Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California 90095-1606, USA.
Am J Bot. 2013 Oct;100(10):1936-48. doi: 10.3732/ajb.1200608. Epub 2013 Sep 26.
Allometric relationships among the dimensions of leaf cells, cell walls, and tissues, and whole-leaf thickness and area are likely to have key implications for leaf construction and function, but have remained virtually untested, despite the explosion of interest in allometric analysis of numerous plant properties at larger scales. •
Using leaf transverse cross sections and light microscopy, we measured leaf dimensions, tissue thicknesses, mesophyll and xylem cell sizes, and cell wall thicknesses for 14 diverse angiosperm species of wet and dry habitats and tested hypothesized allometric relationships based on geometric scaling due to development and/or function. •
We found strong novel allometries relating the dimensions of cells, cell walls, tissues, and gross leaf form. Cell sizes and cell wall thicknesses tended to scale isometrically across mesophyll tissues within the leaf, such that species with large cells or thick cell walls in one tissue had these also in the other tissues; however, leaf vein xylem conduit sizes were independent of those of other cell types. We also found strong geometric scaling of cell wall thicknesses with cell sizes throughout the mesophyll, but not in the leaf vein xylem. Further, leaf thickness scaled with cell sizes, cell wall thicknesses and the thicknesses of component mesophyll tissues, but leaf area was independent of anatomical traits across species. •
These novel allometries suggest design rules operating at the smallest scales of leaf construction and the possibility of applying these relationships to better characterizing the basis for differences among species in leaf form and functional traits.
叶片细胞、细胞壁和组织的维度，以及整叶厚度和面积之间的异速关系可能对叶片结构和功能具有关键意义，但尽管人们对更大尺度上众多植物属性的异速分析产生了浓厚的兴趣，但这些关系几乎没有得到实际检验。
使用叶片横切面和光学显微镜，我们测量了 14 种不同生境的被子植物的叶片维度、组织厚度、叶肉和木质部细胞大小以及细胞壁厚度，并根据发育和/或功能的几何比例关系检验了假设的异速关系。
我们发现了与细胞、细胞壁、组织和叶片整体形态的维度有关的强烈新型异速关系。细胞大小和细胞壁厚度在叶片内的叶肉组织中呈等比缩放，因此在一种组织中具有较大细胞或较厚细胞壁的物种在其他组织中也具有这些特征；然而，叶脉木质部导管的大小与其他细胞类型无关。我们还发现了叶肉中细胞壁厚度与细胞大小之间的强烈几何比例关系，但叶脉木质部中没有。此外，叶片厚度与细胞大小、细胞壁厚度和组成叶肉组织的厚度呈比例缩放，但叶片面积在物种间与解剖特征无关。
这些新的异速关系表明，在叶片结构的最小尺度上存在设计规则，并且有可能应用这些关系来更好地描述物种间在叶片形态和功能特征上的差异的基础。
