Glomus intraradices对黑麦草生长和富集镉的影响

Effects of Glomus intraradices on Growth and Cd Enrichment of Ryegrass(Lolium perenne L.)

采用盆栽方法模拟不同镉污染状况,研究接种丛枝菌根真菌(AM)Glomus intraradices对黑麦草生长和富集、运转镉的影响。结果表明,土壤镉水平增加明显提高了黑麦草菌根侵染率,而显著降低了黑麦草的生长量,但对磷浓度无显著影响,表明Glomus intraradices对镉胁迫具有一定的耐性,并对黑麦草的磷营养和生长未表现出促进作用。Glomus intraradices的存在明显促进了黑麦草对镉的富集,菌根形成强化镉在根系的固持作用,减少镉向地上部运转,进而降低黑麦草地上部的镉浓度,减轻了镉对地上部的毒害,表现在根富集系数均大于1,运转系数远远小于1。这一结果对镉污染农田修复以及草坪草和牧草品质的改善都有重要意义。

To investigate the possible role of arbuscular mycorrhizal（AM） on the bioremediation of Cd contaminated soils,pot experiments were conducted to adopt simulating contaminations on sandyloam soil.Effect of arbuscular mycorrhizal（Glomus intraradices） on plant growth and Cd enrichment and translocation were determined at three Cd application levels（0,15,45 mg/kg）.Cd in soil significantly increased the infection rate of ryegrass by G.intraradices while decreased dry weight of ryegrass.P concentration of ryegrass plant was not significantly affected by inoculation of AM fungi.These results implied that G.intraradices had some endurance to Cd contamination in soil,while no promotion on P uptake and the growth of ryegrass.Cd enrichment in ryegrass was stimulated by inoculation with G.intraradices.AM fungi strengthened the bio-fixing of Cd in root and reduced Cd translocation from root to shoot,thus decreased Cd concentration in shoot,which were explained by the fact that the enrichment coefficient of Cd in root was above 1 while the translocation coefficient was below 1.AM fungus could adjust the distribution proportion of Cd in host plant and protect host plants against heavy metal contamination.These functional characters of AM fungi could play a great role in remediation of Cd contaminated farmland and improving the quality of turf and forage grasses.