Data from: Seasonal acclimation of photosynthetic thermal tolerances in six woody tropical species along a thermal gradient

Extreme heat events are becoming increasingly common, and the short-term
acclimation of photosynthesis will have a large impact on plant
performance. Trees in lowland tropical forests, which are hypothesized to
have limited abilities to tolerate rising temperatures, may need to rely
on short term acclimation of their more plastic traits, like
photosynthetic thermal tolerance, to persist in the face of increasingly
variable climates. Here we investigated seasonal acclimation of
thermal tolerances in plant species of the moist Amazon. Specifically, we
measured the photosynthetic thermal tolerances of six common woody
Amazonian species at the beginning and at the end of the dry season to
determine the species’ abilities to acclimate to intra-annual changes to
climate. In addition, we used the natural thermal gradient present at our
research site to test the acclimation of individual plants to maximum air
temperatures not currently observed elsewhere in the moist lowland Amazon
(up to ~43 °C). Between seasons, there were significant overall
increases in the thermal tolerances of three species (i.e., higher thermal
tolerances in the hotter dry season), suggesting that leaf megathermy is
prominent in these species. Also, three species acclimated their thermal
tolerances to microsite-level differences in seasonal temperature maxima,
suggesting closer fidelity between leaf and air temperatures (i.e.,
limited homeothermy) for these species. Our results show that
some woody species from the moist Amazon can acclimate their thermal
tolerances over short time scales, although acclimation is likely
insufficient to overcome thermal stress during extreme temperature events.
Some species may therefore be more sensitive to heatwaves than others,
which could impact survival and composition of tropical lowland forests
into the future.