丛枝菌根根外菌丝对铵态氮和硝态氮吸收能力的比较

Uptake of ammonium and nitrate by external hyphae of arbuscular mycorrhizal fungi

采用空气隔板分室法并结合^(15)N标记技术,以玉米为宿主植物并接种Glomus mosseae和Glomus intraradices,比较了这两种真菌根外菌丝对铵态氮和硝态氮吸收传递能力的差异。结果表明,丛枝菌根根外菌丝吸收传递氮的能力因菌种和氮素形态而异。两种真菌根外菌丝吸收传递NH_4^+-N能力均高于NO_3^-N;G.intraradices根外菌丝吸收传递氮的能力高于G.mosseae,这可能与两种真菌根外菌丝生长量有关。

A two-compartment incorporating an air-gap device technique was used to compare the uptake of NH4^＋ -N or NO3^- -N by two Glomus isolates of arbuseular mycorrhizal fungi （AMF）. Maize （ Zea mays L. ） was inoculated with G. rnosseae, or G. intraradices or without. NH4^＋ -^15N or NO3^- -^15N was supplied to the hyphae compartment 48 h before harvesting. The N uptake capability of AMF varies with fungi species and N forms supplied. The uptake and translocation of NH4^＋ -N by AMF are higher than those of NO3^--N. N uptake capability by G. intraradices is higher than that of G. mosseae, and this may be related to the growth of external hyphae of the two fungi isolates in the substrate.