茶树生长稀释在农药降解中的定量

Quantum of Growth Dilution by Tea Shoots in the Degradation of Pesticides on Tea Plant

本文报道了不同年度、季节和茶树品种新梢生长速率的差异及新梢生长对农药的稀释作用。研究表明,同一品种茶梢生长速率年度间差异不大,而不同季节和不同品种间有较大差异,不同生育年龄新梢的生长速率也有明显差异。还证明了新梢的生长速率常数即为其生长稀释速率常数。决定生长稀释速率的因子是田间茶树上不同生育年龄新梢的生长速率及茶园中各种新梢的比例。在同样的条件下,茶树生长稀释对不同农药所起的作用有很大差异。对残留期短的农药(如敌敌畏、辛硫磷、马拉硫磷),生长稀释在总降解中的作用不足10%,对杀螟硫磷、乐果、亚胺硫磷的作用约占20%,而对残留期长的联苯菊酯,氯氰菊酯,溴氰菊酯、三氯杀螨醇、乙硫磷的作用可达50%左右。本文还提出了茶园中新梢对农药的群体生长稀释速率常数的预测模型。

The effect of growth of tea shoots on the degradation of pesticideswere investigated in different years,seasons and tea varieties.Resultsshowed that there were insignificant differences in the growth rate ofthe shoots of the same variety with different years,but significant differ-ences with different seasons and varieties,and much more significantdifferences with different flushing-stage shoots.It was proved that thegrowth dilution rate constant could be expressed by the populative growthrate constant of the shoots,which was composed of the growth rate and thepercentage of various flushing-stage shoots in tea garden.The roles ofgrowth dilution by tea shoots on the degradation of pesticides were evalu-ated as follows:It took under 10% in the total degradation of thosepesticides with shorter residual life such as Dichlorvos,Phoxim and Mal-athion,about 20% in the degradation of Fenitrothion,Dimethoate,Phosmetand Quinalphos,and about 50% in the degradation of those persistentpesticides such as Biphenthrin,Deltamethrin,Cypermethrin,Fenvalerate,Dicofol and Ethion etc.A predictive model of the populative growth rateconstant of tea shoots was put forward by the authors.