Angiosperm leaf vein patterns are linked to leaf functions in a global-scale data set

Abstract

Premise of the study: Leaves are plants' primary interface with the atmosphere and affect a range of ecological processes. Vein patterns are one of the most prominent aspects of leaf form, and the functional significance of different vein patterns is gaining increasing attention. Methods: Phylogenetic and standard ANOVA and regression were used to provide the first global-scale, phylogenetically based test of relations between angiosperm vein patterns and leaf functional traits. Pagel' s λ was used to test for phylogenetic signal in all traits. Key results: All leaf traits had significant phylogenetic signal. Significant phylogenetically based relations were found between secondary vein pattern and leaf functions, linking leaf form to the well-known trade-off between physiological activity and leaf life span. The relations between primary vein pattern and leaf functions were not found to be significant with phylogenetic tests, suggesting these relations may be the result of changes within a few lineages, followed by phylogenetic conservatism, rather than multiple instances of correlated trait evolution. The relation between minor vein density and maximum photosynthetic rate was found to be marginally nonsignificant with phylogenetic regression, which does not rule out coordinated evolution of hydraulic supply and demand. Conclusions: Although phylogenetic conservatism may weaken statistical relations between vein patterns and leaf functions, phylogenetic relations can provide a complementary source of information for inferring unmeasured values of leaf traits. Relations among vein patterns, leaf functions, and phylogeny will be valuable for estimating functional attributes of living and fossil plant species and communities. © 2011 Botanical Society of America.