The Analysis Of Physiological Effect Of High Temperature And Strong Light On Kiwi Trees After Sustained

To study the influence of high temperature and strong light intensity after sustaining summer rainfall for kiwi trees on physiology and biochemistry in Shanghai,and explore the causes of the death of kiwi trees,my research will provide theoretical basis for figuring out the issues of the death of kiwi trees in Shanghai.My experiment adopted the method of artificial rainfall and simulative high temperature,strong light environment,using‘Xu Xiang’kiwi seedlings as the test materials.Soil water content under the treatment of different rainfall time with high temperature and strong light were conducted.The damage rate of each root and leaf net photosynthetic—Pn,Tr,Gs,Ci in kiwi seedlings were also measured.Then root samples were taken to laboratory to measure root activity and physiological indicators.With the prolonged duration of heavy rainfall,this experiment showed that the degree of damage to the kiwifruit leaves increased,and the degree of damage showed a significant positive correlation with the duration of high-temperature and strong light after strong rainfall.After3-5 days of strong rainfall,the kiwi trees leaf was exposed to high temperature and strong light for 3-4 days.Net photosynthetic rate（Pn）,transpiration rate（Tr）,stomatal conductance（Gs）decreased significantly,intercellular CO₂ concentration（Ci）increased,root activity decreased.The activity of the anti-oxidation enzymes SOD,POD,CAT and relative electrical conductivity,malondialdehyde（MDA）content,free enthalpy significantly increased.There is a nonlinear correlation between leaf damage rate and root vigor through the analysis of correlation.Strong rainfall for 3-5 days could lead to decreasing the root activity and increasing the membrane permeability.Beside,this treatment could cause the brown phenomenon of root and the decrease of absorption capacity.Then,under incubated in high temperature and strong light for 3-4 days,the plant could be death.The phenomenon may be related to the fact that the root system can not provide the moisture needed for transpiration at high temperature.