Table I.

Effect of temperature on maximum carboxylation rates (V_cmax) and R_n measured at ambient atmospheric CO₂ partial pressure (p_a) of 37 Pa and at a low (4–5 Pa) p_i

Temperature	Vcmax	Rn
		Ambient CO2	Low CO2
°C	μmol CO2 m−2 s−1
6	21.1 ± 3.5	0.24 ± 0.03	0.44 ± 0.04
10	27.5 ± 4.6	0.37 ± 0.03	0.48 ± 0.03
15	47.6 ± 11.3	0.64 ± 0.07	0.74 ± 0.08
20	62.7 ± 13.6	1.06 ± 0.03	1.19 ± 0.02
25	72.6 ± 2.0	1.61 ± 0.11	1.72 ± 0.13
30	105.6 ± 2.04	2.48 ± 0.21	2.67 ± 0.04

The V_cmax values were estimated from fitted CO₂-response curves similar to those shown in Figure 1 for measurements done at 2,000 μmol photons m⁻² s⁻¹. V_cmax values for each temperature were calculated according to the method of Von Caemmerer and Farquhar (1981), using data from the CO₂-response curves (e.g. Fig. 1) and the Michaelis-Menten constants for CO₂ and O₂ according to the method of Von Caemmerer et al. (1994). The Γ_^*25 used in these calculations was 4.31 Pa (see “Results”). V_cmax was calculated under the assumption that at the low p_i values shown in Figure 1, photosynthesis was limited by Rubisco only. Values are means of three replicate measurements (±se).