丛枝菌根真菌对紫花苜蓿吸收土壤中镉和锌的影响

采用温室盆栽试验方法,研究了镉(Cd)、锌(Zn)污染土壤中,8种不同丛枝菌根真菌( AMF)Glomus lamellosum(G.la)、Acaulospora mellea( A.m)、Glomus mosseae( G.m)、Glomus intraradices( G.i)、Glomus etunicatum( G.e)、Glomus constrictum( G.c)、Diversispora spurcum( D.s)、Glomus aggregatum( G.a)对紫花苜蓿(Medicagosativa L.)吸收Cd、Zn的影响.结果表明,Cd、Zn污染下AMF仍然明显侵染紫花苜蓿,并促进紫花苜蓿对Cd、Zn的吸收积累,但不同AMF影响的效应和植株不同部位对重金属的吸收积累规律存在差异.AMF处理下紫花苜蓿根部Cd、Zn含量和积累量明显增加,但地上部Cd、Zn的含量则降低,地上部Zn的积累量也减小,这表明AMF处理减弱了Cd、Zn由根部向地上部的运移,减轻了植物地上部毒害.接种AMF条件下,植株尤其是根部生物量增加是Cd、Zn在其体内含量和积累量增加的重要因素,不同种类AMF促进植株生物量增加的幅度不同,导致植株对Cd、Zn的积累和抗性存在差异.

Impacts of Arbuscular Mycorrhizal Fungi Inoculation on the Uptake of Cadmium and Zinc by Alfalfa in Contaminated Soil

Uptake of cadmium(Cd) and zinc(Zn) from soil by Alfalfa(Medicagosativa L.) inoculated with different arbuscular mycorrhizal fungi(AMF) was investigated utilizing a greenhouse experiment.The eight examined AMFs included Gloumus lamellosum(G.la),Acaulospora mellea(A.m),Glomus mosseae(G.m),Glomus intraradices(G.i),Glomus etunicatum(G.e),Glomus constrictum(G.c),Diversispora spurcum(D.s) and Glomus aggregatum(G.a).It was observed that the alfalfa roots were effectively colonized by AMFs even in the contaminated soil by Cd and Zn.The accumulation of Cd and Zn in plant was enhanced with AMF inoculation.However,mycorrhizal effects on plant growth and accumulation of Cd and Zn differed between test AMFs.Compared to no-AMF control,the concentration and accumulation amount of Cd and Zn increased in roots,but they decreased in shoots with the inoculation of AMFs.This indicates that AMF inoculation impeded the translocation of Cd and Zn from root to shoot,and consequently weakened the toxicity of these heavy metals to plant shoot.It was proposed that the increase of the plant biomass by AMF inoculation affected the enhancement of Cd and Zn concentration and accumulation in plant.Results of this work provided useful information on the AMF-based uptake of heavy metals by plants,and would potentially be helpful to risk assessment and food security in contaminated soils.