磺酰脲类除草剂的化学作用方式选择及降解特性

The Chemistry Mode of Action, Crop Selectivity Characteristics of Degradation of Sulfonylurea Herbicides

磺酰脲类除草剂具有广谱性 ,用量极低 ,选择性强和低的急慢性毒性。这类除草剂抑制乙酰乳酸合成酶 ,阻止支链氨基酸缬氨酸、亮氨酸、异亮氨酸的生物合成 ,导致植物细胞停止分裂和生长。作物的选择性由耐性作物的快速钝化代谢而引起。该类除草剂在土壤中降解是通过脲桥水解和微生物降解的共同作用 。

The sulfonylurea herbicides are characterized by broad spctrum weed control at very low use rates, good crop selectivity,and very low acute and chronic animal toxicity. This class of herbicides acts through inhibition of acetolactate synthase, thereby blocking the biosynthesis of the branched chain amino acids valine,leucine and isoleucine. This inhibiton leads to the rapid cessation of plant cell division and growth. Crop selectivity results from rapid metabolic inactivation of the herbicide in the tolerant crop. Sulfonylurea herbicides degrade in soil through a combination of bridge hydrolysis and microbial degradation. Otherwise, hydrolysis is significantly faster under acidic than alkaline conditions.