根分泌物在污染土壤生物修复中的作用

对根分泌物在植物根际微生态环境中 ,通过土壤 植物 微生物系统协同作用高效修复重金属和有机污染土壤的环境过程与机理进行了综述。根分泌物在重金属污染土壤植物修复中的作用主要表现在活化污染区重金属元素 ,使固定态转化为植物可吸收态 ,大大提高了重金属的植物有效性 ,通过植物的超积累作用 ,降低土壤中重金属污染物的含量 ;此外 ,根分泌物也可以和重金属形成稳定的螯合体 ,降低他们在土壤中的移动性 ,起到固定和钝化作用。对于有机污染物 ,根分泌物一方面为根际的微生物提供了丰富的营养和能源 ,使植物根际的微生物数量和代谢活力比非根际区高 ,增强了微生物对环境中的有机污染物的降解能力 ;另一方面植物根分泌到根际的酶系统可直接参与有机污染物降解的生化过程 ,提高降解效率。并对此领域今后研究工作的方向做了探讨

Effects of root exudates in the bioremediation of contaminated soils

As one of the important components of microecosystem in rhizosphere,root exudates play an important role in the effective and enhanced bioremediation of contaminated soils through the combined interaction of soil,plant and microorganism.Root exudates can not only activate heavy metal pollutions to enhance their bioavailability in rhizosphere and plant uptake efficiency,but also provide abundant nutrition and energy to microorganism to increase the biomass and activity of microorganism,and thus promote the biodegradation of organic pollutions in soil environment.On the other hand,root exudates can immobilize and fix the heavy metals to reduce their environmental risk by chelating them.In addition,the enzymes that the root secreted can degrade organic pollutions directly.At last,some key points were suggested for further studies in this field.