有机酸在植物对重金属耐性和解毒机制中的作用

A review of progress in roles of organic acids on heavy metal resistance and detoxification in plants

植物对重金属的耐受和解毒机制可分为外部排斥和内部耐受两大类。该文综述了有机酸作为一类金属配位体,在植物对重金属的这两大类机制中的重要作用。在重金属的外部排斥过程中,植物根系分泌有机酸,与金属离子形成稳定的金属配位体复合物,改变重金属的移动性和生物可利用性,阻止金属离子进入植物体内或避免其在根部敏感位点累积。此外,有机酸还可与进入植物体内的金属离子螯合,使其转化为无毒或毒性较小的结合形态,缓解重金属的毒害效应,实现植物对重金属的内部耐受。

Mechanisms of heavy metal tolerance and detoxification in plants can be divided into two categories,external exclusion and internal tolerance.We reviewed the effects of organic acids as a kind of metal chelators in both processes in plants.In the external detoxification process,organic acids excreted from plant roots may form stable metal-ligand complexes with heavy metal ions and change their mobility and bioavailability,thus preventing the metal ions entering plants or avoiding their accumulation in the sensitive sites of roots.In internal metal detoxification,organic acids may chelate with heavy metal in cytosol,where the ions can be transformed into a non-toxic or less toxic form.