Densities of leaf minor veins and stomata


Vein density is independent of epidermal cell size in Arabidopsis mutants

by Carins Murphy M. R., Dow G. J., Jordan G. J., Brodribb T. J. (2017)

Madeline R. Carins Murphy, University of Tasmania, Hobart, Australia.
Graham J. Dow, Boston University, Boston, MA, USA.
Gregory J. Jordan, University of Tasmania, Hobart, Australia.
Timothy J. Brodribb, University of Tasmania, Hobart, Australia
A School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tas. 7001, Australia.
B Department of Biology, Boston University, 5 Cummington Mall, Boston, MA 02 215, USA.


in Functional Plant Biology – – published online 9 January 2017 –

Densities of leaf minor veins and stomata are co-ordinated within and across vascular plants. This maximises the benefit-to-cost ratio of leaf construction by ensuring stomata receive the minimum amount of water required to maintain optimal aperture.
A ‘passive dilution’ mechanism in which densities of veins and stomata are co-regulated by epidermal cell size is thought to facilitate this co-ordination. However, unlike stomata, veins are spatially isolated from the epidermis and thus may not be directly regulated by epidermal cell expansion.
Here, we use mutant genotypes of Arabidopsis thaliana (L.) Heynh. with altered stomatal and epidermal cell development to test this mechanism. To do this we compared observed relationships between vein density and epidermal cell size with modelled relationships that assume veins and stomata are passively diluted by epidermal cell expansion.
Data from wild-type plants were consistent with the ‘ passive dilution’ mechanism, but in mutant genotypes vein density was independent of epidermal cell size. Hence, vein density is not causally linked to epidermal cell expansion.
This suggests that adaptation favours synchronised changes to the cell size of different leaf tissues to coordinate veins and stomata, and thus balance water supply with transpirational demand.

Vein density is independent of epidermal cell size in Arabidopsis mutants. Available from: [accessed Jan 12, 2017].



Published by

Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.

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