Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China.
Sci Rep. 2017 Aug 2;7(1):7130. doi: 10.1038/s41598-017-07413-3.
Root exudates play an important role in the phytoremediation of soils contaminated by organic pollutants, but how root exudate components affect the remediation process is not well understood. In this study, we explored the effects and mechanisms of the major root exudates, including glucose, organic acids, and serine, in the rhizoremediation of pyrene-contaminated soil. The results showed that glucose increased the degradation of pyrene (54.3 ± 1.7%) most significantly compared to the organic acids (45.5 ± 2.5%) and serine (43.2 ± 0.1%). Glucose could significantly facilitate the removal of pyrene in soil through promoting dehydrogenase activity indicated by a positive correlation between the removal efficiency of pyrene and the soil dehydrogenase activity (p < 0.01). Furthermore, root exudates were able to change soil microbial community, particularly the bacterial taxonomic composition, thereby affecting the biodegradation of pyrene. Glucose could alter soil microbial community and enhance the amount of Mycobacterium markedly, which is dominant in the degradation of pyrene. These findings provide insights into the mechanisms by which root exudates enhance the degradation of organic contaminants and advance our understanding of the micro-processes involved in rhizoremediation.
根系分泌物在受有机污染物污染土壤的植物修复中起着重要作用，但根系分泌物成分如何影响修复过程还不太清楚。在这项研究中，我们探讨了主要根系分泌物（包括葡萄糖、有机酸和丝氨酸）在芘污染土壤的根际修复中的作用和机制。结果表明，与有机酸（45.5±2.5%）和丝氨酸（43.2±0.1%）相比，葡萄糖显著增加了芘的降解（54.3±1.7%）。葡萄糖通过促进脱氢酶活性（芘去除效率与土壤脱氢酶活性之间呈正相关，p<0.01）显著促进了土壤中芘的去除。此外，根系分泌物能够改变土壤微生物群落，特别是细菌分类组成，从而影响芘的生物降解。葡萄糖可以改变土壤微生物群落，显著增加在芘降解中占优势的分枝杆菌数量。这些发现为根系分泌物增强有机污染物降解的机制提供了新的见解，并加深了我们对根际修复中涉及的微观过程的理解。
