The scaling relationship between either leaf dry or fresh mass (M) and surface area (A) can reflect the photosynthetic potential and efficiency of light harvesting in different broad-leaved plants. In growing leaves, lamina area expansion is typically finished before the completion of leaf biomass accumulation, thereby affecting the M vs. A scaling relationship at different developmental stages of leaves (e.g., young vs. adult leaves). In addition, growing plants can have different-sized leaves at different plant ages, potentially also changing M vs. A scaling. Furthermore, leaf shape can also change during the course of ontogeny and modify the M vs. A scaling relationship. Indeed, the effect of seasonal changes in leaf shape on M vs. A scaling has not been examined in any previous studies known to us. The study presented here was conducted using two deciduous tree species: Alangium chinense (saplings forming leaves through the growing season) and Liquidambar formosana (adult trees producing only one leaf flush in spring) that both have complex but nearly bilaterally symmetrical leaf shapes. We determined (i) whether leaf shapes differed in spring versus summer; (ii) whether the M vs. A scaling relationship varied over time; and (iii) whether there is a link between leaf shape and the scaling exponent governing the M vs. A scaling relationship. The data indicated that (i) the leaf dissection index in spring was higher than that in summer for both species (i.e., leaf-shape complexity decreased from young to adult leaves); (ii) there was a significant difference in the numerical value of the scaling exponent of leaf perimeter vs. area between leaves sampled at the two dates; (iii) spring leaves had a higher water content than summer leaves, and the scaling exponents of dry mass vs. area and fresh mass vs. area were all greater than unity; (iv) the scaling relationship between fresh mass and area was statistically more robust than that between leaf dry mass and area; (v) the scaling exponents of leaf dry and fresh mass vs. area of A. chinense leaves in spring were greater than those in summer (i.e., leaves in younger plants tend to be larger than leaves in older plants), whereas, for the adult trees of L. formosana, the scaling exponent in spring was smaller than that in summer, indicating increases in leaf dry mass per unit area with increasing leaf age; and (vi) leaf shape appears not to be related to the scaling relationship between either leaf dry or fresh mass and area, but is correlated with the scaling exponent of leaf perimeter vs. area (which tends to be a ½ power function). These trends indicate that studies of leaf morphometrics and scaling relationships must consider the influence of seasonality and plant age in sampling of leaves and the interpretation of data.

中文翻译：

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两种落叶树种春夏叶片生物量与表面积比例关系的比较

叶片干燥或新鲜质量（M）与表面积（A）之间的比例关系可以反映不同阔叶植物的光合作用潜力和光收集效率。在越来越多的叶子，叶片面积扩大通常叶生物量积累完成前完成，从而影响了中号与一个在叶子的不同发育阶段（例如，年轻的成年人与叶）比例关系。此外，生长中的植物在不同的植物年龄下可能具有不同大小的叶子，可能也会改变M与A的比例。此外，叶片形状还可以在个体发育过程中改变，并改变M vs.。一个比例关系。事实上，对叶形季节性变化的影响中号与一个比例尚未在我们已知的任何以前的研究调查。这里介绍的研究是使用两种落叶乔木进行的：Alangium chinense（树苗在整个生长季节形成叶子）和Liquidambar formosana（成年树在春季仅产生一叶齐平），它们均具有复杂但几乎两侧对称的叶片形状。我们确定（i）春季和夏季叶片形状是否不同；（ⅱ）是否中号对甲随时间变化的缩放关系; （iii）叶片形状和控制叶片的缩放指数之间是否存在联系中号与一个比例关系。数据表明：（i）两种叶片的春季叶片解剖指数均高于夏季（即叶片形状复杂度从幼叶到成年叶片均降低）；（ii）在两个日期采样的叶片之间，叶片周长的比例指数与面积之间的比例指数的数值存在显着差异；（iii）春叶的水分含量高于夏叶，并且干重与面积和新鲜重与面积的比例指数均大于1。（iv）鲜食量和面积之间的比例关系在统计上比叶干量和面积之间的比例关系更稳健；（v）叶片干燥和新鲜质量的缩放指数与中华按蚊面积的关系叶春季较夏季更高（即叶植物年龄往往比在老厂叶大），而对于成年树枫香，春季标度指数明显高于夏季较小，表明随着叶龄的增加，单位面积的叶片干重增加；（vi）叶​​片形状似乎与叶片干燥或新鲜质量与面积之间的比例关系无关，但与叶片周长与面积的比例指数相关（往往是1/2幂函数）。这些趋势表明，叶片形态和比例关系的研究必须考虑季节和植物年龄对叶片采样和数据解释的影响。