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Adaptive variation in vein placement underpins diversity in a major Neotropical plant radiation

Published version
Peer-reviewed

Type

Article

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Authors

Males, JO 

Abstract

Vein placement has been hypothesised to control leaf hydraulic properties, but the ecophysiological significance of variation in vein placement in the angiosperms has remained poorly understood. The highly diverse Neotropical Bromeliaceae offers an excellent system for exploring understudied relationships between leaf vein placement, physiological functions, and species ecology. To test key hypotheses regarding the links between vein placement, functional type divergences, and ecological diversity in the Bromeliaceae, I characterised the ratio of interveinal distance (IVD) to vein-epidermis distance (VED) in 376 species, representing all major functional types and 10% of the species diversity in the family, as well as bioclimatic properties and key leaf traits for subsets of species. There were significant differences in vein placement parameters in species of contrasting functional type, habitat association, and bioclimatic distribution. In many C3 tank-epiphytes, a greater ratio between interveinal distance and the depth of veins within the mesophyll reflects optimisation for resource foraging in shady, humid habitats. In succulent terrestrials, overinvestment in veins probably facilitates rapid recharge of water storage tissue, as well as restricting water loss. These results highlight how divergences in vein placement relate to distinctive ecophysiological strategies between and within bromeliad functional types, and provide timely insights into how structural–functional innovation has impacted the evolution of ecological diversity in a major radiation of tropical herbaceous angiosperms.

Description

Keywords

anatomy, vasculature, vascular epiphytes, Bromeliaceae, leaf hydraulics

Journal Title

Oecologia

Conference Name

Journal ISSN

0029-8549
1432-1939

Volume Title

185

Publisher

Springer Nature
Sponsorship
NERC (1359020)
JM is funded by Natural Environment Research Council (UK) award 1359020, and received a Bromeliad Society International Harry Luther International Bromeliad Scholarship to carry out research at MSBG.