Format: ORAL

Adam B. Roddy1, Arezoo Dastpak1, Kevin A. Simonin2

1 Institute of Environment, Department of Biological Sciences, Florida International University, Miami, USA 2 Department of Biology, San Francisco State University, San Francisco, USA

Genome size has been postulated as being a key trait predictive of numerous anatomical, physiological, and ecological traits in plants. While genome size correlates with many organismal traits, the strongest relationship has been with minimum (or meristematic) cell size because a cell cannot be smaller than the volume of its nuclear envelope. Though mature cells are often orders of magnitude larger in volume than the minimum volume defined by the size of the genome, the maximum volume of stomatal guard cellsand possibly other cell typesis invariant across species. These patterns suggest that species with smaller genomes can produce not only smaller cells but also a greater range in mature cell size than species with larger genomes, i.e. smaller genomes may allow for greater plasticity to fine tune anatomy to the environment. Using intraspecific and interspecific data from various experiments and observations, we test the role of genome size in limiting trait plasticity. Our results highlight that while genome size may limit the range of cell sizes a plant can produce, there are multiple alternative ways of overcoming these limitations depending on the functional implications of these traits. Thus, partitioning the effects of genome size from higher-order architectural traits is important for understanding how abiotic conditions may select for leaf traits and, thus, on genome size and, similarly, the distribtuions of genome size across environmental gradients.