Arbuscular mycorrhiza confers lead tolerance and uptake in Miscanthus sacchariflorus

The effects of an arbuscular mycorrhizal fungi (AMF) association on the growth, survival capabilities, nutrients and lead (Pb) uptake of Miscanthus sacchariflorus under different Pb concentrations were studied in the form of pot cultures. The treatments comprised inoculation or non-inoculation of the AMF, Gigaspora margarita, and the addition of three Pb concentrations to the soil (0, 100 and 1000?mg?kg^?1). The addition of Pb significantly decreased mycorrhizal colonisation. The inoculation of AMF with Pb increased chlorophyll content, Fv/Fm, total dry mass, indole-3-acetic acid (IAA), total nitrogen, and total phosphorus, whereas H₂O₂ level, indole-3-acetic acid oxidase (IAAO) activity, and peroxidase (POD) activity were low compared to those in the non-inoculated treatments. Moreover, the application of AMF together with Pb doses induces concentrations of Pb in the plant, where the higher dose of Pb (1000?mg?kg^?1) induces a lower content of Pb in the aerial part of the plant but a higher content in the root. G. margarita enhanced the tolerance of M. sacchariflorus against Pb toxicity, and facilitated the accumulation of Pb in the plant roots, whereas translocation to the shoots was inhibited at the highest dose Pb (1000?mg?kg^?1). However, in contaminated soil, the Pb removal capability of M. sacchariflorus with AMF was remarkable.     

丛枝菌根真菌Gigaspora margarita孢子伴生菌群效应分析

丛枝菌根真菌的孢子表面存在与之伴生的微生物类群,其中以细菌为主．本文以不同处理方式的珍珠巨孢囊霉（Gigaspora margarita）孢予与白三叶草（nifolium repens L．）进行共培养试验．试验分为4组：A,孢子绎表面消毒;B,孢子表面消毒后并同接伴生菌;C,孢子未经表面消毒;D,孢子存在于土壤接种物中．以灭菌的蛭石为基质,修改的Hoagland营养液作为补充营养,在相对无杂菌的环境中培养3mo,并取样观察．结果表明,处理A的植株茎叶鲜（干）重显著低于其它处理,根系鲜重无显著差异．菌根侵染率以D处理最高,A与B、C之间存在不显著的差异．产孢数量以A最少,并与B、C之间存在显著性差异．以PCR-DGGE技术分析各处理之间孢子伴生细菌的种群差异．结果显示,A处理与其它处理间存存较大的差异,其它处理间差异较小．分析认为,伴生菌群对G．margarita及其宿主植物的生命活动起着直接或间接的影响．图1表3参26