Cruchaga, S. and Lasa, B. and Jauregui, I. and González-murua, C. and Aparicio-tejo, P. M. and Ariz, I. (2013) Inhibition of endogenous urease activity by NBPT application reveals differential N metabolism responses to ammonium or nitrate nutrition in pea plants : a physiological study. Plant and Soil, 373 (1-2). pp. 813-827. ISSN 0032-079X
Full text not available from this repository.Abstract
Background and aims Urea is the predominant form of N applied as fertilizer to crops, but it is also a significant N metabolite of plants themselves. As such, an understanding of urea metabolism in plants may contribute significantly to subsequent N fertilizer management. It currently appears that arginase is the only plant enzyme that can generate urea in vivo. The aim of this work was, therefore, to gain a more in-depth understanding of the significance of the inhibition of endogenous urease activity and its role in N metabolism depending on the N source supplied. Methods Pea (Pisum sativum cv. Snap-pea) plants were grown with either ammonium or nitrate as the sole N source in the presence or absence of the urease inhibitor NBPT. Results When supplied, NBPT is absorbed by plants and translocated from the roots to the leaves, where it reduces endogenous urease activity. Different N metabolic responses in terms of N-assimilatory enzymes and N-containing compounds indicate a different degree of arginine catabolism activation in ammonium- and nitrate-fed plants. Conclusions The arginine catabolism is more highly activated in ammonium-fed plants than in nitrate-fed plants, probably due to the higher turnover of substrates by enzymes playing a key role in N recycling and remobilization during catabolism and in early flowering and senescence processes, usually observed under ammonium nutrition.