Data from: Importance of whole-plant biomass allocation and reproductive timing to habitat differentiation across the North American sunflowers

Background and Aims: Trait-based plant ecology attempts to use small
numbers of functional traits to predict plant ecological strategies.
However, a major gap exists between our understanding of organ-level
ecophysiological traits and our understanding of whole-plant fitness and
environmental adaptation. In this gap lie whole-plant organizational
traits, including those that describe how plant biomass is allocated among
organs and the timing of plant reproduction. This study explores the role
of whole-plant organizational traits in adaptation to diverse environments
in the context of life history, growth form and leaf economic strategy in
a well-studied herbaceous system. Methods: A phylogenetic comparative
approach was used in conjunction with common garden phenotyping to assess
the evolution of biomass allocation and reproductive timing across 83
populations of 27 species of the diverse genus Helianthus (the
sunflowers). Key Results: Broad diversity exists among species in both
relative biomass allocation and reproductive timing. Early reproduction is
strongly associated with resource-acquisitive leaf economic strategy,
while biomass allocation is less integrated with either reproductive
timing or leaf economics. Both biomass allocation and reproductive timing
are strongly related to source site environmental characteristics,
including length of the growing season, temperature, precipitation and
soil fertility. Conclusions: Herbaceous taxa can adapt to diverse
environments in many ways, including modulation of phenology, plant
architecture and organ-level ecophysiology. Although leaf economic
strategy captures one key aspect of plant physiology, on their own leaf
traits are not particularly predictive of ecological strategies in
Helianthus outside of the context of growth form, life history and
whole-plant organization. These results highlight the importance of
including data on whole-plant organization alongside organ-level
ecophysiological traits when attempting to bridge the gap between
functional traits and plant fitness and environmental adaptation.