Response Mechanism Of Seedlings Of Ammopiptanthus Mongolicus To Drought And High Temperature Stress

In this study,Ammopiptauthus.mongolicus?Maxim?.Cheng f.was used as the research object to understand the tolerance of seed and seedlings of Ammopiptanthus mongolicus to drought and high temperature stress,and to understand the plants in arid and semi-arid regions in adversity.Ecological countermeasures and response mechanisms are designed to provide a theoretical basis and application guidance for protecting endangered plants and improving species tolerance.The findings are as follows:1.Within a certain range,as the water temperature continues to rise,the germination rate of Ammopiptanthus seeds also increases.At 60⁸0°C,the seed germinating effect is best and the hard seed has stronger resistance.5%PEG solution can effectively improve the activity index of Ammopiptanthus mongolicus seed.2.Under different levels of drought stress,the biomass,leaf specific gravity,stem specific gravity and relative water content of Ammopiptanthus mongolicus seedlings decreased to varying degrees,but the MDA content of seedling leaves first decreased and then increased,SOD activity.,CAT activity and Pro content increased first and then decreased.The indicators of seedlings reached the peak on the 8th day.3.With the prolongation of drought time,the contents of photosynthetic pigments Chla,Chlb,?Chla+Chlb?and carotenoids in the leaves of Ammopiptanthus mongolicus seedlings were all increased first and then decreased,and they reached the peak at the 8th day.However,the intercellular CO₂ concentration,stomatal conductance,net photosynthetic rate and transpiration rate of seedling leaves gradually decreased.4.Under high temperature stress,the cell injury rate of the leaves of Ammopiptanthus mongolicus seedlings showed an“S”pattern with increasing temperature,and the semilethal high temperature?LT50?of the seedlings was between 52.55 and 55.42°C.According to the analysis of the changes in the indicators of adversity in Adversity,Ammopiptanthus mongolicus seedlings have some resistance and adaptability to drought and high temperature stress,and can increase their stress resistance by regulating the mechanism of seedlings in vivo.