Cotton Defense Response Induced By Spider Mite And Physiological Responses Stressed By Acetamiprid

Take T.urticae- cotton as research system, the defense enzymes,defense key genes and its expression,nutrients, secondary metabolism index and key enzyme activity changes were studied on the level of physiological and biochemical and molecular level by theresistance mechanism induced by T.urticae feeding plant. The aim is to clear the defense mechanism induced by T.urticae and explain the interaction mechanism between plants and pests. The main conclusions are as follows:(1) Effect of Chlorophyll,secondary metabolites and nutrients induced by T.urticae Cotton chlorophyll content induced by T.urticae showed decline trend with the increase of the feeding time and the number of T.urticae, but it was opposite induced by aphis gossypii and T.urticae. This may be caused by the aphis gossypii and T.urticae competition. Soluble protein and soluble sugar showed a trend of rising with the increase of the feeding time and the number of T.urticae., but the polyphenols showed a opposite trend.(2) The effects of T.urticae damageing on defense enzyme activity The activity of CAT、POD、PPO and LOX from cotton leaves fed by T.urtica presented different chang on different varieties. The leaves of four defense enzyme activity in ZHong Mian Suo49, Xinluzhong 37 were higher than ZHong Mian Suo 35, and the activity of CAT、PPO and LOX in cotton leaves show a trend of decline after rising with the extension of the induction time, the activity of POD and PAL in cotton leaves show a trend of rising with the increase of the feeding time and the number of T.urtica. Cotton Leaves stress defense activity increased with the increase of the feeding time and the number of T.urtica,which show that the harm T.urticae can induce host plants produce a series of biochemical reactions, and different enzyme activities present different chang.(3) Effects of T.urticae feeding on cotton expression of Defense Gene With the increase of the number of T.urticae and the damage time, the relative expression of defense key genes(pal, cat, pod, ppo) hd taken place different changes in cotton leaves. The relative expression of cat gene showed a trend of decline after rising, and higher than contrast. The relative expression of pal gene showed a trend of decline after rising with the increase of the feeding time and the number of T.urtica. The relative expression of ppo gene gene was up- down- up trend. The relative expression of four defense enzyme gene was close to the change of defense enzyme activity and had an obvious difference, which the four kinds of defense genes may be multi-family gene regulation by multiple genes.(4) Effect of insecticides on detoxification enzymes and protective enzyme activities from T.urticae After dealing with water or acetamiprid on cotton leaves by fed T.urticae, which three protective enzymes(CAT, POD, SOD) and three detoxification enzymes(Ach E, Car E, GSTs)activity had changed.With the extension of feeding time, the enzyme activity declined. especially the activity of enzymes in T.urticae after dealing with acetamiprid than water treatment. This may be due to the need to produce immune after response of free radical scavenging, which reaction function of the related enzymes in T.urticae body was inhibited after dealing with acetamiprid, thus its ability to resist defense began to weaken, and show a overall trend of decline.