Effect of Soil pH on Activity of Protective Enzymes in Lupinus polyphylla Leaves

By using different levels of sulphur powder to adjust soil pH,determining the activity of superoxide dismutase(SOD),catalase(CAT),peroxidase(POD) and contents of malondialdehyde(MDA) in different growth periods of Lupinus polyphylla leaves,the effect of soil pH on activity of protective enzymes was studied to provide evidences for the cultivation of the plant.Different MDA contents were found in the leaves under different soil pH and different growth periods.The effect of soil pH on 2-year plants was greater than on the annual ones.The activities of POD decreased with the rising of pH value.Generally, there existed a rising trend for the effect of soil pH on the activity of POD in the leaves,indicating that the higher the soil pH,the lower POD activity in the leaves,and the lower soil pH can improve disease resistance, especially for the one-year plant.The activity of catalase was not significant different in different growth periods among under different soil pH.The activity of SOD decreased first and then increased along with the decrease of soil pH.The activity of SOD was higher in 2-year plants than in one-year ones.