The Generality of Leaf Size versus Number Trade-off in Temperate Woody Species
稿件作者：杨冬梅
通讯作者：孙书存
刊物名称：Annals of Botany
发表年份：2008
卷：102
期：4
页码：623-629
影响因子：2.755
文章摘要：
Background and Aims Trade-offs are fundamental to life-history theory, and the leaf size vs. number trade-off has
recently been suggested to be of importance to our understanding leaf size evolution. The purpose of the present
study was to test whether the isometric, negative relationship between leaf size and number found by Kleiman and Aarssen is conserved between plant functional types and between habitats.
Methods Leaf mass, area and number, and stem mass and volume of current-year shoots were measured for 107 temperate broadleaved woody species at two altitudes on Gongga Mountain, south-west China. The scaling relationships of leaf size (leaf area and mass) vs. (mass- and volume-based) leafing intensity were analysed in relation to leaf habit, leaf form and habitat type. Trait relationships were determined with both a standardized major axis method
and a phylogenetically independent comparative method.
Key Results Significant negative, isometric scaling relationships between leaf size and leafing intensity were found
to be consistently conserved across species independent of leaf habit, leaf form and habitat type. In particular, about 99% of the variation in leaf mass across species could be accounted for by proportional variation in mass-based leafing intensity. The negative correlations between leaf size and leafing intensity were also observed across correlated evolutionary divergences. However, evergreen species had a lower y-intercept in the scaling relationships of leaf area vs. leafing intensity than deciduous species. This indicated that leaf area was smaller in the evergreen species at a given leafing intensity than in the deciduous species. The compound-leaved deciduous species were observed usually to have significant upper shifts along the common slopes relative to the simple-leaved species,which suggested that the compound-leaved species were larger in leaf size but smaller in leafing intensity than their simple counterparts. No significant difference was found in the scaling relationships between altitudes.
Conclusions The negative, isometric scaling relationship between leaf size and number is largely conserved in plants, while the leaf size vs. number trade-off can be mediated by leaf properties. The isometry of the leaf size
vs. number relationship may simply result from a biomass allocation trade-off, although a twig size constraint
may provide an alternative mechanism.
recently been suggested to be of importance to our understanding leaf size evolution. The purpose of the present
study was to test whether the isometric, negative relationship between leaf size and number found by Kleiman and Aarssen is conserved between plant functional types and between habitats.
Methods Leaf mass, area and number, and stem mass and volume of current-year shoots were measured for 107 temperate broadleaved woody species at two altitudes on Gongga Mountain, south-west China. The scaling relationships of leaf size (leaf area and mass) vs. (mass- and volume-based) leafing intensity were analysed in relation to leaf habit, leaf form and habitat type. Trait relationships were determined with both a standardized major axis method
and a phylogenetically independent comparative method.
Key Results Significant negative, isometric scaling relationships between leaf size and leafing intensity were found
to be consistently conserved across species independent of leaf habit, leaf form and habitat type. In particular, about 99% of the variation in leaf mass across species could be accounted for by proportional variation in mass-based leafing intensity. The negative correlations between leaf size and leafing intensity were also observed across correlated evolutionary divergences. However, evergreen species had a lower y-intercept in the scaling relationships of leaf area vs. leafing intensity than deciduous species. This indicated that leaf area was smaller in the evergreen species at a given leafing intensity than in the deciduous species. The compound-leaved deciduous species were observed usually to have significant upper shifts along the common slopes relative to the simple-leaved species,which suggested that the compound-leaved species were larger in leaf size but smaller in leafing intensity than their simple counterparts. No significant difference was found in the scaling relationships between altitudes.
Conclusions The negative, isometric scaling relationship between leaf size and number is largely conserved in plants, while the leaf size vs. number trade-off can be mediated by leaf properties. The isometry of the leaf size
vs. number relationship may simply result from a biomass allocation trade-off, although a twig size constraint
may provide an alternative mechanism.
