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Effect of nitrogen supply on the C/N balance in the lichen Evernia prunastri (L.) Ach

This study investigated the relationship between nitrogen and carbon in the thalli of the lichen Evernia prunastri, with an emphasis on the role of the C/N balance in the response of this species to N excess. | Turkish Journal of Biology Turk J Biol (2013) 37: 165-170 © TÜBİTAK doi:10.3906/biy-1205-4 http://journals.tubitak.gov.tr/biology/ Research Article Effect of nitrogen supply on the C/N balance in the lichen Evernia prunastri (L.) Ach. 1,2, 2 2,3 2 2 Silvana MUNZI *, Tommaso PISANI , Luca PAOLI , Monia RENZI , Stefano LOPPI University of Lisbon, Center for Environmental Biology, Campo Grande, Bloco C2, 1749-016 Lisbon, Portugal 2 Department of Environmental Science, University of Siena, via P.A. Mattioli 4, I-53100 Siena, Italy 3 Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, 845 23 Bratislava, Slovakia 1 Received: 02.05.2012 Accepted: 03.09.2012 Published Online: 25.03.2013 Printed: 25.04.2013 Abstract: This study investigated the relationship between nitrogen and carbon in the thalli of the lichen Evernia prunastri, with an emphasis on the role of the C/N balance in the response of this species to N excess. For this purpose, thalli collected at a remote site were sprayed for 5 weeks with NH4NO3 (0.05 and 1 M) and (NH4)2SO4 (0.025 and 0.5 M) solutions, and later analyzed for their C and N content. The results showed that the total N content of thalli increased and the total C content decreased along with increasing N concentration in the treatment solutions. Consequently, the C/N ratio also significantly decreased in treated samples. The Fv/Fm ratio, taken as a vitality index, turned out to be positively correlated with C content and negatively correlated with N content. It is suggested that N stress is caused by the lack of compensation for elevated ammonium levels with higher C assimilation. It is concluded that E. prunastri is a suitable bioindicator of N pollution and that the C/N ratio deserves further investigation as a promising tool for early warning of N excess. Key words: Ammonium, biomonitoring, fertilization, physiological parameters, symbiosis 1. Introduction The ecological success of symbiotic forms of life is .