The processes by which the functions of interdependent tissues are coordinated as lineages diversify are poorly understood.
Here, we examine evolutionary coordination of vascular, epidermal and cortical leaf tissues in the anatomically, ecologically and morphologically diverse woody plant family Proteaceae.
We found that, across the phylogenetic range of Proteaceae, the sizes of guard, epidermal, palisade and xylem cells were positively correlated with each other but negatively associated with vein and stomatal densities. The link between venation and stomata resulted in a highly efficient match between potential maximum water loss (determined by stomatal conductance) and the leaf vascular system's capacity to replace that water. This important linkage is likely to be driven by stomatal size, because spatial limits in the packing of stomata onto the leaf surface apparently constrain the maximum size and density of stomata.
We conclude that unified evolutionary changes in cell sizes of independent tissues, possibly mediated by changes in genome size, provide a means of substantially modifying leaf function while maintaining important functional links between leaf tissues. Our data also imply the presence of alternative evolutionary strategies involving cellular miniaturization during radiation into closed forest, and cell size increase in open habitats.
Funding
Australian Research Council
History
Publication title
New Phytologist
Volume
199
Pagination
559-570
ISSN
0028-646X
Department/School
School of Natural Sciences
Publisher
Blackwell Publishing Ltd
Place of publication
Oxford, UK
Rights statement
Copyright 2013 The Authors. New Phytologist Copyright 2013 New Phytologist Trust