Role Of Arbuscular Mycorrhizal Fungi In Plant Adaptation To Copper Mine Tailings

Mining activities resulted in large scale abandoned lands and many eco-environmental problems in mining area. Among the remediation strategies, ecological restoration was widely considered as an ideal countermeasure to mining impacted environments. In this paper application of mycorrhizal technology for revegetation of copper mine tailings was proposed and evaluated. Copper tailings collected from mining area were used as growth substrates, and series of pot experiments were conducted to reveal the potential role of arbuscular mycorrhizal fungi in plant adaptation to the harsh environment and to understand the underlying mechanisms.In the first experiment, mycorrhizal effects on growth and mineral nutrition of four plant species grown in copper tailings were investigated. The results indicated that except for perennial ryegrass (Lolium perenne L.), which develops extensive root system, golden-wave coreopsis (Coreopsis drummondii Torr. et Gray), Chinese brake fern (Pteris vittata L.) and white clover (Trifolium repens L.) greatly depended on mycorrhiza for adaptation to copper tailings. Without inoculation with mycorrhizal fungus, plant growth was very poor, while mycorrhizal colonization substantially increased plant dry biomass by several folds. Mycorrhiza also significantly stimulated plant P uptake, however due to the growth dilution effect, P concentrations in plant tissues were little affected. On the other hand, mycorrhiza significantly decreased Cu and Cd concentrations in all plant species except for ryegrass. The experiment demonstrated that arbuscular mycorrhiza can encourage plant survival on copper tailings by improving plant mineral nutrition and alleviation of potential metal phytotoxicity, and this was essential for plant species with strong mycorrhizal dependence.In the following experiment, effects of mycorrhizal colonization with each or both of the two fungal species, Glomus mosseae and Glomus versiforme on coexistence of white clover and ryegrass on copper mine tailings were investigated. The highest root colonization rate was recorded in clover plants among different treatments. Shoot dry weight and P content of clover plants was significantly increased, and Cu content was decreased, by mycorrhizal colonization irrespective of single or mixed culture of the two plant species, while growth and element uptake of ryegrass was hardly influenced by mycorrhiza. When growing in mixture, ryegrass showed competitive advantages against clover, while mycorrhiza improved competitiveness of clover plants. The results demonstrated that AMF may play...