菲对黑麦草根系几种低分子量分泌物的影响

Effect of phenanthrene on the secretion of low molecule weight organic compounds by ryegrass root

有机污染的植物修复过程与植物根系分泌密切相关,近年来,对于持久性有机污染多环芳烃的植物修复研究得到了很大发展,但对于多环芳烃污染下植物根系分泌物的研究很少。该实验以多年生黑麦草(Lolium perenne L.)为供试材料,以营养液栽培方式研究了在多环芳烃菲处理下,黑麦草根系对几种低分子量有机物的分泌情况。研究结果显示,黑麦草根系分泌有机酸、总糖以及氨基酸的量都随菲质量浓度的上升而变化。黑麦草根系分泌的低分子有机酸主要为草酸,在菲处理下,低分子有机酸的组成无明显变化,但含量随菲质量浓度上升而提高(由对照时的2.33mg·g-1FW升高至8mg·L-1时的4.75mg·g-1FW);总糖和氨基酸含量均随菲质量浓度上升出现先升高后下降的趋势,但是最高值出现的菲质量浓度不同,从含量上来看,有机酸是黑麦草根系低分子量分泌物的主要部分。结合其它研究结果分析,植物分泌的有机酸可能在加速多环芳烃清除中发挥了重要作用。

The phytoremediation of organic pollutants is closely related to root secretion. In recent years, there are large numbers of researches concerned about phytoremedation of polycyclic aromatic hydrocarbons; however, few of them are about the root secretion under polycyclic aromatic hydrocarbons stress. In this research, a solution culture experiment was performed to investigate the impact of phenantherene on several low molecular weight organic components in ryegrass （Lolium perenne L.） root exudates. Data showed that, organic acids, total carbohydrate and amino acids all changed in quantity under phenantherene stress. Oxlic acid was the main composition of organic acid in root exudates, and its content increased with the phenantherene concentration rising （range from 2.33 to 4.75 mg·g^-1 FW）; tota! carbohydrate and amino acids in root exudates showed similar change trend, at relatively low phenantherene concentrations their quantities raised and at relatively high treatments, their quantities reduced. As a whole, organic acids were the main part of low molecular weight organic component in ryegrass root exudates, and combing with other researches, we suggested that the increased organic acids secretion may also play an important role in polycyclic aromatic hydrocarbons phytoremediation.