Variation in leaf temperatures of tropical and subtropical trees are related to leaf thermoregulatory traits and not geographic distributions dataset

To predict the effects of global warming on plants, previous studies have
investigated how the distributions and physiological performances of
plants relate to environmental temperatures. This approach implicitly
assumes that leaf temperatures are tightly linked with regional air
temperatures. However, the thermoregulatory behaviors and physical
properties of leaves can differ greatly between species, leading to
different plants having different leaf temperatures even when occurring
under similar conditions. It is important to understand this variation in
leaf thermoregulatory traits and temperatures in order to predict how
individual species will be impacted by global warming. We measured the
thermal properties of leaves from >50 tropical and subtropical tree
species grown at the Gifford Arboretum (Florida, USA). For each species we
measured maximum leaf temperature and rate of leaf warming using a new
standardized protocol to control for both environmental variation and
select plant thermoregulatory behaviors. We tested the relationships
between the thermal variables and several leaf functional traits. Even
under laboratory-controlled conditions, leaf temperatures varied by over
8.5oC amongst species. Maximum leaf temperature was positively correlated
with leaf area and rate of leaf warming was negatively correlated with
water content per leaf area. This suggests that some species may be able
to offset rising air temperatures through acclimation or adaptation of
leaf properties. Next, we tested the relationships between the species’
leaf thermal properties and their climatic niches/distributions, but we
found no significant associations. These results call into question the
use of regional air temperatures to model plant physiological and
demographic performance.