不同外生菌根真菌对难溶性磷的活化

摘要

Nine species of ectomycorrhizal fungi were grown in liquid media to determine their ability to use rock phosphate as a sole source of phosphorus. The results showed that rock phosphate was solubilized by all 9 species of ectomycorrhizal fungi and significant difference existed among the 9 species in their solubility. Factors influencing the solubility included pH value and kinds and concentrations of organic acid excreted by ectomycorrhizal fungi. The decrease of pH increased the solubility but no correlation between the concentration of available phosphate and pH value was found. The excretion of organic acids of ectomycorrhizal fungi was closely related to the solubility of rock phosphate. Significant differences were found among species of ectomycorrhizal fungi in kinds and concentration of organic acid excreted. Oxalic acid, lactic acid, maleic acid and fumaric acid were detected from excretions of all nine ectomycorrhizal species.%研究了9种外生菌根真菌在纯培养条件下，对磷矿粉的活化利用情况。结果表明：不同菌根真菌对磷矿粉均有活化作用，且它们之间对磷矿粉的活化程度存在着很大差异性。影响菌根真菌对难溶性磷活化的主要因素包括菌液的酸度及有机酸的种类与含量。菌液中pH值的降低在一定程度上有利于难溶性磷的活化，但与有效磷含量无明显相关性。菌液中有机酸的分泌与难溶性磷的活化有密切关系，且分泌的有机酸的种类和含量因菌种不同而差异很大。9个菌种都可分泌草酸、乳酸、顺丁烯二酸和反丁烯二酸。