Data from: Trait responses to AM fungi are stronger and more consistent than fixed differences among populations of Asclepias speciosa

Premise of the study: Arbuscular mycorrhizal (AM) fungi can promote plant
growth and reproduction, but other plant physiological traits or traits
that provide defense against herbivores can also be affected by AM fungi.
However, whether responses of different traits to AM fungi are correlated,
and whether these relationships vary among plants from different
populations is unresolved. Methods: We assessed whether different
populations of the perennial forb, Asclepias speciosa, grown from seed
collected from different environmental conditions across its
distributional range respond differently to AM fungi, and if the responses
of six growth and defense traits are correlated. Key Results: Although
there was strong genetic differentiation in mean trait values among
populations, AM fungi consistently increased expression of most growth and
defense traits across all populations. Responses of biomass and root:shoot
ratio to AM fungi were positively correlated, suggesting that plants that
are more responsive to AM fungi allocated more biomass belowground.
Responses of biomass and trichome density to AM fungi were negatively
correlated, indicating a trade-off in responsiveness between a growth and
defensive trait. Conclusions: Our results suggest that while there is
substantial population differentiation in many traits of A. speciosa,
populations respond similarly to AM fungi, and both positive and negative
correlations among trait responses occur.