nitric Oxide On Physiological Characteristics Of Drought Resistance Of Soybean Under Drought Stress

Soybean is one of the most important food and oil crops in China.Drought is one of the most important abiotic factors that restrict the growth and yield of soybean.Nitric oxide plays an important role in signal transduction and regulation of plant physiological characteristics under stress.In order to explore the effect of exogenous nitric oxide on the physiological regulation of Soybean under drought stress,and to open up new ideas for the study of drought resistance of soybean,the experiment was designed and carried out.In 2018-2019,the effects of different levels of exogenous monooxygenation(SNP as donor)on the physiological characteristics of drought resistance of soybean were studied by pot planting in the glass rain proof shed of Northeast Agricultural University.The drought resistant cultivar Heinong 44(HN44)and the sensitive cultivar Heinong 65(hn65)were used as the experimental materials under drought stress during the flowering period.The main conclusions are as follows:(1)The content of no in soybean leaves increased under drought stress,and the content of HN44 was higher than that of hn65.Under the treatment of exogenous SNP,the content of no in soybean leaves continued to rise,reaching the maximum value when SNP reached 1000.00 ? mol / L and 7 days after treatment.The growth rate of no content in sensitive hn65 was higher than that in drought tolerant HN44.(2)The activities of nitrate reductase and nitrite reductase in the leaves of soybean decreased under drought stress.The activities of nitrate reductase and nitrite reductase in the drought tolerant cultivar HN44 were higher than those in the sensitive cultivar.Under the treatment of exogenous SNP,the activities of nitrate reductase and nitrite reductase in soybean leaves continued to decline,and the SNP reached 1000.00 ? mol / L and reached the minimum value after 7 days.The decrease rate of nitrate reductase and nitrite reductase activity of sensitive hn65 was higher than that of drought resistant HN44..(3)Drought stress increased the activities of antioxidant enzymes in soybean leaves.The activities of antioxidant enzymes in the drought tolerant variety HN44 were higher than those in the sensitive variety.Under the treatment of exogenous SNP,the activity of antioxidant enzymes in soybean leaves continued to rise,reaching the maximum value when SNP reached 1000.00 ? mol / L and 7 days after treatment.The growth rate of antioxidant enzyme activity of sensitive hn65 was higher than that of drought resistant HN44.(4)The content of osmoregulation substance in soybean leaves increased under drought stress.The content of osmoregulation substance in drought tolerant variety HN44 was higher than that in sensitive variety hn65.Under the treatment of exogenous SNP,the content of osmoregulation substance in soybean continued to increase,reaching the maximum value when SNP reached 1000.00 ? mol / L and 7 days after treatment.There was no significant difference between sensitive type hn65 and drought resistant type HN44.(5)Drought stress increased the membrane lipid peroxidation of soybean leaves,and the membrane lipid peroxidation of drought tolerant cultivar HN44 was less than that of sensitive cultivar hn65.Under exogenous SNP treatment,malondialdehyde content in soybean leaves continued to decrease,and the minimum value was reached when SNP reached 1000.00 ? mol / L and treated for 7 days.There was no significant difference in the reduction rate of malondialdehyde between sensitive type hn65 and drought resistant type HN44.(6)Drought stress increased the content of abscisic acid and free salicylic acid in soybean leaves,and the content of abscisic acid and free salicylic acid in drought tolerant cultivar HN44 was higher than that in sensitive cultivar hn65.The content of abscisic acid and free salicylic acid in soybean leaves increased continuously when SNP reached 1000.00 ? mol / L and reached the maximum value when treated for 7 days.The increase rate of abscisic acid and free salicylic acid in sensitive type hn65 was significantly higher than that in drought resistant type HN44.