Exploring the Role of Adaptation and Acclimation in the Temperature Response of Photosynthesis and Respiration in Southern Pine Species

Abstract

Southern pines provide critical ecosystem services, including supplying the global timber market and playing a major role in regional carbon cycling. Yet, many basic knowledge gaps regarding southern pine physiology remain, including the role of temperature adaptation and acclimation on two major physiological processes related to growth and carbon storage: photosynthesis and respiration. Therefore, we conducted a common garden experiment with three or more geographically distinct populations of loblolly (Pinus taeda), longleaf (Pinus palustris), shortleaf (Pinus echinata) and slash pine (Pinus elliottii). While species demonstrated significant evidence of respiratory adaptation, there was no evidence of species-level photosynthetic adaptation. Additionally, we found that all species demonstrated evidence of photosynthetic and respiratory acclimation, although the mechanism of acclimation varied between species and populations. Quantifying the temperature responses of photosynthesis and respiration in southern pine species can inform models of carbon fluxes and forest-atmosphere interactions in a future shaped by climate change.