丛枝菌根真菌与重金属的相互作用对玉米根际微生物数量和磷酸酶活性的影响

以玉米为供试植物 ,研究了砂培条件下不同丛枝菌根真菌 (Acaulosporalaevis,Glomuscaledonium ,Glomusmanihotis)与不同浓度重金属 (铜和镉 )的相互作用对菌根侵染率、孢子数、根际微生物数量和磷酸酶活性的影响 .在不同浓度的铜和镉中 ,G .caledonium的侵染率均最高 ,且随重金属浓度的增加而变化较小 ,而它的孢子数在这 3种接种处理中最低 .低量的铜 (0 .0 5mg/kg)可显著地减少不接种、接种A .laevis和G .manihotis的细菌数量 ,却能显著地增加接种处理的真菌数量 .当溶液中铜的浓度大于 0 .2mg/kg时 ,接种处理的真菌数量小于不接种处理的真菌数量 .铜或镉的浓度不同时放线菌数量均有接种远大于不接种 ,其中接种之间放线菌数量相差不大 ,且随重金属浓度增大而变化较小 .无论是不同浓度的铜还是不同浓度的镉的接种处理常有利于增加磷酸酶活性 .重金属浓度低时 ,细菌和真菌数量、磷酸酶活性变化较大 ,高浓度时变化较小 .图 7参 15

EFFECT OF INTERACTIONS BETWEEN ARBUSCULAR MYCORRHIZAL FUNGI AND HEAVY METALS ON MICROBIAL POPULATIONS AND PHOSPHATASE ACTIVITIES IN THE MAIZE RHIZOSPHERE

A sand culture experiment was designed to investigate the effect of interactions between arbuscular mycorrhizal fungi ( Acaulospora laevis , Glomus caledonium , G. manihotis ) and heavy metals (Cu and Cd) on mycorrhizal infection, spores, microbial populations and phosphatase activities. Under different Cu and Cd concentrations mycorrhizal the infection rate of G. caledonium was the highest among the three fungi and did not decrease with the increase of heavy metals concentrations, but, its spores were the fewest. Low Cu concentration (0.05 mg/kg) significantly decreased noninoculation of A. laevis and G. manihotis , but significantly increased inoculation of fungal population. When Cu concentration was higher than 0.2 mg/kg, the fungal populations of inoculation were lower than those of noninoculation. Actinomycete populations of inoculation were higher than those of noninoculation under various Cu and Cd concentrations, and actinomycete populations almost did not change with the increase of Cu and Cd concentration, and the differences among inoculations were not clear. Phosphatase activities of inoculation are usually higher than those of noninoculation. Bacterial and fungal populations and phosphatase activities greatly varied under low Cu and Cd concentrations, but changed only a little under high Cu and Cd concentrations. Fig 7, Ref 15