外源氮处理对丛枝菌根真菌—根瘤菌产精氨酸的影响

Effects of exogenous nitrogen on the production of arginine by arbuscular mycorrhizal fungus-rhizobium

以绿豆(Phaseolus radiatus L.,绿宝六号)为宿主植物,采用三室隔离盆栽培养系统,接种丛枝菌根(arbuscular mycorrhiza,AM)真菌、根瘤菌及AM真菌和根瘤菌双接种,研究豆科植物接种AM真菌吸收外源氮产精氨酸的影响,外源氮分别为4 mmol·L-1NH4Cl,4 mmol·L-1NH4NO3,4 mmol·L-1尿素(Urea)和4 mmol·L-1精氨酸(Arginine,Arg)。结果表明,不同接种处理下不同外源氮对菌根中精氨酸含量影响不同,单接AM真菌及双接种均在施加外源氮Arg时精氨酸含量最高,分别为2.47和3.20 mg·g-1,且双接种明显高于单接AM真菌处理,而单接根瘤菌处理中精氨酸含量变化不明显。与单接种相比,双接种下菌根侵染率、根瘤数、根瘤鲜重及茎叶中总氮含量都有所提高,且在施加NH4NO3时效果最好。由此得出,AM真菌和根瘤菌双接种更利于植物氮源的吸收及生长。

In order to study the influence of exogenous nitrogen on the production of arginine generated by arbuscular mycorrhizal（AM） fungi in leguminous plants,a pot culture experiment was carried out. Phaseolus radiatus L. was used as the host plant with inoculation of AM fungi and /or rhizobium. Exogenous nitrogen including 4 mmol·L^-1 NH4 Cl,4 mmol·L^-1 NH4NO3,4 mmol·L^-1 urea and 4 mmol·L^-1 Arg were adopted in this pot experiment. It was shown that the arginine concentration in the mycorrhizal roots was highest,when Arg was supplied with AM fungi or double inoculation,which was 2. 47 and 3. 20 mg·g^-1,respectively,and the latter was significantly higher than the former. But,arginine production was not influenced with rhizobium inoculation. With double inoculation,the mycorrhizal infection rate,chlorophyll content,nodule number and weight and the total uptake of nitrogen were significantly increased compared with AM fungi inoculation. And,the effects of NH4NO3 were the best among all kinds of tested exogenous nitrogen. It was concluded that the double inoculation was more beneficial for the absorption of nitrogen and growth of plants.