Seasonal patterns of leaf-level photosynthetic gas exchange in an eastern Amazonian rain forest
Seasonal patterns of leaf-level photosynthetic gas exchange in an eastern Amazonian rain forest
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DOI：
10.1080/17550874.2012.748849
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发表时间：
2014-01-01
影响因子：
1.5
通讯作者：
Ehleringer, James R.
中科院分区：
文献类型：
--
作者：
Domingues, Tomas F.;Martinelli, Luiz A.;Ehleringer, James R.
背景：全球变化正在挑战亚马逊的平衡。了解生物群系如何响应水资源的季节性变化，对于在不久的将来构建生态系统功能的情景至关重要。目的：我们的目的是测试与初级生产力相关的叶性状的季节性变化。方法：化学成分，质量面积比和光合作用对光和CO2的响应曲线以及气孔导度（g（s））对叶-气水分压力差（nu）的响应曲线结果：气孔导度对气孔导度的响应较弱，表明气孔对蒸腾作用的控制有限。旱季气孔限制光合作用不是一个共同的特点，只有一个人研究（出14）表现出伴随减少光饱和光合速率（A（Sat））和g（s）（测量期间A（Sat））与旱季。此外，75%的个人评估没有表现出减少光合能力（V-cmax）在旱季，这表明有限的季节性叶驯化。分组分析表明，大多数参数评价保持不变的季节。例外是叶氮及其同位素签名，并集成气孔对光，CO2和NU.Conclusions的敏感性：这些研究结果加强了这样一个概念，即在亚马逊河流域东部的旱季是不相关的叶级光合作用的显着限制。
Background: Global changes are challenging the equilibrium in the Amazon. Understanding how that biome responds to seasonality in water availability is essential to build scenarios of ecosystem functioning in the near future.Aims: Our aim was to test for seasonal variations in leaf traits related to primary productivity.Methods: Chemical composition, mass to area ratio and photosynthetic response curves to light and CO2 and of stomatal conductance (g(s)) to leaf-to-air water pressure deficit (nu) were determined from leaves of Amazonian trees and lianas.Results: Weak responses of g(s) to nu suggested limited stomatal control over transpiration. Dry season stomatal limitation of photosynthesis was not a common feature as only one individual studied (out of 14) exhibited concomitant decreases in light saturated photosynthetic rate (A(Sat)) and g(s) (measured during A(Sat)) associated with the dry season. Furthermore, 75% of the individuals evaluated did not show decreased photosynthetic capacity (V-cmax) during the dry season, suggesting limited seasonal leaf acclimation. Grouped analyses indicated that most parameters evaluated remained constant across seasons. The exceptions were leaf nitrogen and its isotopic signature, and the integrated stomatal sensitivity to light, CO2 and nu.Conclusions: These findings reinforce the notion that the dry season in eastern Amazonia is not associated with significant limitations in leaflevel photosynthesis.