Physiological And Biochemical Mechanism Of Glycyrrhiza In Response To Drought Stress

In this paper,Glycyrrhiza uralensis seedlings as materials,Using pot water to simulate the method of drought stress,The external morphological and internal physiological and biochemical changes of glycyrrhiza seedlings under drought stress were observed,the main results were as follows:1.Under normal water supply,the leaves of glycyrrhiza are fresh and green,the branches are open,and the water content of the leaves is about 65.25%and stabilizes.With the duration of the drought,In mild drought stress(3d?6d),the external characteristics of licorice remain fresh and green and robust,and the water content of the leaves was about 55.97%;During moderate drought stress(9d?12d),some of the leaves were yellowed and wilted,and the leaves were about 37.35%.In severe drought stress(15d?18d),the plants are almost dry,most of the leaves are crimp and dry,and the leaves are only about 15.12%.2.Mild(3d?6d)under drought stress,glycyrrhiza almost all stomata open,at the same time,the leaf net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Gs)were higher than normal water supply,intercellular CO2 concentration(Ci)and chlorophyll content compared with no obvious change,RuBPcase activity increased slightly;Moderate(9d?12d)under drought stress,glycyrrhiza stomata closed gradually,leaf Pn continues to abate,Gs,Tr decreased gradually,Ci gradually rise,RuBPcase activity and chlorophyll content reduced;Severe drought stress(15d?18d),the pores of glycyrrhiza leaf were almost closed,photosynthesis was lost,and the activity of RuBP carboxylase and chlorophyll were decreased dramatically.3.Mild(3d?6d)and moderate(9d?12d)under drought stress,glycyrrhiza intracellular free proline content and soluble sugar content were increased by contrast,under severe drought stress(15d?18d),intracellular free proline and soluble sugar content decreased,But it's still higher than contrast.It is shown that the moderate drought stress glycyrrhiza can be used to prevent the loss of water and improve the ability of plants to resist drought.4.Mild(3d?6d)and moderate(9d?12d)under drought stress,glycyrrhiza leaf super oxygen anion free radicals and hydrogen peroxide content increased slightly by contrast,antioxidant enzyme activities of SOD and POD.MDA content increased slightly;And under severe drought stress(15d?18d),glycyrrhiza leaf Chinese super oxygen anion free radicals and hydrogen peroxide content increased significantly,SOD and POD activity showed a trend of decline,MDA content increased dramatically.Show that moderate drought stress glycyrrhiza can improve the activity of antioxidant enzymes ros accumulation,reduce the membrane lipid peroxidation damage,so as to improve plant drought resistance ability.5.With the increase of the degree of drought stress,the chlorophyll content gradually reduce,glycyrrhiza weakened photosynthesis,glycyrrhiza growth vigor drops,glycyrrhiza leaf of UWL value decline.The glycyrrhiza UWL value instead of photosynthesis and chlorophyll content of the leaf are closely linked.