Effects of Salicylic Acid and Leaf Cutting Amount on Activities of the Primary Defense Proteins in Needles of Larix kaempferi
In order to clarify the effect of salicylic acid (SA) and leaf cutting amount on the induced insect resistance of Larix kaempferi, the whole plant was sprayed with different concentrations of SA and different degrees of leaf cutting treatment, and the activities of several main defense proteins in the needle were analyzed. The results showed that the activity of main defense proteins in needles was significantly affected by different concentrations of SA. Exogenous spray applications of 0.1mmol∙L-1 SA had significant effect on PAL activity in Larix kaempferi needles, and the change of PPO, POD activity was significant in 0.01 mmol∙L-1. Within 1-7 days after leaf cutting, the protease activity in needles changed significantly. The 25% leaf cutting treatment had the best induction effect on POD activity and the induction effect of PAL, CAT and PPO activity was significant in 50% leaf cutting treatment. Thus it can be seen that SA and leaf cutting can affect the activity of several main defense proteins in Larix kaempferi needles and improve their insect resistance.