六氯苯胁迫对干湿交替运行人工湿地典型植物根系分泌物的影响

构建人工湿地微宇宙根箱,对六氯苯(Hexachlorobenzene,HCB)胁迫下不同水分条件的人工湿地典型植物——芦苇(Phragmites australis)和香蒲(Typha angustifolia)土壤中根系分泌物总糖、蛋白质和氨基酸进行检测,分析两种湿地植物根系分泌物在干湿交替下的变化特征。结果表明:芦苇和香蒲具有明显的根际效应(R/S1),根系分泌物含量变幅为根际土近根际土远根际土,且氨基酸∶蛋白质∶总糖含量的比值为2.9∶3.9∶3.3;香蒲根系分泌物含量高于芦苇,两者差异不显著(P0.05);排水(Water draining,WD)条件较淹水(Water flooding,WF)条件能显著增加芦苇和香蒲的根系分泌物(P0.05)。干湿交替更有利于促进芦苇和香蒲根系分泌物的增加及HCB降解,能促进水生植物形成较好的根际环境,进而影响湿地系统对HCB的去除效果。

Effects on root exudates of typical macrophytes operating in dry-wet alternation constructed wetlands under hexachlorobenzene stress

In order to understand water condition how to effect on root exudates of Phragmites australis(P. australis) and Typha angustifolia(T. angustifolia) in constructed wetland under HCB stress, we built the constructed wetland mesocosms to test the soil root exudates of typical plants in dry-wet alternation condition. The results showed that both of the P. australis and T. angustifolia had significantly rhizosphere effects(R/S>1), the contents of root exudates were:the rhizosphere > near the rhizosphere > far from the rhizosphere and moreover, the ratio of total suger, protein and amino acid contents was:2.9:3.9:3.3,however, rhizosphere effects of T. angustifolia were more obvious than P. australis. Water draining more significantly increased the root exudates of P. australis and T. angustifolia(P<0.05) than water flooding. This study indicated that the dry-wet alternation was more advantageous to promote the increased secretion both of P. australis and T. Angustifolia and the degradation of HCB than water draining and water flooding, could be in favor of creating a better rhizosphere environment, and then affect the removal efficiency of HCB in the wetland system.