Facilitation of pentachlorophenol degradation in the rhizosphere of ryegrass (Lolium perenne L.)
Facilitation of pentachlorophenol degradation in the rhizosphere of ryegrass (Lolium perenne L.)
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DOI：
10.1016/j.soilbio.2005.03.002
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发表时间：
2005-11
影响因子：
9.7
通讯作者：
Yan He;Jianming Xu;Caixian Tang;Yuping Wu
中科院分区：
文献类型：
--
作者：
Yan He;Jianming Xu;Caixian Tang;Yuping Wu
外源性污染物的植物修复依赖于根际微生物与植物的相互作用，但其影响的程度和强度目前尚不清楚。为了研究根际环境对外源性物质生物降解的影响，采用一种特殊设计的根际箱进行了温室实验，其中黑麦草幼苗在添加浓度为8.7±0.5和18±0.5mgkg-1土壤的五氯酚（PCP）的土壤中生长53天。根箱中的土壤在离根表面不同的距离处被分成六个独立的室。然后评估了五氯苯酚浓度随离根箱根室距离的增加而发生的变化。种植土壤中五氯苯酚的最大和最快损失是在距离根区3 mm处，两种五氯苯酚处理的五氯苯酚总量分别降至0.20和0.65mgkg−1。两种浓度的降解梯度均为近根际>根际>远根际。相比之下，在未种植的土壤中，五氯苯酚浓度随距离的变化没有差异。土壤微生物生物量碳、土壤脲酶和磷酸酶活性的增加都伴随着PCP降解的增强，且近根际土壤PCP降解速率高于远根际土壤。结果表明，根际效应对土壤中五氯苯酚等外源性污染物的降解具有重要影响。
The phytoremediation of xenobiotics depends upon plant-microbe interactions in the rhizosphere, but the extent and intensity of these effects are currently unknown. To investigate rhizosphere effects on the biodegradation of xenobiotics, a glasshouse experiment was conducted using a specially designed rhizobox where ryegrass seedlings were grown for 53 days in a soil spiked with pentachlorophenol (PCP) at concentrations of 8.7±0.5 and 18±0.5mgkg−1soil. The soil in the rhizobox was divided into six separate compartments at various distances from the root surface. Changes in PCP concentrations with increasing distance from the root compartment of the rhizobox were then assessed. The largest and most rapid loss of PCP in planted soil was at 3mm from the root zone where total PCP decreased to 0.20 and 0.65mgkg−1, respectively with the two PCP treatments. The degradation gradient followed the order: near-rhizosphere>root compartment>far-rhizosphere soil zones for both concentrations where ryegrass was grown. In contrast, there was no difference in PCP concentration with distance in the unplanted soil. The increases in both soil microbial biomass carbon and the activities of soil urease and phosphatase were accompanied by the enhanced degradation of PCP, which was higher in the near-rhizosphere than far-rhizosphere soil. The results suggest that the effect of root proximity is important in the degradation of xenobiotics such as PCP in soil.