Induced Resistance Of Pumpkin To Thrips Palmi

In this paper,host plants(Jintai No.1 and Jinxiang pumpkin,two pumpkin varieties),which were the most common,favorite and economically valuable crops,were treated with five exogenous inducers(Methyl Jasmonate(MeJA),Salicylic(SA),human induced(R),Thrips palmi induced(C),normal growth(CK)).The inductional time was 12 h,24 h,48 h,72 h,120 h,12 h,24 h,48 h,72 h,120 h.The nutrient contents(soluble sugar,protein,amino acid,flavonoids,crude fat)and enzyme activity(PPO,POD,CAT,SOD)were measured.The volatile constituents and the behavioral response of T.palrmi were analyzed.Thereby exploring or analyzing the insect resistance mechanism of pumpkin to T.palmi,and providing a theoretical basis for the prevention and control of the pumpkin crop in T.palmi.The main results obtained are as follows:1?Comparison of the number of T.palmi on the plants of the two pumpkin varieties:T.palmi prefers to eat young leaves,and Jintai No.1 is more vulnerable to T.palmi than Jinxiang pumpkin,and there is a significant difference.2?Amino acids and PPO,POD,SOD can be used as identification indexes of pumpkin resistance to T.palmi,The correlation between physiological indexes of pumpkin plants and the degree of resistance to T.palmi is as follows:SOD>amino acid>POD>CAT?flavonoids>reducing sugar>PPO= protein>lipids.3?Four inducing factors that MeJA,SA,R and C can increase the contents of reducing sugar,amino acids and flavonoids in host plants,and accelerate the enzyme activities of PPO and POD as well.Among them,the contents of amino acids,flavonoids(except SA)and the activities of PPO and POD(except MeJA)increase with the extension of induction time.MeJA can not induce the increase of protein content and CAT enzyme activity in pumpkin.C has not significant effect on lipid content and SA on SOD enzyme activity.Both CAT and SOD enzymes are significantly correlated with induction time,but not regularly.4?The four induction methods can increase the volatile matter of pumpkin leaves.The volatiles induced by T.palmi are the most,while the normal growth is the least.The volatile substances of alkanes,terpenes and aromatic hydrocarbons are the most in pumpkin.The phobotaxis of induced hosts to T.palmi is C>MeJA>SA>R>CK,from large to small.The avoidance of seven standards for T.palmi from large to small is octane>4-methyl-heptane>camphor>basil>3-methyl-heptane>1-ethyl-4-methylbenzene>3-carene.