ABSTRACT
Objective To study the physiological characteristics of Codonopsis Radix under drought stress; To reveal the physiological mechanism of Codonopsis Radix in response to drought stress. Methods Method of pot experiment was used to set up 4 water treatments: normal water supply, mild stress, moderate stress and severe stress. Through the determination of leaf relative water content, cell membrane permeability, osmotic adjustment contents and protective enzyme activity, the effects of drought stress on physiological characteristics of Codonopsis Radix were studied. Results With the drought stress increased, the chlorophyll a, total chlorophyll content and leaf relative water content of Codonopsis Radix decreased, but chlorophyll b had no obvious change; The conductivity increased first and then decreased; MDA contents increased first and then decreased and then increased; There was no significant change in the rate of superoxide anion production; POD and CAT activity increased; SOD had no significant change; The proline content increased first and then decreased; soluble sugar decreased; soluble protein had no significant change. Conclusion Under the condition of drought stress, by increasing the content of proline to regulate cell osmotic potential, Codonopsis Radixcan increase the antioxidant enzyme activity to reduce membrane lipid peroxidation damage to cells.