Inhibition of endogenous urease activity by NBPT application reveals differential N metabolism responses to ammonium or nitrate nutrition in pea plants: a physiological study
Inhibition of endogenous urease activity by NBPT application reveals differential N metabolism responses to ammonium or nitrate nutrition in pea plants: a physiological study
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DOI：
10.1007/s11104-013-1830-x
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发表时间：
2013-12-01
期刊：
影响因子：
4.9
通讯作者：
Ariz, I.
中科院分区：
文献类型：
--
作者：
Cruchaga, S.;Lasa, B.;Ariz, I.
尿素是作物氮肥的主要形态，但也是植物自身重要的氮素代谢产物。因此，对植物体内尿素代谢的了解可能对后续的氮肥管理有很大的帮助。目前看来，精氨酸酶是体内唯一能产生尿素的植物酶。因此，这项工作的目的是更深入地了解内源尿素酶活性抑制的意义及其在氮代谢中的作用，这取决于所提供的氮源。在存在或不存在尿素酶抑制剂NBPT的情况下，以铵或硝酸盐作为唯一的氮源种植油豆)植株。当供应NBPT时，NBPT被植物吸收并从根转移到叶片，在那里它降低了内源尿素酶的活性。氮同化酶和含氮化合物对氮素代谢的不同反应表明，氨态氮和硝态氮胁迫下植物体内精氨酸分解代谢的激活程度不同，氨态氮胁迫下植物体内的精氨酸分解代谢比硝态氮胁迫下更高，这可能是由于在氮素代谢和开花衰老过程中，在氮素循环和再动员过程中起关键作用的酶的底物周转率较高。
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.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.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.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.