Biology Commons^™

Genome Size Scaling Through Phenotype Space, Charles A. Knight, Jeremy M. Beaulieu

Biological Sciences

Background and Aims Early observations that genome size was positively correlated with cell size formed the basis of hypothesized consequences of genome size variation at higher phenotypic scales. This scaling was supported by several studies showing a positive relationship between genome size and seed mass, and various metrics of growth and leaf morphology. However, many of these studies were undertaken with limited species sets, and often performed within a single genus. Here we seek to generalize the relationship between genome size and the phenotype by examining eight phenotypic traits using large cross-species comparisons involving diverse assemblages of angiosperm and gymnosperm …

Genome Size Evolution In Relation To Leaf Strategy And Metabolic Rates Revisited, Jeremy M. Beaulieu, Ilia J. Leitch, Charles A. Knight

Biological Sciences

• Background and AimsIt has been proposed that having too much DNA may carry physiological consequences for plants. The strong correlation between DNA content, cell size and cell division rate could lead to predictable morphological variation in plants, including a negative relationship with leaf mass per unit area (LMA). In addition, the possible increased demand for resources in species with high DNA content may have downstream effects on maximal metabolic efficiency, including decreased metabolic rates.

• MethodsTests were made for genome size-dependent variation in LMA and metabolic rates (mass-based photosynthetic rate and dark respiration rate) using our own …

Small Heat Shock Protein Responses Of A Closely Related Pair Of Desert And Coastal Encelia, Charles A. Knight, David D. Ackerly

Biological Sciences

Evolutionary variation for accumulation of small heat shock protein (sHsp) may contribute to thermal niche differentiation between species. Here we examine temperature and time-course-dependent variation for sHsp accumulation in a recently diverged pair of Encelia raised in a common environment: Encelia farinosa, common in the Mojave desert, and Encelia californica, which is found along the cool coastal bluffs of southern North America. Both species exhibit peak sHsp accumulation at 42^oC. Encelia californica accumulated greater levels of sHsp at temperatures below 42^oC, while E. farinosa had greater levels above 42^oC. Encelia farinosa accumulates …