Changes in nitrate reductase and glutamine synthetase activities in Ziziphus mauritiana by different VAM fungi

Efficacy of different vesicular arbuscular mycorrhizae (VAM) species towards increasing nitrate reductase (NR) and glutamine synthetase (GS) activities in Ziziphus mauritiana was evaluated under glasshouse conditions. After 45 days of seedling growth, plant samples were analysed. In general GS activity was higher in all the treatments as compared to NR activity. Addition of VAM increased the activities of both these enzymes. However, different VAM species varied in their efficacy to increase these enzymatic activities. Among the five VAM species used during the present investigation, Glomus fasciculatum was found to be the most efficient VAM species for Z. mauritiana as it increased most effectively the activities of GS and NR in this multipurpose fruit tree of the Indian Thar desert. This VAM fungus also increased protein contents more than twofold in Z. mauritiana, which can be of great significance in producing highly proteinaceous leaf fodder of this desert plant.