磷对外生菌根真菌松乳菇和双色蜡蘑草酸、氢离子和磷酸酶分泌的影响

Effects of phosphorus on the excretion of oxalate, hydrion and phosphatase by ectomycorrhizal fungi Lactarius deliciosus and Laccaria bicolor

在液体培养基中设置无磷、低磷、中磷和高磷四种磷浓度,离体培养松乳菇Lactarius deliciosus的3个株系Ld-01、Ld-02、Ld-03和双色蜡蘑Laccaria bicolor S238N,分别测定外生菌根真菌的生长量、草酸、氢离子和酸性磷酸酶分泌速率。结果表明,在中磷的条件下,外生菌根真菌的生长最好,无磷、低磷或高磷对它们的生长产生抑制作用,抑制程度因菌种(株)不同而异。草酸、氢离子和酸性磷酸酶的分泌速率顺序为:无磷(0gNaH2PO4/L)>低磷(0.229gNaH2PO4/L)>中磷(1.147gNaH2PO4/L)>高磷(5.735gNaH2PO4/L),表现出明显的种(株)间差异,看来外源磷的供应状况可能有调节外生菌根真菌活化土壤无机磷和有机磷的作用。在缺磷和低磷条件下,外生菌根真菌具有较强的活化作用,在足磷的条件下活化作用减小,由此有效地利用土壤中的磷。

Ectomycorrhizal fungi Lactarius deliciosus strains Ld-01, Ld-02 and Ld-03 and Laccaria bicolor S238N were cultured in liquid mediums with or without phosphorus. The growth and the excretion of oxalate, hydrion and acid phosphatase were then investigated. The results showed the growth of ectomycorrhizal fungi was most vigorous under moderate concentration of H2PO4L （1.147g NaH2POdL） and inhabitation of growth occurred under the conditions of deficiency or excess of phosphorus. The excretion rate of oxalate, hydrion and acid phosphatase by the fungi depended on concentration of phosphorus and changed in sequence of no phosphorus （0g NaH2PO4/L） 〉 low phosphorus （0.229g NaH2PO4/L） 〉 moderate phosphorus （1.147g NaH2PO4/L） 〉 high phosphorus （5.735g NaH2PO4/L）. In the same phosphorus treatments the excretion rate varied with species and strains. It seems reasonable to suggest that the external supply of phosphorus might have an effect on regulation of ectomycorrhizal fungi in activating inorganic and organic phosphorus in soil. Under the condition of lacking phosphorus or low phosphorus mycorrhizal fungi have stronger activation in utilizing phosphorus in soil, while under the condition of rich phosphorus, such an activation decreases. Phosphorus in soil could be effectively utilized by ectomycorrhizal fungi in this way.