Effects of long-term elevated [CO2] from natural CO2 springs on Nardus stricta: photosynthesis, biochemistry, growth and phenology
1998
Cook, A.C. | Tissue, D.T. | Roberts, S.W. | Oechel, W.C.
Plants of Nardus stricta growing near a cold, naturally emitting CO2 spring in Iceland were used to investigate the long-term (> 100 years) effects of elevated [CO2] on photosynthesis, biochemistry, growth and phenology in a northern grassland ecosystem. Comparisons were made between plants growing in an atmosphere naturally enriched with CO2 (approximately 790 micromoles mol-1) near the CO2 spring and plants of the same species growing in adjacent areas exposed to ambient CO2 concentrations (approximately 360 micromoles mol-1). Nardus stricta growing near the spring exhibited earlier senescence and reductions in photosynthetic capacity (approximately 25%), Rubisco content (approximately 26%), Rubisco activity (approximately 40%), Rubisco activation state (approximately 23%), chlorophyll content (approximately 33%) and leaf area index (approximately 22%) compared with plants growing away from the spring. The potential positive effects of elevated [CO2] on grassland ecosystems in Iceland are likely to be reduced by strong down-regulation in the photosynthetic apparatus of the abundant N. stricta species.
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