采用紫外光谱法测定了多菌灵草酸盐和多菌灵分别处理棉苗后 ,对棉叶的穿透速率和在棉苗内的定量分布 ,以及这两种农药的油水分配系数 ,并用重量法测定了棉叶、棉根、茎韧皮部和木质部等生物样品的油水分配系数 ,结果表明 :多菌灵草酸盐在棉苗内具有双向传导作用 ,初步探明双向传导的本质原因是由于草酸羧基的引入 ,使其具有与棉苗各部位的油水分配系数更加接近的油水分配系数 ,根据相近相通原理 ,因而更容易穿透棉苗各部位 ,并进行双向传导 The penetration rate of cotton leaves and the quantitative distribution in the cotton seedlings and the oil-water partition coefficients of the two pesticides were determined by UV spectrophotometry after carbendazim and carbendazim were treated respectively. Method was used to determine the oil-water partition coefficient of biological samples such as cotton leaves, cotton roots, stem phloem and xylem. The results showed that carbendazim oxalate had two-way conduction in cotton seedlings. The basic reason for the bidirectional conduction was that oxalic acid The introduction of carboxyl, cotton oil so that it has parts of the oil and water distribution coefficients closer to the oil-water partition coefficient, according to the principle of similar interlinked, and thus more likely to penetrate the cotton seedlings in various parts and conduct bi-directional conduction