January 11 2017

11:00 158 HH

Lisa Donovan
Department of Plant Biology, University of Georgia

Evidence for and against evolution of a whole plant economics spectrum in wild Helianthus


The well described leaf economic spectrum (LES) and hypothesized whole plant economic spectrum (PES) have gained attention as patterns of co-variation among plant traits related to resource use across large numbers of species. They are argued to reflect evolutionary tradeoffs that lead to a spectrum of plant ecological and evolutionary strategies. However, an understanding of the mechanisms underlying the LES and PES requires an understanding of the sources of variation encompassed in the patterns and robust tests of evolutionary hypotheses. We explore the magnitude of different sources of variation for LES and PES traits and test for hypothesized correlated evolution of traits and adaptive differentiation, using the Helianthus study system. We demonstrate that variation accounted for by relatedness, ontogenetic and environmental components can be large in magnitude and affect interpretations. When these sources are variation are taken into consideration in phylogenetically informed comparisons of Helianthus species in a common garden greenhouse studies, we find evidence of correlated evolution and adaptive differentiation for many (but not all) PES leaf and stem traits, but not for most root traits, providing only partial support for the hypothesized PES. This contributes to a growing number of phylogenetically informed studies that will enable us to assess the universality of hypothesized evolutionary tradeoffs among LES and PES traits, and explore underlying mechanisms of selection and constraints.











































































































































































































































































































































































































































































































































































































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