Effects Of AM Fungi On The Growth Of Nitraria Sibirica In Heavy Metall Contaminated Saline Soils

In recent years,heavy metalcontaminated saline soils have become a worldwide environmental problem.Halophytes are tolerant to both heavy metals and salt stress and are potential remediation plants.AM fungi can significantly improve the tolerance of sweet soil plants to heavy metals or salt stress,and improve the phytoremediation efficiency of degraded soil.However,few studies have focused on the effects of AM fungi on growth and tolerance of Halophytes under combined stress of heavy metals and salt.In this paper,pot experiments were conducted in greenhouse to simulate the effects of inoculation of AMfungiF.mosseae on the growth,heavy metal uptake and transportation of Saline Plants Nitraria sibirica minimalis by simulating saline soils with different concentrations of Cd(0,2,5,10 mg·kg^-1)and saline soils with different concentrations of La-Cd(La:0,100 mg·kg^-1;Cd:0,5 mg·kg^-1).The results show that:?1?The symbiotic relationship between AM fungi and Nitraria sibirica was successfully established in saline soils polluted by Cd and La-Cd.The mycorrhizal infection rates were 13.9%-22.5%and21.51%-32.69%respectively,and 1.5 g·kg^-11 NaCl significantly reduced the infection rates by 30.5%-34.4%and 12.8%-33.9%.?2?In Cd-contaminated saline soil,AM fungi increased the biomass of Nitraria sibirica by 91.6%-215.3%and the contents of N,P and K in plants by 39.8%-450.5%.NaCl increased Cd concentration by49.6%-110.1%,AM fungi decreased Cd concentration by 31.4%-129.3%,and NaCl and AM fungi reduced Cd transport by 17.3%-38.6%.AM fungi significantly reduced Na⁺concentration by 33.1%-54.0%.In Na0treatment,AM fungi significantly reduced Na⁺transport rate by6.2%-6.9%.?3?NaCl and AM fungi had no significant effect on the biomass and P content of Nitraria sibirica in saline soil polluted by La-Cd.NaCl significantly increased Cd concentration of Nitraria sibirica in Cd5treatment by 21.4%-198.5%.AM fungi significantly decreased Cd concentration of Nitraria sibirica in Cd5 treatment by 21.4%-58.2%.AM fungi significantly decreased Cd transport rate by 12.5%-34.9%.NaCl significantly reduced La concentration in the shoots of La0Cd5 by 60.7%;AM fungi significantly reduced La concentration in the shoots of La0Cd5and Na0 by 55.3%;NaCl significantly reduced La transport rates in La0Cd0 and La0Cd5 treatments by 44.5%and 51.1%.AM fungi significantly increased Na⁺concentration in the shoots of La0Cd5 Na0 by32.2%,decreased Na⁺concentration in the shoots of La100Cd5 Na0 by35.5%,increased Na⁺concentration in the shoots of Cd0La0Na1.5 by18.5%,decreased Na⁺concentration in the shoots of La100Cd0 Na0 and La0Cd5 Na0 by 17.2%-36.3%in the non-AM fungi group,and decreased Na⁺concentration in the shoots by 15.8%-26.7%in the AM fungi group.Preliminary studies showed that AM fungi could significantly promote the growth of Nitraria sibirica in saline soil polluted by Cd,and affect the absorption and transport of mineral nutrients,heavy metal elements and Na⁺in soil.The results of this study will help to better understand the mechanism of AM fungi-halophytes combined remediation of saline soil contaminated by heavy metals,and provide basic data and theoretical basis for remediation and treatment.