水稻根系对非电离性农药的吸收、转移、分配与农药亲脂性的关系

研究了水稻根系对溶液中非电离农药的吸收、转移和在植株各部位的分配与农药亲脂性的关系。结果表明:亲脂性小的农药(Log Kow<1)在水稻根系中的浓度系数(RCF)的低限值约为1;当Log Kow>1时,RCF随LogKow值的增加而增加。亲脂性中等的农药(Log Kow 1.5—2.0)在蒸腾流中浓度系数(TSCF)最大;Log Kow值过大或过小,TSCF值都降低。不同亲脂性农药在水稻植株各部位的分配比例不同。Log Kow=1左右,农药被有效地转移并分配到叶部;Log Kow>3.5,农药几乎全部滞留于根和茎的基部。

RELATIONSHIPS BETWEEN LIPOPHILICITY AND ROOT UPTAKE AND TRANSLOCATION OF NON-IONISED CHEMICALS BY RICE

The relationships between lipophilicity of non-ionised chemicals ( estimated using Octanol/Water Partition Coef f icientsKow ) and their uptake by roots from nutrition solution ( described by Root Concentration FactorsRCF ) , translocation ( described by Transpiration Stream Concentration FactorsTSCF ) and distribution(described by Percentage% ) in rice plants were studied. The results showed that the polar chemicals (Log Kow1, the RCF values-increased with increasing lipophilicity. Translocation was most effective for the chemicals with intermediate lipophilicity. The maximum TSCF value at Log Kow was 1.5-2.0. Very polar and li-pophilic chemicals were poorly translocated.The percentage distribution in different parts of rice plants varied with lipophilicities. The chemicals of Log Kow circa 1 were most effectively translocated and distributed into leaves, but the chemicals with Log Kow values higher than 3.5 almost remained in roots and base of the stem