锰离子胁迫下外生菌根真菌对土壤钾释放的影响  

Dissolution and release of soil potassium by ectomycorrhizal fungi under Mn^2+ stress

作　　者：张亮 李玉婷 许晓风 ZHANG Liang;LI Yuting;XU Xiaofeng(School of Chemistry and Bioengineering,Nanjing Normal University Taizhou College,Taizhou 225300,China;School of Life Sciences,Nanjing Normal University,Nanjing 210023,China)

机构地区：[1]南京师范大学泰州学院化学与生物工程学院,江苏泰州225300 [2]南京师范大学生命科学学院,江苏南京210023

出　　处：《浙江农业学报》2020年第7期1215-1222,共8页Acta Agriculturae Zhejiangensis

基　　金：江苏省高等学校自然科学基金(16KJB180017);江苏省高校实验室研究会课题(GS2019YB06)。

摘　　要：外生菌根真菌作为森林生态系统的组成部分,参与植物的养分吸收和利用。试验以彩色豆马勃(Pisolithus tinctorius,Pt)和松乳菇(Lactarius deliciosus,Ld)作为供试菌株,以土壤作为培养基唯一钾源,采用液体培养的方法,研究不同锰离子质量浓度下2株供试菌株活化土壤难溶性钾的能力与机理。结果显示,2株外生菌根真菌的生物量随锰离子质量浓度升高而减低,生长受到显著(P<0.05)抑制。在相同锰离子质量浓度下,菌株Pt的菌丝生物量均大于Ld,说明Pt的抗锰能力强于Ld。2株外生菌根真菌均分泌草酸和乙酸,培养基中的pH下降。同时,2株外生菌根真菌均能降低土壤中矿物结构钾的含量,并增加土壤中交换性钾含量,说明在锰离子胁迫下,外生菌根真菌能活化土壤中的难溶性钾。相关分析表明,培养液中草酸分泌量与土壤交换性钾含量呈极显著(P<0.01)正相关,与土壤矿物结构钾含量呈显著(P<0.05)负相关,培养基中的pH与土壤中交换性钾含量呈极显著(P<0.01)负相关。推测外生菌根真菌分泌的有机酸和氢离子有利于土壤难溶性钾的活化,其中草酸可能起到关键作用。由于有机酸和氢离子的分泌量不同,2株外生菌根真菌对土壤难溶性钾的活化能力存在差异。Ectomycorrhizal fungi(ECMF),important components in forest ecosystems,could participate in nutrient absorption and utilization.Pisolithus tinctorius(Pt)and Lactarius deliciosus(Ld)were cultured in liquid Pachlewsk medium with soil as the potassium(K)source under Mn 2+stress,to study the ability and mechanism of two strains to activate insoluble K.The results showed that the biomass of two strains decreased with the increase of Mn 2+,and the growth was significantly(P<0.05)inhibited.The biomass of Pt was higher than Ld under all Mn 2+concentrations,indicating that the resistance to manganese toxicity of Pt was stronger than Ld.Oxalic acid and acetic acid were detected in the medium of ECMF.Two strains reduced mineral K,and increased exchangeable K in soil,indicating that the ECMF could activate the insoluble K in soil under Mn 2+stress.Correlation analysis showed that oxalic acid secretion was significantly(P<0.01)positively related to soil exchangeable K,and was significantly(P<0.05)negatively related to soil mineral K.Meantime,the pH in culture medium was significantly(P<0.01)negatively related to exchangeable K in soil.Therefore,the organic acids and hydrogen ions secreted by ECMF were beneficial to the activation of soil insoluble K,in which oxalic acid might play a key role.Due to the different secretion capacity of organic acids and hydrogen ions,the activation abilities of the two ECMF strains were different.

关 键 词：锰离子 外生菌根真菌 黄红壤 钾 

分 类 号：S153.1[农业科学—土壤学] S718.81[农业科学—农业基础科学]