Laboratory of Plant Physiology, Department of Agricultural Biotechnology, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.
Am J Bot. 2009 Mar;96(3):612-9. doi: 10.3732/ajb.0800166.
Tree and shrub species can be differentiated into two major groups based on their substantially different leaf anatomy: heterobaric and homobaric. In contrast to homobaric leaves, heterobaric leaves have bundle sheath extensions (BSEs) that create transparent regions on their lamina. Recent studies have shown that BSEs transfer visible light to internal mesophyll layers, thus affecting the photosynthetic performance of heterobaric leaves. Whether the two leaf types also differ in other functional and structural traits has not been addressed, nor have any structure-function relations. Here, we measured key anatomical and physiological parameters and tested their relationships in 30 species with different leaf types. Heterobaric leaves were thinner with lower leaf mass per area, had higher nitrogen concentration per mass, were (13)C-enriched, and achieved comparable photosynthetic capacity per area but had higher photosynthetic capacity per mass compared to homobaric leaves. Relations between leaf construction cost, nitrogen concentration, and photosynthesis followed the general pattern of the "leaf economic spectrum," but differed between homobaric and heterobaric leaves. We suggest that the mechanisms controlling these relations differ between the two leaf types, presumably due to their distinct anatomy.
异形叶和同形叶。与同形叶相比，异形叶具有束鞘延伸（BSE），在叶片上形成透明区域。最近的研究表明，BSE 将可见光转移到内部叶肉层，从而影响异形叶的光合作用性能。两种叶片类型在其他功能和结构特征上是否存在差异，以及任何结构-功能关系都没有得到解决。在这里，我们测量了 30 种不同叶型物种的关键解剖学和生理学参数，并测试了它们之间的关系。异形叶较薄，比叶面积质量较低，每质量氮浓度较高，（13）C 富集，比同形叶具有相当的比叶面积光合能力，但比同形叶具有更高的比叶质量光合能力。叶片构建成本、氮浓度和光合作用之间的关系遵循“叶片经济谱”的一般模式，但在同形叶和异形叶之间存在差异。我们认为，控制这些关系的机制在两种叶片类型之间存在差异，这可能是由于它们不同的解剖结构。
