黑麦草根系分泌物对根际微生物降解有机氯农药的效应

Effect of Exudates from Ryegrass Roots on Organochlorine Degradation by Rhizospheric Microbes

通过盆栽模拟试验,研究黑麦草Lolium multiforum的根系分泌物对根际微生物降解有机氯农药(Organochlorine pesticides,OCPs)的影响效应。结果显示,在供试OCPs含量(0~343.61 mg·kg^(-1))范围内,根系分泌物介导下植物-土壤-微生物系统(TR^2)对OCPs污染物的去除具有明显的促进作用:3个处理中,TR^2对OCPs的去除率最高(77.57%),较对照组(CK)高出33.49%,较土壤微生物活性被抑制的植物-土壤系统(TR1)高出58.16%。借助细菌计数法对根际微生物数量的检测结果则显示,相同污染水平下,TR^2系统里微生物数量最多,CK次之,TR1最少。说明黑麦草的根系分泌物对OCPs去除效果的促进作用可能与根际微生物种群数量的变化有关:根系分泌物的存在提高了根际微生物的种群数量,其降解效能随之提高。

Pot experiments were conducted to investigate effect of the exudates from roots of ryegrass（Lolium multiforum）on microbial degradation of organochlorine pesticide（OCP）residues in rhizospheric soil.The results showed that,within the tested concentrations of 0-343.61 mg·kg^（-1）,the exudates exhibited a significant enhancement on OCPs degradation in the soil.And,the highest OCPs removal rate at 77.57% was achieved when the root exudates were added in the presence of rhizospheric microbes;whereas,without the exudates,the removal rate was merely 33.49%,and it was 58.16%in the soil spiked with 0.05% NaN3 to suppress the microbial effect.Furthermore,under a same level of the pesticide stress,the microflora population increased with increasing exudates concentration in the soil suggesting that phytoremediation of the ryegrass under stress might also encourage the growth and metabolism of the rhizospheric microbes leading to the improved OCPs degradation.