Trends in plant carbon concentration and plant demand for N throughout this century |
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Authors: | J Peñuelas Marc Estiarte |
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Institution: | (1) Centre de Recerca Ecològica i Aplicacions Forestals, Facultat de Ciències, Universitat Autònoma, 08193 Bellaterra, Barcelona, Spain, ES |
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Abstract: | Atmospheric CO2 concentration has increased by 25% over the preindustrial level. A parallel increase in C concentration and decreases in N
concentration and δ13C of plants grown throughout this century have been observed in plant specimens stored in herbaria. We tested our previous
results in a study of 12 more species collected in the western Mediterranean throughout this century (1920–1930, 1945–1955,
and 1985–1990) and tree rings of Quercus pubescens from the same area. These changes were accompanied by apparent increases in condensed tannin concentration. A decreasing trend
in δ15N both in herbarium material and tree rings was also found, indicating that ecosystems might cope with higher plant N demand
by decreasing N losses and increasing N fixation and mineralization. These results may contribute to a better understanding
of the effects of global change on carbon and nitrogen cycling.
Received: 12 November 1995 / Accepted: 17 May 1996 |
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Keywords: | Atmospheric CO2 concentration δ 15N δ 13C Herbarium specimens Nitrogen |
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