A Study On The Mechanical Wounding Effects And The Defense Enzymes Response After Treating Cucumber Plants With Mechanical Wounding

In this experiment, the cucumber seedling were induced by mechanical wounding with different degrees at stage of cotyledon and the first true leaf, studying the visual damage effects on cucumber plant growth and the change of several key defensive enzymes activities in cucumber leaves, exploring the response to physiological and biochemical mechanism after mechanical wounding. then, these can provide a new understanding to mechanical injury signal transduction mechanism and provide important theoretical basis and practical value to cucumber disease induced resistance with mechanical wounding and the injury treatment in cucumber growth process, such as training, branch injury. The results showed that:1. Mechanical wounding with different degrees in cotyledon period and leaf period can inhibit the cucumber plant growth. After mechanical wounding treatment 15d at stage of cotyledon, the largest leaf area and leaf number with the control were reached a significant, very significant differences, after 20d, the width of cucumber plant with the control were reached a significant, very significant differences. After mechanical wounding treatment 15d at stage of the first true leaf, the height,the width,the largest leaf area and leaf number with the control were reached a significant, very significant differences.2. After mechanical wounding at stage of cotyledon or the first true leaf, chitinase,β-1,3-glucanase, PAL and SOD activities were higher than control. Cx andβ-glucosidase activities were lower than control in injury leaves, and defensive enzymes activity of all treatments peak appears between 36h and 168h after mechanical wounding at stage of cotyledon. After mechanical wounding 48h at stage of the first true leaf, Cx andβ-glucosidase activities were lower than control in injury leaves, and defensive enzyme activity of all treatments peak appears between 6h and 144h after mechanical wounding.3. Mechanical wounding at stage of cotyledon or the first true leaf can induced all kinds of defensive enzyme activities significantly in upper leaves. The activities of chitinase,β-1,3-glucanase, PAL and SOD in cucumber leaves were higher than that of the control after mechanical wounding. Cx andβ-glucosidase activities were lower in different degree than that of the control after mechanical wounding at stage of the first true leaf, and the activities of Cx andβ-glucosidase significantly lower than that of control in section 4,5 Leaf after mechanical wounding at stage of the cotyledon.It is concluded that mechanical wounding can lead to enzyme activities in the cucumber leaves significantly. Shows that mechanical wounding can effectively induce plant defense response, and make the appropriate response to repair damage, so that the induced resistance was produced strongly throughout the cucumber plants. After mechanical wounding, the production and accumulation of enzyme activity were also observed in the upper leaves , thus, the wounding signal transduction can be induced and the expression of injury induced gene can be activate by mechanical wounding in cucumber plant, so that defense enzymes can be produced in cucumber plant to resist external injury.