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Leaf Life Span Plasticity in Tropical Seedlings Grown under Contrasting Light Regimes
Annals of Botany
Vol. 97, No. 2 (February 2006), pp. 245-255
Published by: Oxford University Press
Stable URL: http://www.jstor.org/stable/42796042
Page Count: 11
You can always find the topics here!Topics: Life span, Plants, Leaves, Sunlight, Seedlings, Leaf area, Nitrogen, Branches, Trees, Tropical rain forests
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• Background and Aims The phenotypic plasticity of leaf life span in response to low resource conditions has a potentially large impact on the plant carbon budget, notably in evergreen species not subject to seasonal leaf shedding, but has rarely been well documented. This study evaluates the plasticity of leaf longevity, in terms of its quantitative importance to the plant carbon balance under limiting light. • Methods Seedlings of four tropical tree species with contrasting light requirements (Alstonia scholaris, Hevea brasiliensis, Durio zibethinus and Lansium domesticum) were grown under three light regimes (full sunlight, 45 % sunlight and 12% sunlight). Their leaf dynamics were monitored over 18 months. • Results All species showed a considerable level of plasticity with regard to leaf life span: over the range of light levels explored, the ratio of the range to the mean value of life span varied from 29 %, for the least plastic species, to 84 %, for the most. The common trend was for leaf life span to increase with decreasing light intensity. The plasticity apparent in leaf life span was similar in magnitude to the plasticity observed in specific leaf area and photosynthetic rate, implying that it has a significant impact on carbon gain efficiency when plants acclimate to different light regimes. In all species, median survival time was negatively correlated with leaf photosynthetic capacity (or its proxy, the nitrogen content per unit area) and leaf emergence rate. • Conclusions Longer leaf life spans under low light are likely to be a consequence of slower ageing as a result of a slower photosynthetic metabolism.
Annals of Botany © 2006 Oxford University Press