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盆栽试验研究了不同培养条件(土壤与河沙)下,3种施Cd水平(0、5、50 mg kg-1)对菌根玉米生长、根系侵染率及重金属Cd吸收的影响。结果表明:施Cd水平显著影响玉米吸Cd能力。随Cd浓度增加,各处理根系与地上部分Cd浓度和吸收量显著增加,各施Cd水平下玉米根系Cd浓度和吸收量远远高于地上部分。不同培养条件下,各处理也表现出明显的差异。以河沙为培养基质,接种菌根真菌显著增加玉米的生物量及根系侵染率;在高Cd水平下,接种处理玉米根系中的Cd浓度和吸收量较对照显著增加,但地上部分的Cd浓度和吸收量却相应降低。以土壤为培养基质,随施Cd水平提高,植株吸Cd量增加,但接种处理植株根部与地上部Cd浓度均显著低于对照。试验表明,丛枝菌根真菌Glomus mosseae可减少重金属Cd向玉米植株地上部的运输,将更多的Cd固持在菌根之中,这可能是菌根减轻宿主植物Cd毒害的一个重要机制。
Pot experiment was conducted to study the effects of three Cd application rates (0, 5 and 50 mg kg-1) on mycorrhizal corn growth, root infection rate and heavy metal Cd uptake under different culture conditions (soil and river sand). The results showed that Cd application significantly affected Cd uptake by maize. With the increase of Cd concentration, Cd concentration and uptake of root and shoot increased significantly in all treatments, and the Cd concentration and uptake of maize roots under Cd application were much higher than aboveground parts. Under different culture conditions, the treatments also showed obvious differences. In river sand culture medium, inoculation of mycorrhizal fungi significantly increased the biomass and root infection rate of maize. At high Cd levels, Cd concentration and uptake in maize roots significantly increased compared with the control, but Cd Concentration and absorption are reduced accordingly. With soil as the substrate, Cd uptake increased with the application of Cd, but Cd concentrations in roots and shoots of inoculated plants were significantly lower than those in the control. Experiments show that the arbuscular mycorrhizal fungi Glomus mosseae can reduce the transport of heavy metal Cd to the shoots of maize plants and more Cd can be retained in the mycorrhiza, which may be an important mechanism by which the mycorrhiza can reduce Cd toxicity of the host plants.