Fig. 2. Concepts explained.

a Conceptual figure of how R_T (rate of respiration at varying temperature) is measured in response to either (i) common short-term rapid artificial cooling (e.g. during 10–30 min) of leaf/plant can be used to calculate Q_10,inh (inherent temperature sensitivity of R, Equation 1, using point connected by the grey dashed line), or (ii) natural cooling (over several hours) of the environment along temporal variation in T can be used to calculate Q_10,app (apparent temperature sensitivity of R, Equation 1, using the points connected by the blue dashed line). The decrease in R_T due to change in T alone is denoted α and the further observed decrease in R is denoted β. Common practise is also to extrapolate (represented by a short-dashed curve) how R_T is assumed to change (open symbol) with T-change further into the night than the actual measured T-change (long dashed curve). b Box-and-whisker plots (The centre line is the median. The lower whisker is the lowest datum above the first quartile − 1.5 × interquartile range. The upper whisker is the highest datum below the first quartile − 1.5 × interquartile range. Any points outside the whiskers are plotted separately) of Q_10,app, Q_10,inh, and TC (temperature control) of R (α/(α + β)) across ten species (46 replicate plants, Supplementary Table 2). c Dependence of Q₁₀ and TC of R on the rate of nocturnal cooling. In the example shown, it was assumed Q_10,inh = 2.0. Q_10,app and TC were calculated as described in Fig. 2a assuming that R,_To/R,_To-initial = 1–0.08 × h^0.54 (Fig. 1a). TDQ₁₀ = 3.09 − 0.0435 × T (temperature-dependent Q₁₀, ref. 22, Equation 2). d Modelled nocturnal variations in R in response to T decrease during the night, including and excluding effects of non-temperature control on metabolism. R_T = R_To × Q_10,inh ^[(T-To)/10], where R_To-initial = 2.5 and Q_10,inh = 2. Grey symbols represent constant R_To and a T decrease of 0.5 °C/h. Blue symbols represent R_To/R_To-initial = 1 – 0.08 × h^0.54 (Fig. 1a) and a temperature decrease of 0.5 °C/h. Dashed area is the cumulated difference in nocturnal R with time throughout the night without and with non-temperature control. Data are available in Supplementary Data 4.