丛枝菌根对翅荚木生长及吸收累积重金属的影响

针对湖南某铅锌矿区土壤重金属污染严重问题,采用温室盆栽的方法,以该矿区污染土壤为基质,先锋植物翅荚木(Zenia insignis Chun)为宿主植物,研究摩西球囊霉(Glomus mosseae,Gm)和根内球囊霉(G.intraradices,Gi)两种丛枝菌根(Arbuscular Mycorrhizal,AM)真菌对翅荚木生长和吸收累积重金属的影响.结果表明,重金属污染条件下,两种AM真菌均能与翅荚木形成良好的共生关系,且AM真菌能够显著促进植物吸收磷,增加植物生物量,同时改变植物重金属吸收及分配.总体来说,AM降低了翅荚木体内Fe、Cu、Zn和Pd浓度,同时增加了Fe、Cu、Zn和Pd累积量.而两种AM真菌对植物体内重金属分配影响并不相同,而且受重金属种类影响,接种Gi降低了植物Fe、Zn和Pb的TF值,而接种Gm对植物Zn和Pb的TF值无影响,两种AM真菌对植物Cu的TF值均无影响,表明Gi具有能够强化翅荚木根系固持Fe、Zn和Pb的能力.本研究表明,AM真菌在翅荚木适应重金属污染中起着重要的积极作用,因而在重金属污染土壤的植物修复中具有极高的潜在应用价值,但在具体应用中需考虑菌种和植物组合及重金属类型等因素.

Effect of Arbuscular Mycorrhizae on Growth, Heavy Metal Uptake and Accumulation of Zenia insignis Chun Seedlings

To solve the trace metal pollution of a Pd/Zn mine in Hunan province, a greenhouse pot experiment was conducted to investigate the effect of two arbuscular mycorrhizal fungi, Glomus mosseae (Gm) and Glomus intraradices (Gi), on the growth, heavy metal uptake and accumulation of Zenia insignis Chun, the pioneer plant there. The results showed that symbiotic associations were successfully established between the two isolates and Z. insignis in heavy metal contaminated soil. AM fungi improved P absorption, biomass and changed heavy metal uptake and distribution of Z. insignis. AM fungi-inoculated plants had significantly lower Fe, Cu, Zn, Pd concentrations and higher Fe, Cu, Zn, Pd accumulation than non-inoculated plants. However, Gm and Gi showed different mycorrhizal effects on the distribution of heavy metal in hosts, depending on the species of heavy metal. Gi-inoculated Z. insignis showed significantly lower TF values of Fe, Zn, Pd than Gm and non-inoculated plants, while both strains had no effect on TF value of Cu, which indicated that Gi enhanced trace metal accumulation in root system, playing a filtering/sequestering role in the presence of trace metals. The overall results demonstrated that AM fungi had positive effect on Z. insignis in enhancing the ability to adapt the heavy metal contaminated soil and played potential role in the revegetation of heavy metal contaminated soil. But in practical application, the combination of AM, hosts and heavy metal should be considered.