biologia plantarum

Biologia plantarum 60:190-194, 2016 | DOI: 10.1007/s10535-015-0556-4

Metabolic regulation of ammonia emission in different senescence phenotypes of Nicotiana tabacum

Y. J. Wu¹, T. Z. Yang^1,*, Y. Y. Song¹, X. Q. Zhang¹, S. X. Xu¹, G. Xue¹, X. X. Xing¹

¹ Henan Agricultural University, Zhengzhou, P.R. China

In order to reveal the character of ammonia emission in senescent tobacco (Nicotiana tabacum), the content of NH₄ ⁺, total nitrogen, and soluble protein, and the activities of nitrogen metabolism-related enzymes were measured in leaves of a quick-leaf-senescence phenotype ZY90 and a slow-leaf-senescence phenotype NC89. Compared with NC89, ZY90 had a higher NH₄ ⁺ accumulation, a lower glutamine synthetase activity, and a significantly higher stomatal ammonia compensation point, and ammonia emission during 40 to 60 d after leaf emergence. During senescence, the quick-leafsenescence phenotype was characterized by nitrogen re-transfer by ammonia emmission, whereas the slow-leafsenescence phenotype by nitrogen re-assimilation. The ammonia emission was primarily regulated by glutamine synthetase activity, apoplastic pH, and NH₄ ⁺ content.

Keywords: nitrogen metabolism; stomatal ammonia compensation point; tobacco

Subjects: ammonium; emission; senescence; nitrogen metabolism; glutamine synthetase; glutamate dehydrogenase; tobacco

Received: March 12, 2015; Revised: July 12, 2015; Accepted: July 17, 2015; Published: January 1, 2016  Show citation