EFFECTS OF AM FUNGUS INOCULATION ON PHYSIOLOGICAL AND PHOTOSYNTHETIC CHARACTERISTICS OF CARAGANA LEAVES UNDER SOIL COMPACTION STRESS

The effect of AM fungus inoculation on physiological, biochemical and photosynthetic characteristics of caragana leaves under soil compaction stress was studied. The results showed that the soil compaction led to the antioxidant enzymes activity of SOD, POD, CAT decreased, the content of proline, soluble sugar and soluble protein decreased, and the relative electrical conductivity and malondialdehyde increased significantly. Inoculation of AM fungus could improve the physiological characteristics of caragana leaves and enhance photosynthesis. Under soil compaction stress, the activity of antioxidant enzyme SOD, POD and CAT in caragana increased by 1.34, 1.65, 1.51 after AMF inoculation. The content of soluble sugar and soluble protein increased by 33.90% and 5.30% respectively, and the content of proline decreased by 53.20%. The relative conductivity and malondialdehyde content of the leaves decreased significantly by 15.58% and 19.98%. The secretion of hormone regulating substances IAA, CTK and GA increased by 18.39%, 45.19% and 14.40%, and ABA decreased by 34.33% with the inoculation of AMF. The net photosynthetic rate, stomatal conductance and transpiration rate of leaves were significantly increased. The results showed that the inoculation of AMF could improve antioxidant enzyme activity, regulate osmotic substance and hormone secretion, reduce lipid peroxidation level of cell membrane, maintain cell structure stability, promote photosynthesis and increase productivity. In the mining area with serious soil compaction, the inoculation of AMF could improve the ability of caragana to resist compaction stress, and improve the quality of vegetation restoration in mining areas.