Falster Daniel S, Westoby Mark
Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.
New Phytol. 2003 Jun;158(3):509-525. doi: 10.1046/j.1469-8137.2003.00765.x.
• Architecture can vary widely across species. Both steeper leaf angles and increased self-shading are thought to reduce potential carbon gain by decreasing total light interception. An alternative hypothesis is that steeper leaf angles have evolved to improve day-long carbon gain by emphasising light interception from low angles. • Here we relate variation in architectural properties (leaf angle and leaf size) to cross-species patterns of leaf display, light capture and simulated carbon gain in branching-units of 38 perennial species occurring at two sites in Australian forest. Architectural comparison was made possible by combining 3D-digitising with the architecture model YPLANT. • Species with shallow angled leaves had greater daily light interception and potentially greater carbon gain. Self-shading, rather than leaf angle, explained most variance between species in light capture and potential carbon gain. Species average leaf size was the most important determinant of self-shading. • Our results provide the first cross-species evidence that steeper leaf angles function to reduce exposure to excess light levels during the middle of the day, more than to maximise carbon gain.
• 植物结构在不同物种间差异很大。叶片角度更陡和自我遮荫增加都被认为会通过减少总光截获量来降低潜在的碳增益。另一种假设是，更陡的叶片角度是为了通过强调从低角度的光截获来提高全天的碳增益。
• 在这里，我们将结构特性（叶片角度和叶片大小）的变化与澳大利亚森林两个地点的38种多年生植物分支单元中的叶片展示、光捕获和模拟碳增益的跨物种模式联系起来。通过将三维数字化与YPLANT结构模型相结合，实现了结构比较。
• 叶片角度浅的物种具有更大的每日光截获量，潜在碳增益可能更大。自我遮荫而非叶片角度解释了物种间在光捕获和潜在碳增益方面的大部分差异。物种平均叶片大小是自我遮荫的最重要决定因素。
• 我们的结果提供了首个跨物种证据，表明更陡的叶片角度的作用是减少中午期间暴露于过量光照水平，而不仅仅是使碳增益最大化。
