The carbon gain benefits of solar tracking in a desert annual |
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Authors: | H. A. MOONEY J. R. EHLERINGER |
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Affiliation: | Department of Biological Sciences, Stanford University, Stanford, California 94305 U.S.A., and Department of Biology, University of Utah, Salt Lake City, Utah 84112 U.S.A. |
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Abstract: | Abstract. A comparison between two sympatric winter desert annuals, Camissonia claviformis and Malvastrum rotundi folium showed that both gained similar amounts of carbon during a spring day, although by very different means. Camissonia has horizontally fixed leaves which have a very high photosynthetic capacity. The temperature optimum of photosynthesis for this species is near 20°C. Malvastrum has leaves with a lower photosynthetic capacity and a photosynthetic temperature optimum near 30°C. Leaves of the latter species remain normal to the sun throughout the course of the day. The tracking response and high temperature optimum for photosynthesis of Malvastrum result in a high daily carbon gain and also a high water-use efficiency. |
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