Publikationsdatum:
2012-02-18
Beschreibung:
Leaf gas-exchange, leaf and shoot anatomy, wood density and hydraulic conductivity were investigated in seedlings of Quercus suber L. grown for 15 months either at elevated (700 μmol mol −1 ) or normal (350 μmol mol −1 ) ambient atmospheric CO 2 concentrations. Plants were grown in greenhouses in a controlled environment: relative humidity 50% (±5), temperature similar to external temperature and natural light conditions. Plants were supplied with nutrients and two water regimes (WW, well watered; WS, water stress). After 6 months exposure to CO 2 enrichment an increase in photosynthetic rate, a decrease in stomatal conductance and a decrease in carbon isotope discrimination (Δ 13 C) were observed, along with enhanced growth and an increase in the number of branches and branch diameter. Over the same period, the shoot weight ratio increased, the root weight ratio decreased and the leaf weight ratio was unaffected. The specific leaf area increased due to an increase in total leaf thickness, mainly due to the palisade parenchyma and starch. However, after 9 and 15 months of elevated CO 2 exposure, the above-mentioned physiological and morphological parameters appeared to be unaffected. Elevated CO 2 did not promote changes in vessel lumen diameter, vessel frequency or wood density in stems grown in greenhouse conditions. As a consequence, xylem hydraulic efficiency remained unchanged. Likewise, xylem vulnerability to embolism was not modified by elevated CO 2 . In summary, elevated CO 2 had no positive effect on the ecophysiological parameters or growth of water stressed plants. Content Type Journal Article Category Original Paper Pages 1-13 DOI 10.1007/s00468-012-0691-x Authors M. Vaz, Departamento de Biologia, Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal H. Cochard, INRA, UMR 547 PIAF, 63100 Clermont-Ferrand, France L. Gazarini, Departamento de Biologia, Instituto de Ciências Agrárias e Ambientais Mediterrânicas (ICAAM), Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal J. Graça, Instituto Superior de Agronomia, Universidade Técnica de Lisboa, Tapada da Ajuda, 1349-017 Lisbon, Portugal M. M. Chaves, Instituto Superior de Agronomia, Universidade Técnica de Lisboa, Tapada da Ajuda, 1349-017 Lisbon, Portugal J. S. Pereira, Instituto Superior de Agronomia, Universidade Técnica de Lisboa, Tapada da Ajuda, 1349-017 Lisbon, Portugal Journal Trees - Structure and Function Online ISSN 1432-2285 Print ISSN 0931-1890
Print ISSN:
0931-1890
Digitale ISSN:
1432-2285
Thema:
Biologie
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Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
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