Studies On The Effects Of Heat-resistant Agent In Improving The Heat Tolerance Of Rhododendron Delavayi

Four factors on four levels of orthogonal design experiments were conducted to study theeffects of temperature and heat-resistant agent in improving the heat tolerance of four annualRhododendron delavayi. The main results are as follows:(1)The heat-tolerance of Rhododendron delavayi seedlings are low in natural state.Underthe stress of the different levels of high temperature(normal temperature、32℃、37℃、42℃),There were significant effects on Rhododendron delavayi. seedlings with the treatmentsof PAS、AA and CaCl2,which played a role in maintaining the seedlings’ normal physiologicalactivities under the stress of high temperature. According to the analysis of the correlation ofthe indexes,the content of MDA had positive correlation with the relative electricalconductivity;soluble protein, soluble carbohydrate and chlorophyll had positive correlationwith each other;the relative electrical conductivity had negative correlation with solubleprotein,soluble carbohydrate and chlorophyll.The physiological index of the seedlings startedto reach a significant level as the increment of stress. This indicates that the physiologicalindex were strengthen by each other and withstand the bad environment together.(2) Together with the observation of the plants’ real living condition,in the experiment ofexogenous heat-resistant agent, Membership Function was introduced to have a relativecomprehensive evaluation on heat-tolerance of Rhododendron delavayi under four levels offixed temperatures. Here are the results:normal temperature:PAS (100mg/L)+AA(200mg/L)+CaCl2(400mg/L) is the best compages to increase seedlings’ heattolerance.32℃: using the compages of PAS(200mg/L)+AA (600mg/L) can increase seedlings’heat tolerance observably.37℃: the compages of PAS (100mg/L)+AA (600mg/L)+CaCl2(800mg/L) can increase plants’heat tolerance observably.42℃: PAS (200mg/L)+AA(200mg/L)+CaCl2(1200mg/L) can increase plants’ heat tolerance observably.(3) Together with the observation of the plants’ real living condition,in the experiment ofexogenous heat-resistant agent, Direct Analysis of orthogonal design experiments wasintroduced to have a comprehensive and predictive evaluation on heat tolerance of seedlings. The results were as follows: normal temperature:PAS (100mg/L)+AA (200mg/L)+CaCl2(400mg/L) is the best compages to increase seedlings’ heat tolerance. This is similar to theanalysis of Membership Function.32℃: Using AA (600mg/L) alone or using PAS(300mg/L)+CaCl2(1200mg/L) together can increase plants’heat tolerance observably. This isdifferent from the analysis of Membership Function.37℃:the compages of PAS(300mg/L)+AA (400mg/L) or the compages of PAS (300mg/L)+AA (400mg/L)+CaCl2(1200mg/L) is the best compages to increase seedlings’ heat tolerance. This is similar to theanalysis of Membership Function.42℃: Using PAS (300mg/L)+CaCl2(1200mg/L) or PAS(300mg/L)+AA (400mg/L)+CaCl2(1200mg/L) can increase plants’heat tolerance observably.This is similar to the analysis of Membership Function.