title: Speed versus endurance tradeoff in plants: Leaves with higher photosynthetic rates show stronger seasonal declines.
abstract: We tested for a tradeoff across species between plant maximum photosynthetic rate and the ability to maintain photosynthesis under adverse conditions in the unfavorable season. Such a trade-off would be consistent with the observed trade-off between maximum speed and endurance in athletes and some animals that has been explained by cost-benefit theory. This trend would have importance for the general understanding of leaf design, and would simplify models of annual leaf carbon relations. We tested for such a trade-off using a database analysis across vascular plants and using an experimental approach for 29 cycad species, representing an ancient plant lineage with diversified evergreen leaves. In both tests, a higher photosynthetic rate per mass or per area in the favorable season was associated with a stronger absolute or percent decline in the unfavorable season. We resolved a possible mechanism based on biomechanics and nitrogen allocation; cycads with high leaf toughness (leaf mass per area) and higher investment in leaf construction than in physiological function (C/N ratio) tended to have lower warm season photosynthesis but less depression in the cool season. We propose that this trade-off, consistent with cost-benefit theory, represents a significant physio-phenological constraint on the diversity and seasonal dynamics of photosynthetic rate.
authors.affiliation: Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China.|Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.|School of Biology and Ecology, University of Maine, Orono, ME 04469, USA.
authors.forename: Yong-Jiang
authors.initials: YJ
authors.lastname: Zhang
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, 621 Charles E. Young Drive South, Los Angeles, CA 90095 1606, USA.
authors.forename: Lawren
authors.initials: L
authors.lastname: Sack
authors.affiliation: Plant Ecophysiology and Evolution Group, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning, Guangxi 530004, China.
authors.forename: Kun-Fang
authors.initials: KF
authors.lastname: Cao
authors.affiliation: National Cycad Germplasm Conservation Center, Fairylake Botanical Garden, Shenzhen and Chinese Academy of Sciences, 160 Xianhu Rd., Liantang, Shenzhen 518004, China.
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Wei
authors.affiliation: National Cycad Germplasm Conservation Center, Fairylake Botanical Garden, Shenzhen and Chinese Academy of Sciences, 160 Xianhu Rd., Liantang, Shenzhen 518004, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Li
mesh_terms: D019684:Magnoliopsida / Q000502:physiology*; D010788:Photosynthesis; D018515:Plant Leaves / Q000502:physiology*; D012621:Seasons; D064028:Tracheophyta / Q000502:physiology*