4株外生菌根真菌对Al3+吸收与吸附的研究

本研究采用液体培养方法,分析了4株源自不同生境的外生菌根真菌Pisolithus tinctorius(Pt 715)、Suillus luteus(Sl 08和Sl 14)、Gyroporus cyanescens(Gc 99)]细胞对铝的吸收与吸附,旨在探讨外生菌根真菌抗铝的机制,为减轻树木铝害、指导抗(耐)铝菌株的筛选和保持森林健康奠定理论基础.结果表明,Al3+对菌株Pt 715和Sl 08生长的影响不明显,但是可明显抑制Sl 14和Gc 99的生长;各供试菌株铝的吸附和吸收量均随培养液中Al3+浓度的升高而增加,可见环境中Al3+浓度是影响菌根真菌铝吸收量的关键因素;耐铝菌株(Pt 715和Sl 08)吸收的总铝及单位菌丝吸收的铝量较铝敏感菌株(Gc 99和Sl14)少,这可能是其对铝不敏感的原因之一.此外,增加对氮、磷、钾等营养元素的吸收亦可能是外生菌根真菌缓解铝毒的重要途径.

Al3+ Absorption and Assimilation by Four Ectomycorrhizal Fungi

The present experiment was carried out in order to know the resistance mechanism of the ectomycorrhizal (ECM) fungi under Al stress, to establish the theoretical foundation to alleviate the Al toxicity of trees, to guide the selection of Al-resisted ECM fungi and preserve forest health. The absorption and assimilation of Al³⁺ by four ECM fungi Pisolithus tinctorius (Pt 715), Suillus luteus (Sl 08 and Sl 14), Gyroporus cyanescens (Gc 99)], which were isolated from different forest soils, were investigated in pure culture in liquid media. The growths of Pt 715 and Sl 08 were less affected by Al³⁺, but growths of Sl 14 and Gc 99 were obviously inhibited by Al³⁺. With the increasing of Al³⁺concentration in culture, the absorption and assimilation of Al³⁺by four ECM fungi increased. It indicated that the concentration of Al³⁺ in environments might be the primary factor determining the Al³⁺content in the cell of each tested fungi. Amounts of Al³⁺ absorbed (in total or calculated in unit hyphae) by the Al³⁺ tolerant strains (Pt 715 and Sl 08) were significantly lower than those by the Al³⁺ sensitive strains (Sl 14 and Gc 99), which illustrated that reducing the absorption of Al³⁺ under Al³⁺ stress environment might be an effective approach to alleviate the Al³⁺ poison for these Al³⁺ tolerant strains. Furthermore, Al³⁺ stress could stimulate the ECM fungi to assimilate more N, P, and K, which might indicate that increasing requirement of the nutrients also could be helpful for ECM fungi to fight against the harmful effects caused by Al³⁺stress.