Research On The Effects Of Composite Exogenous Substances Mitigating Crops Phytotoxicity Caused By Pesticide

Pesticides play key role in protecting crops from injuring from disease, pests and weeds in agricultural production. But if the pesticides are used improperly, they will not only be injured crops, but also the residues in crops may threat human health. In order to reduce phytotoxicity, the studies on pesticide safety have become the focus of attention at home and abroad.We studied one kind of pesticide security agent (composite exogenous substances) in order to reduce phytotoxicity for pesticides prone to injure crops in agricultural production.The studies included two parts. One was sieving pesticides prone to injure crops, and another was mitigating phytotoxicity with composite exogenous substances.The height, fresh weight, SPAD value, GSH content, and the activities of SOD,POD as well as CAT of Chinese cabbage leaves were measured to evaluate the remission effects of composite exogenous substances. The results showed as followed.1.There were nine pesticides prone to injure crops in agricultural production in 23 test pesticides, namely glyphosate, phoxim, butachlor, acetochlor,2,4-D, MCPA, mepiquat chloride, chlormequat chloride and paraquat. In which paraquat caused the most serious phytotoxicity, and Chinese cabbage withered basically. Next were glyphosate, 2,4-D, MCPA, mepiquat chloride and chlormequat chloride.However, less serious phytotoxicity happened in Chinese cabbage after the treatments of phoxim, acetochlor and butachlor. Other pesticides had basically no phytotoxicity.2.The experiments of mitigating phytotoxicity with composite exogenous substances were further carried out. The results showed that composite exogenous substances mitigated well phytotoxicity caused by glyphosate,2,4-D, MCPA, mepiquat chloride, chlormequat chloride as well as paraquat, and promoted the growth of Chinese cabbage. Composite exogenous substances induced the activity of antioxidant enzymes in Chinese cabbage and improved GSH contents so as to mitigate phytotoxicity. In addition, the increase in SPAD value after the treatment of composite exogenous substances was beneficial to enhance photosynthesis in Chinese cabbage.3.Composite exogenous substances had little mitigation for the phytotoxicity caused by phoxim, butachlor as well as acetochlor, but promoted the growth of Chinese cabbage by the increase in SPAD value. Composite exogenous substances can not mitigate the pesticide hazard caused by paraquat at all.4. The effects of composite exogenous substances on mitigating phytotoxicity were related to the concentration. Among all treatments, the treatment of diluted 800 times was the best, followed by the treatments of diluted 600 times and 1000 times...