Drought Effects on Photosynthesis and Implications of Photoassimilate Distribution in 11C-Labeled Leaves in the African Tropical Tree Species Maesopsis eminii Engl.
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Date
2018
Journal Title
Journal ISSN
Volume Title
Publisher
Forests
Abstract
Photoassimilate distribution inside leaves is less studied than photosynthesis, and yet
the topic is important as it gives insights into the vital roles played by leaves in plant survival.
We combined greenhouse measurements of light response curves with 11C-labelling using leaves
of 3-year-old potted Maesopsis eminii Engl. trees to improve our understanding of its leaf carbon
physiology. This fast-growing pioneer tree species showed low photosynthetic rates for a common
tropical pioneer during well-watered reference conditions (5.0 0.7 mol m2 s1), which
further decreased in response to drought. 11C-autoradiography indicated active phloem loading
and/or rapid phloem transport rates. Active loading is uncommon in tree species, but might be
related to deciduousness traits and continuous investment in growth, like in herbaceous active
loaders. Active loading involves higher carbon allocation to growth, which might explain why
low photosynthetic rates were observed in this fast-growing species. These findings suggest that
examining photoassimilate distribution and transport may be critical for understanding the role tree
physiology plays in terrestrial carbon cycling.
Description
Keywords
African tropical tree, 11C autoradiographs, drought, light response curve, Maesopsis eminii Engl., photoassimilate distribution, leaf carbon balances, leaf photosynthesis and respiration
Citation
Epila, J., Hubeau, M., & Steppe, K. (2018). Drought Effects on Photosynthesis and Implications of Photoassimilate Distribution in 11C-Labeled Leaves in the African Tropical Tree Species Maesopsis eminii Engl. Forests, 9(3), 109.