College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource, Nanjing Agricultural University, Nanjing 210095, China; National Joint Local Engineering Research Center for Rural Land Resources Use and Consolidation, Nanjing Agricultural University, Nanjing 210095, China.
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource, Nanjing Agricultural University, Nanjing 210095, China; National Joint Local Engineering Research Center for Rural Land Resources Use and Consolidation, Nanjing Agricultural University, Nanjing 210095, China.
Chemosphere. 2019 Jan;215:115-123. doi: 10.1016/j.chemosphere.2018.09.143. Epub 2018 Oct 4.
Whether the huge external hyphal system of ectomycorrhizae that promotes host plants' acquisition of water and nutrients can selectively inhibit their transport of heavy metals at the same time remains unclear. In this experiment, we designed and conducted two types of soil-pot test to clarify the effects of EMF on the absorption and transport of copper (Cu) and cadmium (Cd) by host Pinus thunbergii seedlings. In the root-bag test, external hyphae took the initiative into the Cu/Cd-contaminated bulk soil, absorb and transport Cu and Cd to the rhizosphere soils and further transport it to the shoots of the host plants. Inoculation with EMF also promoted the uptake of nutrients by host plants, thereby increasing their biomass and improving Cu/Cd tolerance compared with non-inoculated plants. Inoculation with EMF species with higher Cu or Cd tolerance generated more phytostabilization and phytoextraction of Cu or Cd by host plants. In a short-term exposure test, inoculation with EMF accelerated the absorption of Cu and Cd by P. thunbergii within 12 h of Cu or Cd irrigation. Therefore, we concluded that EMF do not act as a barrier inhibiting the absorption of heavy metals by host plants, but rather promote this absorption. Improving the plant's nutritional status and promoting growth, diluting heavy metal concentrations, thereby reducing the toxic effects of heavy metals on host plants. These results provide the theoretical basis for the application of EMF in plant-microbial combinations for the phytostabilization and phytoextraction of heavy metal-contaminated soils.
外生菌根巨大的菌丝系统是否能同时选择性地抑制宿主植物对重金属的运输，目前尚不清楚。在这项实验中，我们设计并进行了两种土培盆栽试验，以阐明外生菌根真菌（EMF）对宿主黑松幼苗吸收和转运铜（Cu）和镉（Cd）的影响。在根袋试验中，外生菌丝主动进入 Cu/Cd 污染的原状土壤，吸收和转运 Cu 和 Cd 到根际土壤，并进一步转运到宿主植物的地上部分。接种 EMF 还促进了宿主植物对养分的吸收，从而增加了它们的生物量，并提高了 Cu/Cd 耐受性，与未接种植物相比。具有更高 Cu 或 Cd 耐受性的 EMF 物种的接种，通过宿主植物对 Cu 或 Cd 的植物稳定化和植物提取作用更强。在短期暴露试验中，接种 EMF 在 Cu 或 Cd 灌溉后 12 小时内加速了黑松对 Cu 和 Cd 的吸收。因此，我们得出结论，EMF 不会作为一种屏障来抑制宿主植物对重金属的吸收，而是促进这种吸收。改善植物的营养状况和促进生长，稀释重金属浓度，从而减少重金属对宿主植物的毒性作用。这些结果为 EMF 在植物-微生物组合中用于重金属污染土壤的植物稳定化和植物提取提供了理论依据。
