TY - JOUR
T1 - Differential temperature responses of diurnal and nocturnal leaf respiration in four alpine herbaceous species
AU - Zheng, Tianyu
AU - Kang, Huixing
AU - Yu, Yuan
AU - Guo, Tong
AU - Ke, Xinran
AU - Atkin, Owen K.
AU - Tang, Yanhong
N1 - Publisher Copyright:
© 2025
PY - 2025/3/1
Y1 - 2025/3/1
N2 - Current estimates of diel respiratory carbon release depend on accurate predictions of the temperature sensitivity (Q10) of leaf respiration during the day and night. Such predictions typically rely on measurements of the Q10 of respiration in the light (RL) and dark (RD) made during the day, and assuming that the Q10 of nocturnal respiration (RN) equals that of RD. Using RD as a surrogate for RN, however, creates errors in estimates of diel respiration whenever the Q10 of RD and RN differ. Using measurements made on field-grown, high-altitude alpine plants, our study investigated whether the Q10 of leaf respiration differs between the day and night. We characterised diurnal RL and RD from 15 to 35 °C, and RN from 10 to 25 °C at night, in four common herbaceous species widely distributed in alpine meadows on the Qinghai-Tibetan Plateau. We measured leaf temperature every second for 24 h over a period of 18 days. By combining leaf temperature with respiratory physiological measurements, we calculated leaf carbon loss to assess the consequences of differences in temperature response of leaf respiration between day and night. RN exhibited a higher Q10 than RL and RD by about one third. Although there were no significant differences in Q10 between RL and RD, light inhibition of leaf respiration (i.e. 100 % - RL / RD) was at its lowest at a moderate leaf temperature (22−25 °C). G. straminea and S. pulchra showed lower levels of inhibition than L. sagitta and L. virgaurea. Respiratory carbon loss (Closs_day) based on RN exceeded Closs_day based on RL by up to 47 %, which varied considerably between the species. These results suggest that the temperature sensitivity (Q10) of leaf respiration differs significantly between day and night, a finding that needs to be taken into account when modelling the diel rates of respiratory carbon loss in plants, especially at high altitudes and some high latitudes with a large diurnal variation and low mean temperature. Therefore, considering that neither RN nor RD can accurately represent RL, we strongly recommend that the observations of RL should be prioritized when estimating daytime leaf carbon loss.
AB - Current estimates of diel respiratory carbon release depend on accurate predictions of the temperature sensitivity (Q10) of leaf respiration during the day and night. Such predictions typically rely on measurements of the Q10 of respiration in the light (RL) and dark (RD) made during the day, and assuming that the Q10 of nocturnal respiration (RN) equals that of RD. Using RD as a surrogate for RN, however, creates errors in estimates of diel respiration whenever the Q10 of RD and RN differ. Using measurements made on field-grown, high-altitude alpine plants, our study investigated whether the Q10 of leaf respiration differs between the day and night. We characterised diurnal RL and RD from 15 to 35 °C, and RN from 10 to 25 °C at night, in four common herbaceous species widely distributed in alpine meadows on the Qinghai-Tibetan Plateau. We measured leaf temperature every second for 24 h over a period of 18 days. By combining leaf temperature with respiratory physiological measurements, we calculated leaf carbon loss to assess the consequences of differences in temperature response of leaf respiration between day and night. RN exhibited a higher Q10 than RL and RD by about one third. Although there were no significant differences in Q10 between RL and RD, light inhibition of leaf respiration (i.e. 100 % - RL / RD) was at its lowest at a moderate leaf temperature (22−25 °C). G. straminea and S. pulchra showed lower levels of inhibition than L. sagitta and L. virgaurea. Respiratory carbon loss (Closs_day) based on RN exceeded Closs_day based on RL by up to 47 %, which varied considerably between the species. These results suggest that the temperature sensitivity (Q10) of leaf respiration differs significantly between day and night, a finding that needs to be taken into account when modelling the diel rates of respiratory carbon loss in plants, especially at high altitudes and some high latitudes with a large diurnal variation and low mean temperature. Therefore, considering that neither RN nor RD can accurately represent RL, we strongly recommend that the observations of RL should be prioritized when estimating daytime leaf carbon loss.
KW - CO fluxes
KW - Forbs
KW - Leaf respiration
KW - Light respiration
KW - Qinghai-Tibet Plateau
KW - Temperature sensitivity
UR - http://www.scopus.com/inward/record.url?scp=85214084317&partnerID=8YFLogxK
U2 - 10.1016/j.agrformet.2025.110385
DO - 10.1016/j.agrformet.2025.110385
M3 - Article
AN - SCOPUS:85214084317
SN - 0168-1923
VL - 362
JO - Agricultural and Forest Meteorology
JF - Agricultural and Forest Meteorology
M1 - 110385
ER -