Toxicological Effects Of Pesticide On Photosystem Ⅱ In No-heading Chinese Cabbage

In view of problem about pesticide residual leads to pollution in vegetables,the chlorophyll a fluorescence transients were measured by a Plant Efficiency Analyzer(PEA; Hansatech Ltd.,King's Lynn,Norfolk,England)in no-heading Chinese cabbage,and the phtosystemⅡbehavior was analysed according to the JIP-test,in order to probing pollution ecology effects of pesticide in vegetables.The toxicological effects and rudimental dynamic courses on photosystemⅡ(PSⅡ)were investigated in no-heading chinese cabbage by using organic phosphorus pesticide "omethoate", "parathion","phorate","phoxime".Then,PSⅡtoxicological effects of Pesticides existing differences with different types and concentration after spraying pesticide with different brands and various concentrations on the leaves of no-heading Chinese cabbage.It is showed that Chlorophyll fluorescence dynamics curve is still typical four-phase of the OJIP,after spraying pesticide with different brands and various concentrations on the leaves of no-heading Chinese cabbage,and the value of a four-phase of the O,J,I,P of chlorophyll fluorescence dynamics has changed,omethoate,phorate,phoxim, chlorpyrifos,cypermethrin and shijiening are higher than that of control,besides parathion is lower.However the maximal efficiency of photo-chemistry(Fv/Fm)was not changed.The V_j related to J phase and ET_o/RC used for electron transport flux per reactive center in PSⅡwas increased with increasing of omethoate and phorate concentration. Moreover,the results showed uniform effects on behavior of photosystemⅡusing two brands of omethoate and phorate pesticide in no-heading chinese cabbage.The residual behavior disappeared gradually between nine and twelve days after spraying pesticide. Parathion and phoxime can reduce of parameters V_j in relation to J phase,and can also increase of ET_o/RC with increasing of concentration.Moreover,the results showed uniform effects on behavior of photosystemⅡusing two brands of parathion and phoxime pesticide in no-heading chinese cabbage.The residual behavior disappeared gradually between nine and twelve days after spraying pesticide.Chlorpyrifos and cypermethrin can reduce of parameters V_j in relation to J phase,and can also reduce of ET_o/RC with increasing of concentration.Moreover,the results showed uniform effects on behavior of photosystemⅡusing three brands of chlorpyrifos and two brands of cypermethrin pesticide in no-heading chinese cabbage.The residual behavior disappeared gradually between nine and twelve days after spraying pesticide.The V_j related to J phase was increased and ET_o/RC was reduced with increasing of shijiening concentration.The residual behavior disappeared gradually between nine and twelve days after spraying pesticide.The efficacy of three kinds of pesticides wasn't affected from additives.The effects which produced by organic phosphorus pesticide is that omethoate, phorate and shijiening can promote reducing from Q_A to Q_A~- in PSⅡ,e.g.increase of parameters V_j,the effect of parathion,phoxime,chlorpyrifos and cypermethrin are oppositional,And omethoate,phorate,parathion,phoxime,chlorpyrifos and cypermethrin can electron transmission from Q_A~- to Q_B in PSⅡ,e.g.increase of parameters ETo/RC,while shijiening checks electron transmission from Q_A~- to Q_B in PSⅡ.This because thatψ_o,the efficiency of exciton was captured by core in PSⅡmoves an electron into the electron transport chain and DIo/RC,the dissipated energy flux per reactive center.are complementary and regulative.In addition,Phorate and parathion harvest handling,storage of frozen storage at room temperature as the chlorophyll fluorescence of large implications.Omethoate, Cypermethrin and parathion additive does not affect its basic effect.