氮源对杜鹃花菌根真菌氮吸收及硝酸还原酶活性的影响

采用菌丝干重法、半微量凯氏定氮法和磺胺比色法分别测定了HD19、ZT13和D1 3个树粉孢属杜鹃花菌根真菌菌株在铵态氮、硝态氮和有机氮培养基中的生物量、含氮量和硝酸还原酶活性。结果表明:3个菌株在3种氮源培养基中生长良好,而且无机氮培养基中菌株生物量和氮吸收量均显著高于有机氮培养基; 其中菌株HD19在硝态氮培养基中氮吸收量显著高于铵态氮,而菌株ZT13和D1在铵态氮培养基中氮吸收量较高; 菌株在硝态氮培养基中硝酸还原酶活性均较高,说明树粉孢属杜鹃花菌根真菌不仅具有较好的利用硝态氮的能力,还可以吸收利用其他形态的氮源,外源硝态氮可以诱导该类真菌硝酸还原酶活性的提高。

Effects of different nitrogen sources on the nitrogen uptake and nitrate reductase activities of ericoid mycorrhizal fungi

In order to analyse the effects of nitrogen on the nitrogen uptake and nitrate reductase activities of ericoid mycorrhizal fungus, this study determined the mycelial biomass, nitrogen uptake and nitrate reductase activities of three strains of Oidiodendron sp.cultured on ammonium, nitrate and organic nitrogen medium respectively. The results showed that the three strains grew well in different nitrogen source medium, and the strain biomass and nitrogen uptake in inorganic nitrogen medium were significantly higher than that in organic nitrogen medium. The nitrogen uptake by HD19 in nitrate nitrogen medium was significantly greater than that in ammonium nitrogen medium, while the strain ZT13 and D1 had the opposite result. Nitrate reductase activities of the two strains were higher in nitrate nitrogen medium than other nitrogen source. This illustrated that the ericoid mycorrhizal fungi(Oidiodendron sp.)had the ability to utilize different nitrogen source. In all these nitrogen, the nitrate was a good one for ERM fungi growth,and it can also induce nitrate reductase activities of the ERM fungi.