Effect of nitrate on nitrogen fixation and nitrate assimilation in Azorhizobium-Sesbania rostrata symbiotic system
Raju, K.S.; Sharma, N.D.; Lodha, M.L.
Indian Journal of Experimental Biology 35(8): 871-875
1997
ISSN/ISBN: 0019-5189 PMID: 9475064 Document Number: 480536
Root nodule formation was inhibited by 30% and 50% respectively at low concentration of 1 mM and 2 mM nitrate, while stem nodule formation was enhanced by 50% only at 1 mM nitrate. The nodule specific nitrogenase activity decreased with the increasing concentration of nitrate. At 1 mM nitrate nitrogenase activity per plant stem nodule was not affected, but it was less than 50% in the root nodules as compared to control. Increasing concentration of nitrate increased in vivo activity of nitrate reductase (NR) significantly in stem, root nodules and leaves. Nodule cytosolic NR utilized both NADH and succinate as electron donor, but not reduced MV. However bacteroidal NR utilized reduced MV as reductant more efficiently than succinate.