The roles of arbuscular mycorrhizal fungi (AMF) in phytoremediation and tree-herb interactions in Pb contaminated soil

Abstract

Understanding the roles of arbuscular mycorrhizal fungi (AMF) in plant interaction is essential for optimizing plant distribution to restore degraded ecosystems. This study investigated the effects of AMF and the presence of legume or grass herbs on phytoremediation with a legume tree, Robinia pseudoacacia, in Pb polluted soil. In monoculture, mycorrhizal dependency of legumes was higher than that of grass, and AMF benefited the plant biomass of legumes but had no effect on grass. Mycorrhizal colonization of plant was enhanced by legume neighbors but inhibited by grass neighbor in co-culture system. N, P, S and Mg concentrations of mycorrhizal legumes were larger than these of non-mycorrhizal legumes. Legume herbs decreased soil pH and thereby increased the Pb concentrations of plants. The neighbor effects of legumes shifted from negative to positive with increasing Pb stress levels, whereas grass provided a negative effect on the growth of legume tree. AMF enhanced the competition but equalized growth of legume-legume under unpolluted and Pb stress conditions, respectively. In conclusion, (1) AMF mediate plant interaction through directly influencing plant biomass, and/or indirectly influencing plant photosynthesis, macronutrient acquisition, (2) legume tree inoculated with AMF and co-planted with legume herbs provides an effective way for Pb phytoremediation.

Streptomyces pactum assisted phytoremediation in Zn/Pb smelter contaminated soil of Feng County and its impact on enzymatic activities

“…Biochar facilitated the adsorption (immobilization) of Pb in the soil solution, hence causing Pb translocation into sorghum roots1227. Yang et al 18. also reported increases in the uptake of Pb in the roots of different legumes in Pb-contaminated soil.…”

“…The higher Zn, Pb and Cd contents are attributed to the Zn/Pb smelting and mining activities in this area. Apart from the other PTEs, the production of recoverable Pb from mining operations in 2014 reached 2950 thousand metric tons in China18. The total Zn content in PMC and biochar was 1007.73 and 115.4 mg kg −1 , respectively.…”

“…Remediation of PTEs in soil contaminated by mines through physicochemical techniques is very expensive, laborious and unsuitable for larger mining sites. Therefore, phytoremediation assisted by biotechnological approaches in soil contaminated by smelters and mines has received great attention in recent years161718. The remediation potential of plants is expressed as the uptake of PTEs in the shoot/root and biomass produced19.…”

Microbial‐Enhanced Phytoremediation of Lead Contaminated Calcareous Soil by Centaurea cyanus L

“…Among alternatives to overcome these limitations is the use of specific microorganisms, such as arbuscular mycorrhizal fungi (AMF) and plant growth‐promoting rhizobacteria (PGPR) that form symbiotic associations with most land plants . AMF can improve growth and tolerance to stress conditions of host plants and increase the bioavailability of PTEs in soil, metal uptake by plants from soil and root‐to‐shoot translocation of absorbed metals .…”

“…AMF can improve growth and tolerance to stress conditions of host plants and increase the bioavailability of PTEs in soil, metal uptake by plants from soil and root‐to‐shoot translocation of absorbed metals . Therefore, AMF has been emerged as the most prominent symbiotic fungi for contribution to phytoremediation …”