The Impact Of Drought Stress And Rehydration On Antioxidant Properties Of Soybean

A two-year pot experiment(from 2015 to 2016)with Heinong44 and Heinong65 was conducted at Northeast Agricultural University.This experiment adopts the weighing method combined with soil moisture measuring instrument to control moisture content,At the beginning of flowering stage,the natural drought treatment was carried out,and the drought stress treatments were maintained at different levels.We studied the effects of osmotic adjustment substances,antioxidant capacity,antioxidant enzymes and Isozymes on drought stress,as well as the rewater compensa tion effect.The main conclusions were as follows:(1)Drought stress increased the content of osmotic adjustment substances in leaves,with the aggravation of drought stress and the extension of stress time,the proline content increased continuously,The content of soluble sugar and soluble protein show a decreasing trend,After rewatering,all physiological indexes have compensatory effect,the compensation effect was the most obvious after moderate stress rewatering.(2)The capacity of total antioxidant increased in leaves under drought stress.Throughout the treatment period,but in addition to HN65 continued severe drought 4-5 days,the total antioxidant capacity was higher than that of control,during the treatment period,the superoxide anion scavenging capacity and hydroxyl radical scavenging capacity show increased first and then decreased.The total antioxidant capacity,superoxide anion scavenging capacity and hydroxyl radical scavenging ability of HN44 were higher than that of HN65.After rewatering,antioxidant capacity had occurred compensation effect,With the increase of the degree of drought,the compensation effect is weakened.(3)The activity of antioxidant system increased in leaves under drought stress.With the increase of the degree of drought and the extension of stress time,antioxidant enzyme activity decreased,SOD,CAT and GR peak appeared earlier than POD,APX,This indicated that the effects of SOD and CAT were higher than those of POD and APX under drought stress.During drought stress treatment,with the increase of the degree of drought and the extension of stress time,the content of MDA increased gradually,the content of MDA in HN44 was lower than that of sensitive HN65.This indicated that the HN44 plasma membrane was damaged to a lesser extent.After rewatering,antioxidant activity and MDA content were gradually restored,antioxidant enzyme activity had occurred compensation effect,With the increase of the degree of drought,the compensation effect is weakened,the compensation effect was the most obvious after mildly stress rewatering.(4)Drought stress caused the change of the main antioxidase isozyme zymogram,with the aggravation of drought stress,SOD,POD isozyme bands reduced and express quantity reduced;in addition,CAT bands remain unchanged and express quantity reduced.