Thermal acclimation of leaf respiration is consistent in tropical and subtropical populations of two mangrove species

Abstract

Summary Populations from different climates often show unique growth responses to temperature, reflecting temperature adaptation. Yet, whether populations from different climates differ in physiological temperature acclimation remains unclear. Here, we test whether populations from differing thermal environments exhibit different growth responses to temperature and differences in temperature acclimation of leaf respiration. We grew tropical and subtropical populations of two mangrove species (Avicennia germinans, Rhizophora mangle) under ambient and experimentally warmed conditions in common garden at the species’ northern range limit. We quantified growth and temperature responses of leaf respiration (R) at seven timepoints over ~10 months. Warming increased productivity of tropical populations more than subtropical populations, reflecting a higher temperature optimum for growth. In both species, R measured at 25 °C declined as seasonal temperatures increased, demonstrating thermal acclimation. Contrary to our expectations, acclimation of R was consistent across populations and temperature treatments. However, populations differed in adjusting the temperature sensitivity of R (Q10) to seasonal temperatures. Following a freeze event, tropical Avicennia showed greater freeze damage than subtropical Avicennia while both Rhizophora populations appeared equally susceptible. We found evidence of temperature adaptation at the whole-plant scale but little evidence for population differences in thermal acclimation of leaf physiology. Studies that examine potential costs and benefits of thermal acclimation in an evolutionary context may provide new insights into limits of thermal acclimation.

Pushing the envelope: do narrowly and widely distributed Eucalyptus species differ in response to climate warming?

“…Here, we focus on ‘acclimation capacity’ to reflect physiological adjustments at the scale of leaves, primarily relating to the photosynthesis and respiration. There is evidence that tree species from more thermally variable temperate regions tend to have higher acclimation capacity and respond more positively to warming than tree species from tropical regions, which are less seasonal (Cunningham & Read, 2002, 2003; Doughty & Goulden, 2008; Way & Oren, 2010; Vårhammar et al ., 2015), although this is not always the case (Choury et al ., 2022; Chieppa et al ., 2023). There is also evidence of differential warming impacts across populations of species spanning large latitudinal gradients, often with stronger negative warming impacts on tree growth in warm environments (Rehfeldt et al ., 2002; Reich & Oleksyn, 2008; Molina‐Montenegro & Naya, 2012; Drake et al ., 2015, 2017b).…”