Optimum leaf size predicted by a novel leaf energy balance model incorporating dependencies of photosynthesis on light and temperature
Optimum leaf size predicted by a novel leaf energy balance model incorporating dependencies of photosynthesis on light and temperature
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DOI：
10.1007/s11284-011-0905-5
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发表时间：
2012-03-01
影响因子：
2
通讯作者：
Terashima, Ichiro
中科院分区：
文献类型：
--
作者：
Okajima, Yuki;Taneda, Haruhiko;Terashima, Ichiro
为了阐明叶片大小与环境变量之间的关系，我们构建了一个单叶能量平衡模型，该模型结合了莱宁（Leuning）的气孔导度模型和法夸尔（Farquhar）的叶片光合作用模型。我们在各种环境条件下运行该模型，并特别关注叶片边界层。在高光照强度下，使单位叶面积光合作用速率（A）最大化的叶片大小因气温而异。在温暖环境中，A随叶片大小的减小而增加，而在凉爽环境中，存在使A最大化的叶片大小。随着叶片大小的增加，叶片内部的二氧化碳浓度（C(i)）降低，叶片温度升高，这两者都是由于边界层导度较低所致。在低气温下，大叶片中低C(i)对A的负面影响被叶片温度朝着A的最适温度升高所补偿。这种平衡决定了在低气温下A的最适叶片大小。就水分利用效率而言，大叶片往往更具优势，特别是在中低光照强度的凉爽环境中。基于目前的研究结果，对自然界中观察到的一些与温度相关的叶片大小趋势进行了讨论。
To clarify relationships between leaf size and the environment variables, we constructed an energy balance model for a single leaf incorporating Leuning's stomatal conductance model and Farquhar's leaf photosynthesis model. We ran this model for various environmental conditions paying particular attention to the leaf boundary layer. The leaf size maximizing the rate of photosynthesis per unit leaf area (A) at a high irradiance differed depending on the air temperature. In warm environments, A increased with decrease in leaf size, whereas in cool environments, there was the leaf size maximizing A. With the increase in leaf size, the CO2 concentration inside the leaf (C (i)) decreased and the leaf temperature increased, both due to lower boundary layer conductance. At low air temperatures, the negative effect of low C (i) on A in large leaves was compensated by the increase in leaf temperature towards the optimum temperature for A. This balance determined the optimum leaf size for A at low air temperatures. With respect to water use efficiency, large leaves tended to be advantageous, especially in cool environments at low-to-medium irradiances. Some temperature-dependent trends in leaf size observed in nature are discussed based on the present results.