The Effects Of Arbuscular Mycorrhizal Fungi On Soil Lead (Pb) Phytoremediation

In recent years,with the rapid development of the industrialization process,soil heavy metal(HM)pollution has become a global environmental problem.These HMs can accumulate in the human body through the food chain and endanger human health.Currently,how to repair heavy metal pollution in soil has become an important issue that needs to be solved urgently in the field of environmental science.Through the enrichment of heavy metals,plants can promote the transfer of HMs to the above-ground part without destroying the physical and chemical properties of the soil.The arbuscular mycorrhizal fungi are one of the vital soil microbes widely distributed in terrestrial ecosystems,capable to form a mutually advantageous symbiosis with more than 80% of terrestrial plants.AMF community composition and diversity has an important role in the maintenance of ecosystem function and stability.On the other hand,AMF have ability to promote plant growth and increase phytoremediation efficiency in HMs contaminated soils by enhancing plant nutrient absorption and influencing the fate of the metals in the plant and soil.In this study,a greenhouse control experiment was conducted to analyze the effect of AMF on the efficiency of Pb phytoremediation of Bidens parviflora.The main results obtained are as follows: soil Pb pollution significantly reduced the above-ground and root biomass of plants,while the dry weight of the above-ground and root system of mycorrhizal plants was higher than that of non-mycorrhizal plants;AMF inoculation increased the Pb concentration of plant roots,while it had no effect on the Pb concentration in the aerial part of the plant;soil Pb pollution significantly reduced the content of chlorophyll a and chlorophyll b in plant leaves,but AMF inoculation increased the content of chlorophyll a(11.7%)and chlorophyll b(5.8%);AMF increased the net photosynthetic rate,stomatal conductance and transpiration rate of plant leaves,but reduced the intercellular carbon dioxide concentration of plant leaves,thereby reducing the harm effect of Pb pollution to the plant photosynthesis;in addition,AMF alleviated the inhibition of N and P absorption by Pb pollution,but had no effect on plant K element absorption through affecting the phosphatase and urease activities of rhizosphere soil.In summary,this study shows that AMF can promote plant growth and affect the concentration and distribution characteristics of Pb by maintaining plant photosynthesis,enhancing plant element absorption,and increasing rhizosphere soil enzyme activities,thereby promoting phytoremediation for soil Pb pollution.Therefore,the use of plant-AMF combination brought the pronounced benefits in phytoremediation,providing a feasible strategy for HMs remediation in soils.