EFFECT OF Cr(Ⅵ)STRESS ON ROOT EXUDATES AND MICROBIAL COMPOSITION OF LEERSIA HEXANDRA SWARTZ
To investigate the response mechanism of root secretions of Leersia hexandra Swartz to Cr(Ⅵ)and identify the key microorganisms in Cr(Ⅵ)reduction,in this study,the types and contents of organic matters secreted by the roots of L.hexandra in an artificial wetland-microbial fuel cell(CW-MFC)system were studied at six Cr(Ⅵ)treatment levels(0,40,60,80,100,120 mg/L).Soil microorganisms in the system were measured simultaneously at the control and optimal chromium treatment concentrations.The results showed that:1)the effect of chromium stress on the root secretion of L.hexandra showed an increasing trend followed by a decreasing trend during the increase of chromium concentration,with the highest quantity of compounds in the root secretion at a hexavalent chromium treatment concentration of 80 mg/L;2)the roots of L.hexandra were mainly lipids,alkanes,phenols,alkenes,and alcohols,of which alkanes were the most abundant;3)hexavalent chromium stress significantly increased the enrichment of Geobacter in the CW-MFC system,which may be the key microorganism associated with chromium reduction and enrichment in L.hexandra.
NETL
NSTL
万方数据
