光照条件对丛枝菌根真菌吸收外源氮产精氨酸的影响

以高粱（Sorghum bicolor L．Moench）为宿主植物，接种丛枝菌根（arbuscular mycorrhiza，AM）真菌Glomus intraradices，采用三室隔离培养盒，在菌丝室加浓度为4mmol／L的精氨酸（Arg）、谷氨酰胺（Gln）、尿素（Urea）和NH4NO3，分别在4800，13200和17600lx光照条件下培养，通过测定根外菌丝和菌根中精氨酸的含量，探究了光照条件对丛枝菌根真菌吸收不同外源氮产生精氨酸的影响．结果表明：不同光照条件下不同外源氮对根外菌丝和菌根中精氨酸含量的影响不同，4800lx光照下添加谷氨酰胺和17600lx光照下添加NH4NO3，根外菌丝和菌根中的精氨酸含量均高于同光照条件下其他外源氮处理；13200lx光照下，不同外源氮对根外菌丝中精氨酸含量的影响大小为Arg〉Gln〉Urea〉NH4NO3，对菌根中精氨酸含量的影响为Gln〉Arg〉Urea〉NH4NO3．强光照可以促进丛枝菌根真菌孢子量、根侵染和菌丝量的提高．在相同氮源处理下，光照强度的影响表现为17600lx〉13200lx〉4800lx．

Effects of different lights intensity on the assimilation of different forms of nitrogen and production of arginine by arbuscular mycorrhizal fungus

Arbuscular mycorrhizal （ AM ） fungus （Glomus intraradices ） was associated with the host plant （ Sorghum bicolor L. Moench ） and grown in three-part pot culture system, with addition of 4 mmol/L different forms of exogenous nitrogen into the mycelium compartment, effects of different illumination intensity on the assimilation of different nitrogen and production of arginine by arbuscular mycorrhizal fungus were examined by measuring arginine contents of the extraradical mycelium （ERM） and mycorrhizal roots. The results showed that the effects of different nitrogen uptake and incorporation into arginine were different in 3 levels of illumina- tion intensity. When Gln was the exogenous nitrogen in 4 800 lx and NH4NO3 was the exogenous nitrogen in 17 600 lx, the arginine concentration in the extraradical mycelium and mycorrhizal roots was higher than other exogenous nitrogen. In 13 200 lx the capability of arginine formation in ERM was ranked in order of Arg 〉 Gln 〉 Urea 〉 NH4NO3 and in mycorrhizal roots it was Gln 〉 Arg 〉 Urea 〉 NH4NO3. Dry weight of ERM, spores a- mount and mot infection were improved in high light intensity, viz. 17 600 lx 〉 13 200 lx 〉4 800 lx.