Interaction Effect Between The Secondary Substances And Enzymes Of Cruciferae Vegetable And The Protective Enzymes Of Phyllotreta Striolata Under Pesticide Stress

The secondary substances content(glucosinolates,total phenols) and protective enzyme activity (POD,SOD,CAT) in Brassica campestris ssp.chinensis(L.) and the change of protective enzymes in striped flea beetle were determined after the vegetable was treated by three pesticides(carbosulfan, cyhalothrin EC and azadirachtin) in this paper.Electron microscope photoes of leaf treated by pesticide were also observed.The main results are as follows:Electron microscope observation showed that wax layer on leaf of Brassica campestris ssp. chinensis(L.) is unconspicuous on leaf epidermis,mainly distributing on Stoma,while cuticle can be found,appearing to be wrinkle or wavelike.Different degree of "dissolution" appeared in waxes on stoma of leaf treated by three pesticides 2 days after applying pesticide,it "dissolved" thoroughly 7 days after applying pesticide.but,gradually,wax recovered partially after 15 days.Compared with control,the area and thickness of "recovery" wax was reduced.It maybe concluded that wax "dissolution" caused by pesticide could make striped flea beetle to feed more easily,also lowered the insect resistance to striped flea beetle.Compared with control treatment,the glucosinolate content of leaf treated by three pesticides first lowered,then were higher than control treatment gradually after five days.The effect on glucosinolate content by pesticide were different among the three pesticides(carbosulfan,cyhalothrin EC,azadirachtin),the difference showed in rough:carbosulfan＞azadirachtin＞cyhalothrin EC.The content of total phenols in leaves treated by pesticide were lower than those of control treatment, which showed that the quality and insect resistance of Brassica campestris ssp.chinensis(L.) lowered by applying pesticide.Pesticide application could make cabbage attracting pest feeding more easily.The result of protective enzymes(SOD,POD,CAT) in leaves treated by three pesticides showed: activity of SOD treated by three pesticide were higher than that of control treatment after 1 day,3days, 5days,but lower than control treatment after 7 days;activity of POD were observably higher than that of control,but lower observably than control treatment after 5 days;activity of CAT were higher than that of control,but lower observably than control treatment after 13 days.It maybe concluded that activity of protective enzymes in leaves were all higher than those of control during early period of applying pesticide,plant maybe induce stress effect on pesticide;during later period applying pesticide,activity of protect enzymes were lower comparing with control because of pesticide destroying the protective enzymes in plant. Under pesticide stress,the change of activity of protective enzymes in striped flea beetle were different from those in Brassica campestris ssp.chinensis(L.).Compared with control,SOD and POD activity in striped flea beetle were both increased during early days after applying pesticide,then lowered,lastly rose again.The change trend of CAT activity treated by three pesticides were inconsistent early days,but were higher than control later days(11day,14day).Thus it can be seen protective enzyme activity in striped flea beetle raised in different degree under pesticide stress,which made striped flea beetle insensitive to pesticide.This result can provide powerful evidence to pest resurgence after applying pesticide.