The Effects Of Exogenous Sucrose On Tolerance In Potato Under Heat And Chilling

In recent years,with the global warming intensified,such as low temperature and high temperature and other extreme weather occurred more frequently.Abnormal changes in temperature seriously affect agricultural production and development.Potato is one of the four main staple foods in China.High temperature and low temperature stress are the main factors affecting the growth and development of potato.Sucrose represents the major transport form of photosynthetically assimilated carbohydrates and plays versatile roles in plants.On the other hand,sugars function directly as protective agents at higher concentrations,and they serve as substrates or signals for stress-induced alterations at low concentrations.In order to study the mitigation effect of sucrose on the low temperature and high temperature stress of potato,we used the potato seedling as the material for 1 day after pretreatment with exogenous sucrose for the low temperature and high temperature stress treatment respectively.The physiological and biochemical indexes were determined,and the sucrose was used to improve the low temperature and high temperature Tolerant mechanism.The main results are as follows:(1)After 11 hours of high temperature stress,the leaves of the control group and the sorbitol treatment group were wilted with distilled water,and the stalk was lodged with water,while the sucrose treated seedlings still did not appear to lose water.(2)After 4 hours-2? low temperature treatment,the sorbitol treatment group and the control group showed severe frostbite,the stalk was water-like,the leaf color was deepened,the sucrose treated seedlings still keep the leaves bright green,soft and flexible;(3)Pretreatment of sucrose with high temperature and low temperature could reduce the content of malondialdehyde and relative conductivity,and sucrose pretreatment reduced the damage of the membrane.(4)Sucrose pretreatment could reduce the content of hydrogen pe roxide in potato leaves at low temperature and low temperature,and decrease the generation rate of superoxide anion in potato leaves.The pretreatment of sucrose increased the activity of SOD in potato leaves at high temperature and low temperature,POD,CAT and APX enzymes,and alleviate the oxidative damag e caused by temperature stress.(5)Sucrose pretreatment increased sucrose content and total sugar content at high temperature and low temperature.Sucrose pretreatment could increase the contents of proline and soluble protein in leaves under high temperature stress.In summary,sucrose pretreatment of potato seedlings can reduce the levels of ROS and MDA in vivo,improve the activity of antioxidant enzymes and increase the contents of proline,soluble sugar and soluble protein,and improve the resistance to heat and chilling tolerance.