有机磷混合农药的毒性及其机理的初步研究

测定NIA_(16388)和敌百虫与马拉硫磷混剂对玉米螟及大白鼠的毒性表明,马敌混剂对大白鼠的增毒效应大于对玉米螟,马敌混剂中加入增效剂NIA_(16388),进一步提高了对玉米螟的毒性,但对大白鼠的毒性则下降。研究这些杀虫剂对~(14)C-马拉硫磷降解影响的结果表明,NIA_(16388)和敌百虫均降低玉米螟及大白鼠肝羧酸酯酶降解~(14)C-马拉硫磷的活性。马敌混剂中加入NIA_(16388)对玉米螟羧酸酯酶降解~(14)C-马拉硫磷有更强的抑制效应,而这种混剂却使大白鼠肝羧酸酯酶降解~(14)C-马拉硫磷的活性增加。由此可见,这些有机磷混剂的增效作用似乎与羧酸酯酶的受抑制程度有关,它们的选择性毒性可能是由于玉米螟和大白鼠肝酶系的敏感性有差异所致。

PRELIMINARY STUDY ON TOXICITY AND ITS MECHANISM OF THE MIXTURES OF ORGANOPHOSPHATES

The toxicity of NIA and Dipterex,Malathion and their mixture was examined by using corn borer (Ostrinia furnacalis Guenee) and rat(S.D).The mixture of Malathion and Dipterex increased the toxicity remarkably to rat than to corn borer.When the mixture of Malathion and Dipterex plus synergist NIA was applied,the toxicity further enhanced to corn borer,but rather lowered to rat.The effects on degradating 14C-Mal-athion by these organophosphates was determined in vitro.The results sh-owed that NIA and Dipterex decreased the hydrolysate of 14C-Malathion by the homogenate of corn borer or rat liver.The inhibition of degradating 14C-Malathidn in corn borer was higher by the mixture of Malathion and Diptuerex plus NIA than by using Malathion and Dipterex alone.However,the combination of these organophosphates increased the formation of carboxylic product of Malathion when the homogenate of rat liver was used.It seemd that the synergism of the mixture of these organophosphates was related to the inhibition of C.Their selective toxiciti-es may be due to the different sensitivities of metabolic enzymes between corn borer and rat. Insecticides,mixture,carboxylesterase