Temperature responses of leaf respiration in light and darkness are similar and modulated by leaf development

Our ability to predict temperature responses of leaf respiration in light and darkness (R-L and R-Dk) is essential to models of global carbon dynamics. While many models rely on constant thermal sensitivity (characterized by Q(10)), uncertainty remains as to whether Q(10) of R-L and R-Dk are actually similar.We measured short-term temperature responses of R-L and R-Dk in immature and mature leaves of two evergreen tree species, Castanopsis carlesii and Ormosia henry in an open field. R-L was estimated by the Kok method, the Yin method and a newly developed Kok-iterC(c) method.<br />When estimated by the Yin and Kok-iterC(c) methods, R-L and R-Dk had similar Q(10) (c. 2.5). The Kok method overestimated both Q(10) and the light inhibition of respiration. R-L/R-Dk was not affected by leaf temperature. Acclimation of respiration in summer was associated with a decline in basal respiration but not in Q(10) in both species, which was related to changes in leaf nitrogen content between seasons. Q(10) of R-L and R-Dk in mature leaves were 40% higher than in immature leaves.<br />Our results suggest similar Q(10) values can be used to model R-L and R-Dk while leaf development-associated changes in Q(10) require special consideration in future respiration models.