Biotechnology Bulletin ›› 2023, Vol. 39 ›› Issue (8): 114-125.doi: 10.13560/j.cnki.biotech.bull.1985.2023-0125

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Research Progress in Mechanisms of Microbial-enhanced Phytoremediation for Lead-contaminated Soil

JIANG Run-hai(), JIANG Ran-ran, ZHU Cheng-qiang, HOU Xiu-li()   

  1. Yunnan Collaborative Innovation Center for Plateau Lake Ecology and Environmental Health, College of Agronomy and Life Sciences, Kunming University, Kunming 650214
  • Received:2023-02-15 Online:2023-08-26 Published:2023-09-05
  • Contact: HOU Xiu-li E-mail:1457113729@qq.com;hxlyn@aliyun.com

Abstract:

Lead(Pb)is one of the heavy metals that cause soil pollution and pose a serious threat to biological safety. Microorganisms play an important role in alleviating the toxicity of lead to plants. In the process of interacting with the rhizosphere, soil microorganisms improve the microecological environment of the rhizosphere and promote the repair of plants to lead and reduce the toxicity of lead by various means. This article focuses on the biochemical interaction between soil microorganisms and heavy metal lead, reviews the mechanism of microorganisms'role in repairing lead pollution in plants, and concludes as follows: 1)There are a large number of binding sites and negatively charged functional groups that have strong adsorption of lead on the cell walls of microorganisms. 2)Cations exchange ions with heavy metals in the process of interaction with heavy metals. 3)Microorganisms secret extracellular substances in metabolism, which form stable lead complexes with heavy metals. 4)The forms of heavy metals in soil are changed or transformed by oxidation-reduction reactions, or the lead are oxidized and reduced to insoluble precipitation, thus reducing the toxicity of heavy metals in soil. 5)The growth hormone secreted by microorganisms can promote the growth and development of plants, improve the resistance of plants, and its metabolic products can change the characteristics of heavy metals in the rhizosphere, which promotes the absorption of lead by plants or fix lead in the rhizosphere of plants to reduce the toxicity of lead to plants. A comprehensive discussion of the main mechanisms of lead adsorption by microorganisms was conducted, and the relationship between microorganisms and plants in the repair of lead pollution in soil was summarized, providing a basis for further understanding the interaction mechanism among plants, microorganisms and heavy metals in the process of soil heavy metal remediation.

Key words: microorganism, phytoremediation, lead, plant growth promotion, heavy metal stress, tolerance mechanisms