MOE Key Laboratory of Environment Remediation and Ecosystem Health, College of Environmental and Resources Science, Zhejiang University, Zijingang Campus, Hangzhou 310058, China.
J Hazard Mater. 2012 Aug 30;229-230:361-70. doi: 10.1016/j.jhazmat.2012.06.013. Epub 2012 Jun 16.
Low biomass and shallow root systems limit the application of heavy metal phytoextraction by hyperaccumulators. Plant growth-promoting microbes may enhance hyperaccumulators'phytoextraction. A heavy metal-resistant fungus belonged to the Fusarium oxysporum complex was isolated from the Zn/Cd co-hyperaccumulator Sedum alfredii Hance grown in a Pb/Zn mined area. This Fusarium fungus was not pathogenic to plants but promoted host growth. Hydroponic experiments showed that 500 μM Zn(2+) or 50 μM Cd(2+) combined with the fungus increased root length, branches, and surface areas, enhanced nutrient uptake and chlorophyll synthesis, leading to more vigorous hyperaccumulators with greater root systems. Soil experiments showed that the fungus increased root and shoot biomass and S. alfredii-mediated heavy metal availabilities, uptake, translocation or concentrations, and thus increased phytoextraction of Zn (144% and 44%), Cd (139% and 55%), Pb (84% and 85%) and Cu (63% and 77%) from the original Pb/Zn mined soil and a multi-metal contaminated paddy soil. Together, the nonpathogenic Fusarium fungus was able to increase S. alfredii root systems and function, metal availability and accumulation, plant biomass, and thus phytoextraction efficiency. This study showed a great application potential for culturable indigenous fungi other than symbiotic mycorrhizas to enhance the phytoextraction by hyperaccumulators.
低生物量和浅根系限制了超积累植物对重金属的植物提取应用。植物促生微生物可以增强超积累植物的植物提取能力。从 Pb/Zn 矿区生长的 Zn/Cd 共超积累植物景天属 Sedum alfredii Hance 中分离到一种属于尖孢镰刀菌复合体的耐重金属真菌。该尖孢镰刀菌对植物没有致病性，但能促进宿主生长。水培实验表明，500μM Zn(2+)或 50μM Cd(2+)与真菌结合可增加根长、分枝和表面积，增强养分吸收和叶绿素合成，使超积累植物根系更加发达。土壤实验表明，该真菌增加了根和地上部分的生物量，以及 S. alfredii 介导的重金属有效性、吸收、转运或浓度，从而增加了 Zn（144%和44%）、Cd（139%和55%）、Pb（84%和85%）和 Cu（63%和77%）从原始 Pb/Zn 矿区土壤和多金属污染稻田土壤中的提取。总之，非致病性尖孢镰刀菌能够增加 S. alfredii 的根系和功能、金属的有效性和积累、植物生物量，从而提高植物提取效率。本研究表明，可培养的土著真菌（不同于共生菌根真菌）在增强超积累植物的植物提取方面具有很大的应用潜力。
