外生菌根真菌吸收汞的动力学

KINETICS OF HG^(++) ABSORPTION BY ECTOMYCORRHIZAL FUNGI

液体培养外生菌根真菌彩色豆马勃(Pisolithus tinctorius XC1和Pisolithus tinctorius 270)和土生空团菌(Cenocuccum geophinum SIV)三周,菌丝体的阳离子交换量差异显著,但与二价汞(Hg++)的吸收和吸附关系不大。进入菌丝体的Hg++大部分被细胞吸收,少部分吸附于胞外。三种外生菌根真菌吸收Hg++的Cmin很低,变化于0.28～0.45mmol/ L,说明外界溶液中只要存在低浓度的Hg++,外生菌根真菌就能吸收。外生菌根真菌吸收Hg++的Imax和Km值Cg SIV > Pt XC1 Pt 270,由于Hg++在外生菌根真菌的菌丝中不易传递,推测Cg SIV形成外生菌根之后,寄主植物能适应高Hg++环境,Cg SIV形成的菌根化林木种苗可用于汞污染矿墟和土壤上的植树造林,修复汞污染的生态环境。

Ectomycorrhizal fungi Pt CX1, Pt 270 and Cg siv were cultured in Pachlewski liquid medium for 3 weeks to investigate Hg++ absorption. There were significant differences in cation exchange capacity among the fungi, but no relationship with Hg++ absorption and adsorption by ectomycorrhizal fungi. Hg++ moved into hyphae presented mainly in cells and little in cell spaces if any. Lower Cmin values were detected for Hg++ absorption by the three fungi, ranged from 0.28 to 0.45 mmol L-1. This result indicates Hg++ accumulation by the fungi in conditions present Hg++ at very low concentrations. Imax and Km for fungal Hg++ absorption were in accordance with Cg Siv > Pt CX1 Pt270, suggesting the trees mycorrhized by Cg siv could adapt in Hg polluted soils and Hg mine residues.