BACKGROUND AND AIMS: Increased levels of nitrogen (N) deposition lead to enhanced N contents and reduced productivity of many bryophyte species. This study aimed at elucidating the mechanisms by which enhanced N uptake may cause growth reduction of bryophytes, focusing on the effects of N addition on carbon (C) metabolism of bryophytes. METHODS: Plantlets of Thuidium tamariscinum and Hylocomium splendens were fertilized with NH(4)NO(3) (N load equalling 30 kg ha(-1) year(-1)) for 80 d, including a pulse labelling experiment with (13)CO(2) to dissect the partitioning of carbon in response to N addition. KEY RESULTS: Growth of T. tamariscinum was not affected by N addition, while H. splendens showed a trend towards growth reduction. Total N concentration was significantly increased by N addition in H. splendens, a significant increase in amino acid-N was found in T. tamariscinum only. In both bryophyte species, a reduction in concentration of lipids, the greatest C storage pool, as well as markedly enhanced turnover rates of C storage pools in fertilized plants were observed. CONCLUSIONS: The results suggest that growth reduction of H. splendens under high levels of N deposition may be caused by enhanced synthesis of N-containing organic compounds, most probably of cell wall proteins. Disturbance of cellular C metabolism, as indicated by enhanced C pool turnover, may further contribute to the decline in productivity of H. splendens.
BACKGROUND AND AIMS: Increased levels of nitrogen (N) deposition lead to enhanced N contents and reduced productivity of many bryophyte species. This study aimed at elucidating the mechanisms by which enhanced N uptake may cause growth reduction of bryophytes, focusing on the effects of N addition on carbon (C) metabolism of bryophytes. METHODS: Plantlets of Thuidium tamariscinum and Hylocomium splendens were fertilized with NH(4)NO(3) (N load equalling 30 kg ha(-1) year(-1)) for 80 d, including a pulse labelling experiment with (13)CO(2) to dissect the partitioning of carbon in response to N addition. KEY RESULTS: Growth of T. tamariscinum was not affected by N addition, while H. splendens showed a trend towards growth reduction. Total N concentration was significantly increased by N addition in H. splendens, a significant increase in amino acid-N was found in T. tamariscinum only. In both bryophyte species, a reduction in concentration of lipids, the greatest C storage pool, as well as markedly enhanced turnover rates of C storage pools in fertilized plants were observed. CONCLUSIONS: The results suggest that growth reduction of H. splendens under high levels of N deposition may be caused by enhanced synthesis of N-containing organic compounds, most probably of cell wall proteins. Disturbance of cellular C metabolism, as indicated by enhanced C pool turnover, may further contribute to the decline in productivity of H. splendens.
Authors: Erin E Shortlidge; Sarah M Eppley; Hans Kohler; Todd N Rosenstiel; Gustavo E Zúñiga; Angélica Casanova-Katny Journal: Ann Bot Date: 2016-10-29 Impact factor: 4.357
Authors: Gustaf Granath; Joachim Strengbom; Angela Breeuwer; Monique M P D Heijmans; Frank Berendse; Håkan Rydin Journal: Oecologia Date: 2009-01-09 Impact factor: 3.225
Authors: Michal Hejcman; Jirina Száková; Jürgen Schellberg; Petr Srek; Pavel Tlustos; Jirí Balík Journal: Environ Monit Assess Date: 2009-06-20 Impact factor: 2.513