Effects On Physiological And Biochemical Characteristics Of Cerasus Sachalinensis Roots Under Combined Stress

Cerasus sachalinensis is widely cultivated as a sweet cherry rootstock in Dalian,Liaoning Province,because of its advantages of cold resistance and high propagation rate.Because of its shallow roots,it is a typical waterlogged plant,so its development is greatly limited.However,acturally,waterlogging and other stresses can cause plant death during production,such as soil salinization or high temperatures caused by sunny days after heavy rain in summer.In order to investigate the damage mechanism of waterlogging and other environmental stress on cherries,this study simulates waterlogged environment,high temperature environment,soil salinization,high temperature and waterlogged superimposed environment,salinity and waterlogging interaction,and understands the effects on the respiratory metabolism and reactive oxygen metabolism pathways of the roots of Cerasus sachalinensis.The main results are as follows:1 The root function of Cerasus sachalinensis was affected under high temperature stress and waterlogging stress.The activity and total respiration rate of roots showed a decreasing trend during the whole treatment.However,the respiratory rate of EMP pathway increased in the early stage of stress and then was inhibited,while the respiratory rate of TCA and PPP pathway was inhibited from the beginning of treatment.At the same time,the content of non-structural carbohydrates decreased,and the pyruvate content showed a trend of increasing first and then decreasing,reaching a peak at 24 h.The combined stress of high temperature and waterlogging aggravated the damage of the root system function,and the total respiration rate of the root system decreased significantly compared with the single stress,and the TCA and PPP pathways are reduced by 25.71% and 20.21% respectively compared to waterlogging.The pyruvate content accumulated rapidly,and the maximum value appeared at 12 h,which was 30.74% lower than that of the waterlogging treatment.2 The reactive oxygen metabolism was affected under the single stress.The content of O2.-,H2O2 and MDA in the roots of Cerasus sachalinensis increased significantly during the treatment.The content of non-enzymatic antioxidants in root system increased in the early stage of treatment;the activity of antioxidant enzymes CAT、POD and APX were significantly increased.Under the combined treatment waterlogging and high temperature,the activity of CAT peaked at 24 h,increasing by 105.55% and 207.56% respectively,but under salt treatment,the activity of CAT reached its maximum value at 3 d.Under the combined stress of waterlogging and high temperature,the contents of As A,DHA,GSSG,and GSH all showed a trend of rising and then falling,As A and GSH contents reached the maximum value at 12 h,DHA content reached the peak value at 6 h and GSSG content reached the peak value at 48 h.3 Compared with waterlogging stress,high temperature stress and salty stress,the combined stress further intensified the production of reactive oxygen species,the content of MDA in the root system increased,and increased the degree of membrane lipid peroxidation and antioxidant enzyme activity significantly increased,as the stress time prolonged,the antioxidant enzyme system was destroyed.