Meeting Abstract

S1-2  Friday, Jan. 4 08:00 - 08:30  Linking Plant Scaling Relationships and Ecology OGBURN, R.M.*; EDWARDS, E.J.; DONOGHUE, M.J.; Southern Utah University; Yale University; Yale University

Corner’s rules describe a set of plant morphological scaling relationships between leaves, twigs, and branching density. These scaling relationships are likely dictated by physiological and biomechanical constraints, and are likely to correlate broadly with a species’ ecological strategy. In the angiosperm species that have been studied to date, a broad but consistent relationship between leaves and twigs has been remarkably well supported. However, most of the previously examined species are ecologically similar broad-leaved angiosperm trees of temperate North American and east Asian forests. We followed a two-pronged approach - within a lineage and across ecological communities - to investigate ecological correlates of variation in twig-leaf scaling. Within the lineage Viburnum, which demonstrates significant evolutionary lability in leaf size and shape, we found consistent twig-leaf scaling relationships, with only several showing extreme twig-leaf ratios (leaves that are either “too big” or “too small” for a given twig size). This indicates that during the evolution of leaf morphological diversity in this clade, Corner’s rules have been broadly maintained, suggesting that leaves and stems do not evolve independently. We also tested whether the unique ecological pressures of arid environments would result in different leaf-twig scaling in dryland angiosperms from across many lineages when compared with temperate broadleaved species. Our results confirm that arid-adapted plants also show strong leaf-twig scaling, but the relationship is different: for a given twig diameter the leaves are proportionally smaller compared to broad-leaved plants in non-desert areas. These results within Viburnum and across ecological communities demonstrate divergent but ecologically relevant patterns of twig-leaf scaling in angiosperms, indicating that architectural “rules” are made to be broken.