Homeostasis of the temperature sensitivity of respiration over a range of growth temperatures indicated by a modified Arrhenius model

The temperature dependence of plant respiratory rate (R) changes in response to growth temperature. Here, we used a modified Arrhenius model incorporating the temperature dependence of activation energy (E_o), and compared the temperature dependence of R between cold-sensitive and cold-tolerant species. We analyzed the temperature dependences of leaf CO₂ efflux rate of plants cultivated at low (LT) or high temperature (HT). In plants grown at HT (HT plants), E_o at low measurement temperature varied among species, but E_o at growth temperature in HT plants did not vary and was comparable to that in plants grown at LT (LT plants), suggesting that the limiting process was similar at the respective growth temperatures. In LT plants, the integrated value of log_e R, a measure of respiratory capacity, in cold-sensitive species was lower than that in cold-tolerant species. When plants were transferred from HT to LT, the respiratory capacity changed promptly after the transfer compared with the other parameters. These results suggest that a similar process limits R at different growth temperatures, and that the lower capacity of the respiratory system in cold-sensitive species may explain their low growth rate at LT.