丛枝菌根根外菌丝对不同形态氮素的吸收能力

UPTAKE OF DIFFERENT FORMS OF NITROGEN BY HYPHAE OF ARBUSCULAR MYCORRHIZAL FUNGI

本试验以玉米为宿主植物，以Glomus mosseae和Glomus intraradices为接种剂，采用空气隔板分室-半液培系统，在植株收获前48h向菌丝室供应15^N标记的不同形态氮素，探讨丛枝菌根根外菌丝吸收传递不同形态氮素的能力。结果表明，丛枝菌根根外菌丝吸收传递15^N能力因菌种和氮素形态而异。丛枝菌根真菌G．intraradices吸收传递15^N的能力高于G．mossea，根外菌丝吸收传递不同形态15^N的能力为15^NH4^＋N-Gln〉15^N-Gly〉15^NO3^-。根外菌丝吸收传递的15^N对植株氮营养的贡献仅为0．004％～0.032％．

A two-compartment incorporating air-gap device and 15 ^N-labeling technique was used to investigate the uptake of different forms of N by arbuscular mycorrhizal fungi（AMF）. Maize （ Zea mays L. ） was in association with Glomus mosseae, or Glomus intraradices. Solutions labeled with different forms of 15^N were supplied to the hyphae compartment 48 h before harvesting. The result showed that the uptake capability of 15^N varied with fungi species and N forms supplied. Percentage of 15^ N taken Up over 48 h by G. intraradices was higher than that by G. mosseae. The uptake capability of 15 ^N by AMF was in the order of 15 NH4^＋ 〉 15 ^N-Gln 〉 15^ N-Gly 〉 15^ NO3^-. 15 ^N uptake by AMF hyphae accounted for 0. 004 % - 0. 032 % of total N uptake