Thermal Acclimation of Foliar Carbon Metabolism in Pinus taiwanensis Along an Elevational Gradient.

Min Lyu,Mengke Sun,Dongliang Cheng,Josep Peñuelas,Jun Sun,Quanlin Zhong,Xiaoping Chen,Jordi Sardans

doi:10.3389/fpls.2021.778045

Abstract

Climate change could negatively alter plant ecosystems if rising temperatures exceed optimal conditions for obtaining carbon. The acclimation of plants to higher temperatures could mitigate this effect, but the potential of subtropical forests to acclimate still requires elucidation. We used space-for-time substitution to determine the photosynthetic and respiratory-temperature response curves, optimal temperature of photosynthesis (Topt), photosynthetic rate at Topt, temperature sensitivity (Q10), and the rate of respiration at a standard temperature of 25°C (R25) for Pinus taiwanensis at five elevations (1200, 1400, 1600, 1800, and 2000 m) in two seasons (summer and winter) in the Wuyi Mountains in China. The response of photosynthesis in P. taiwanensis leaves to temperature at the five elevations followed parabolic curves, and the response of respiration to temperature increased with temperature. Topt was higher in summer than winter at each elevation and decreased significantly with increasing elevation. Q10 decreased significantly with increasing elevation in summer but not winter. These results showed a strong thermal acclimation of foliar photosynthesis and respiration to current temperatures across elevations and seasons, and that R25 increased significantly with elevation and were higher in winter than summer at each elevation indicating that the global warming can decrease R25. These results strongly suggest that this thermal acclimation will likely occur in the coming decades under climate change, so the increase in respiration rates of P. taiwanensis in response to climatic warming may be smaller than predicted and thus may not increase atmospheric CO2 concentrations.

Highlights

Climate change is becoming increasingly important as a global issue (Grosse et al, 2010; Sendall et al, 2015; Reich et al, 2016)
The temperature response curves of photosynthesis for P. taiwanensis leaves at different elevations followed parabolic curves for both summer and winter
temperature of photosynthesis (Topt) decreased by 1.62◦C for every 1◦C decrease in growth temperature across of P. taiwanensis five elevations in the Wuyi Mountains, accompanied by increases in 1.34 μmol m−2 s−1 of Aopt (Table 1)

Summary

Introduction

Climate change is becoming increasingly important as a global issue (Grosse et al, 2010; Sendall et al, 2015; Reich et al, 2016). Future climatic warming throughout the ranges of species may lead to air and foliar temperatures that exceed current photosynthetic thermal optima, which could reduce photosynthetic capacity and carbon gain and negatively affect plant growth rates and survival (Sage and Kubien, 2007; Valladares et al, 2014). Understanding how these processes vary among different types of climate is a major goal for plant ecology (Wang et al, 2019)

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Discussion

Conclusion