丛枝菌根真菌菌丝体吸附重金属的潜力及特征

应用玻璃珠分室培养系统获得丛枝菌根真菌材料,研究了离体真菌菌丝体对pH缓冲体系中Zn、Cd和Mn等金属离子的吸附特征。试验结果表明,真菌菌丝体对各金属离子吸附能力差异显著,对Cd最强,Zn次之,Mn最弱。试验条件下,菌体可分别吸附相当于自身干物重1.6%的Mn、2.8%的Zn和13.3%的Cdo吸附于菌丝体的Cd2+绝大部分可以被Ca2+交换吸附。另外研究了宿主植物根系对Cd的吸附作用,证实菌根真菌侵染改变了根系的吸附特性,相对于非菌根根系,菌根的CEC较高,对Cd的吸附能力较强。试验结果为重金属污染条件下丛枝菌根强化根系的屏障作用提供了直接证据。

CHARACTERS OF METAL ADSORPTION BY AM FUNGAL MYCELIUM

Using fungal biomass recovered from compartmented glass bead cultivation system, Zn, Cd and Mn binding capacity of arbuscular mycorrhizal fungi were characterized in pH buffering solutions. Results indicated that fungal mycelium have significantly different binding capacity for different metals, the strongest is for Cd, followed by Zn, and the least for Mn. Under the current experimental conditions, the fungi could adsorb Mn, Zn and Cd up to 1.6%, 2.8% and 13.3% dry biomass respectively. However, most of the adsorbed Cd2+ could be exchanged by Ca2+. In addition, comparison on Cd adsorption by non-mycorrhizal and mycorrhizal roots demonstrated that mycorrhizal colonization changed adsorption characteristics of plant roots. Compared with non-mycorrhizal roots, mycorrhizal roots have higher CEC and stronger Cd binding capacity. Results from this study provided direct evidences for enhanced metal binding capacity of plant roots colonized by arbuscular mycorrhizal fungi.