强化植物修复重金属污染土壤的策略及其机制

The Augmentation Strategies and Mechanisms in the Phytoremediation of Heavy Metal-contaminated Soil

重金属对生态环境、农业生产、人类健康等诸多方面造成重要危害。植物修复因其具有经济有效、绿色生态等优点,已经成为土壤重金属污染修复研究领域的热点。由于植物重金属毒害、修复耗时过长等因素致使植物修复技术受限于研究阶段而不能广泛应用于实践。采用科学合理的强化措施提高植物修复的效率可能是解决该矛盾的关键之一。讨论了根瘤菌、丛枝菌根真菌、溶磷微生物和内生真菌构建的微生物-植物共生系统在强化植物修复过程中的具体应用;概述了EDTA、EDDS等螯合剂在改变土壤中重金属可溶态,促进重金属从土壤向植株转运的重要作用;介绍了植物中编码金属转运蛋白、金属硫蛋白、植物螯合肽等与重金属转运和代谢相关的基因在植物修复领域的实际应用;归纳了上述强化策略主要机制为微生物促进植物生长、缓解重金属植物毒性以及提高了土壤中重金属生物利用度,从而促进重金属在富集植物中积累和植物生物量的增加;最后总结并展望了植物修复强化技术在今后研究的重点及存在的问题。综述植物修复技术采用的主要强化策略及其机制,旨在为利用植物修复技术治理土壤重金属污染提供重要参考。

Heavy metal pollution has posed a harmful influence on ecological environment,agricultural production,human health and many other aspects.Phytoremediation,a cost-effective and green ecological biotechnology,has been a research focus in the remediation of heavy metal-contaminated soil.Actually,most phytoremediation cases were limited to the lab research due to the factors such as heavy metal toxicity of plants and time consuming during the remediation process.Reasonable augmentation measures may enhance the phytoremediation efficiency,which may be a key to solve the problem mentioned above.Rhizobium,arbuscular mycorrhiza fungi,phosphate-solubilizing microbe,and endophytic fungi may construct the microbe-plants symbiotic system with plants as host,and the application of such microbeplants symbiotic system in phytoremediation field is discussed.Meanwhile,the function of chelating agents for enhancing phytoremediation efficiency is reviewed,for example,EDTA and EDDS etc.,with the ability to change the heavy metal solubility in the soil,prompt the heavy metals to transfer into plants from the soil.Genes encoding proteins involved in heavy metals transfer and metabolism,including metal transporter protein,metallothionein,and phytochelatins,are introduced about their applications in phytoremediation.The main mechanisms of the above-mentioned augmentation strategies are summarized as microbes promoting plant growth,alleviating the toxicity of heavy metal plants,and increasing the bioavailability of heavy metals in the soil,thereby promoting the over-accumulation of heavy metals in plants and the increase of plant biomass.Finally,the key research points and existing problems in phytoremediation augmentation technology in future are summarized and forecasted.This article systematically reviews the main augmentation strategies and mechanisms used in phytoremediation technology,aiming at providing an important reference for the use of phytoremediation technology to solve soil contamination by heavy metal.