Survey and synthesis of intra- and interspecific variation in stomatal sensitivity to vapour pressure deficit
Survey and synthesis of intra- and interspecific variation in stomatal sensitivity to vapour pressure deficit
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DOI：
10.1046/j.1365-3040.1999.00513.x
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发表时间：
1999-12-01
影响因子：
7.3
通讯作者：
Schäfer, KVR
中科院分区：
文献类型：
--
作者：
Oren, R;Sperry, JS;Schäfer, KVR
气孔导度 (g(s)) 对增加的蒸气压不足 (D) 的响应通常遵循几个经验函数同样描述的指数下降。然而，下降的幅度（气孔敏感性）在物种内部和物种之间差异很大。在这里，我们使用 g(s) 的孔隙测定和液流通量估计来分析来自各种来源的数据，以评估气孔敏感性与低 D（小于或等于 1 kPa）下的 g(s) 大小成正比的假设。为了测试这种关系，我们使用函数 g(s) = g(sref) - m.InD，其中 m 是气孔敏感性， g(sref) = g(s) at D = 1 kPa，无论物种或方法如何，m 与 gs,ef 高度相关（平均 r(2) = 0.75），斜率约为 0.6。我们证明，该经验斜率与从简单水力模型得出的理论斜率一致，该模型假设叶片水势的气孔调节。理论斜率对于基本假设的偏差和模型参数的变化具有鲁棒性。物种内部和物种之间的关系接近理论预测，无论分析是基于与叶表面 D (D-s) 相关的 g(s) 的气孔测量，还是基于整棵树基于液流的气孔导度 (G(si))，还是与 D 相关的林分水平气孔导度 (G(s))。因此，在低 D 下具有高气孔导度的个体、物种和林分对 D 表现出更大的敏感性，正如气孔调节叶片水势。
Responses of stomatal conductance (g(s)) to increasing vapour pressure deficit (D) generally follow an exponential decrease described equally well by several empirical functions. However, the magnitude of the decrease - the stomatal sensitivity - varies considerably both within and between species, Here we analysed data from a variety of sources employing both porometric and sap flux estimates of g(s) to evaluate the hypothesis that stomatal sensitivity is proportional to the magnitude of g(s) at low D (less than or equal to 1 kPa), To test this relationship we used the function g(s) = g(sref) - m.InD where m is the stomatal sensitivity and g(sref) = g(s) at D = 1 kPa, Regardless of species or methodology, m was highly correlated with gs,ef (average r(2) = 0.75) with a slope of approximately 0.6. We demonstrate that this empirical slope is consistent with the theoretical slope derived from a simple hydraulic model that assumes stomatal regulation of leaf water potential, The theoretical slope is robust to deviations from underlying assumptions and variation in model parameters. The relationships within and among species are close to theoretical predictions, regardless of whether the analysis is based on porometric measurements of g(s) in relation to leaf-surface D (D-s), or on sap flux-based stomatal conductance of whole trees (G(si)), or stand-level stomatal conductance (G(s)) in relation to D. Thus, individuals, species, and stands with high stomatal conductance at low D show a greater sensitivity to D, as required by the role of stomata in regulating leaf water potential.