Effects Of Arbuscular Mycorrhizal Fungus And Exogenous Salicylic Acid On Cold Tolerance Of Ziziphus Jujube ‘lizao’ Seedling Cultivated In Greenhouse

Lizao(Ziziphus jujuba‘Lizao’) not only have good taste and rich nutritional value, but also have extremely important function of edible, medicinal, ornamental, and construction. The effect of low temperature on growth is one of the important factors, it has become a serious problem to be solved in greenhouse Lizao production in early spring. In order to explore the synergistic effect of arbuscular mycorrhizal(AM) fungus and different concentration of salicylic acid(SA) on enhancing the cold tolerance of pants, we studied the effect of AMF Glomus mosseae and exogenous SA on cold resistance of potting Lizao seedling in greenhouse. Results showed that AM fungus inoculation and exogenous SA treatment can obviously improve the antioxidant enzyme activity of Lizao seedling leaves, increase the electric conductivity, and reduce the content of malondialdehyde under the sub-low temperature stress(Day temperature /Night temperature:15±0.5oC/10±0.5oC)and low temperature(Day temperature/Night temperature: 10±0.5oC/5±0.5oC). AMF inoculation and SA treatment simultaneously has the most significant effect, and the optimal concentration of SA is 600 mg/L-900 mg/L.1、 AMF inoculation and spraying 600 mg/L SA can increase water(low temperature: 13.48%; sub-low temperature: 6.50%)and chlorophyll(low temperature: 3.35%; sub-low temperature: 5.84%) content of leaf within a certain range, and it increase the photosynthetic rate and the accumulation of dry matter, improving plant height(low temperature: 15.42%; sub-low temperature: 9.66%) and stem diameter(low temperature: 4.74%; sub-low temperature: 4.55%) of Lizao seedling, enhancing the cold resistance;2、Membrane system is the most sensitive parts of the plant to chilling injury, AMF inoculation and spraying 600 mg/L SA can reduce the accumulation of intracellularMDA(low temperature: 5.63%; sub-low temperature: 17.31%), lighten the lipid peroxide level of leaf membrane under low temperature stress, to maintain the stability of cell membrane system;3、AMF inoculation and exogenous SA treatment can obviously improve the POD(low temperature: 35.71%; sub-low temperature: 53.85%), SOD(low temperature: 35.84%; sub-low temperature: 27.77%) and CAT(low temperature: 91.35%; sub-low temperature: 37.10%) enzyme activity of Lizao seedling leaves, which reduce the damage of superoxide, peroxide and hydrogen peroxide to cell and membrane system of Lizao seedling under low temperature stress;4、AMF inoculation and exogenous SA treatment increase the content of soluble sugar, soluble protein and Pro. Reducing freezing point and relative electric conductivity of organization(low temperature: 21.01%%; sub-low temperature: 18.30%), to maintain the stability of cell membrane, improving the protection ability of protoplasm and the cold tolerance of Lizao seedling under low temperature.This study proves that the AMF and SA adjusted the content and activity of some substances of Lizao seedling related to adversity, and the synergistic effect of AMF and SA on enhancing the cold tolerance of Lizao seedling. Provide theoretical help for improving the growth conditions of Lizao seedling in Changyi city,and it is able to guide the production of greenhouse Lizao in early spring.