Table 1.

Summary of statistics for gas exchange parameters

Parameter (mean plant−1)	Measurement		13 WAP	17 WAP
	Temperature °C	CO2 (μl l−1)	Main effects	Main effects		Interaction
			CO2	CO2	HS	CO2×HS
A (µmol m−2 s−1)	25	400	**	*	*	**
		650	**	**	*	**
	35	400	**	NS	NS	*
		650	**	NS	NS	*
R d (µmol m−2 s−1)	25	400	NS	NS	NS	NS
	35	400	*
g s (mol m−2 s−1)	25	400	NS	*	*	NS
		650	NS	**	**	*
	35	400	NS	NS	NS	NS
		650	NS	NS	NS	NS
PWUE (A/gs)	25	400	NS	NS	NS	NS
		650	NS	NS	NS	NS
	35	400	NS	NS	*	*
		650	NS	NS	NS	NS
F v/Fm	25	400	NS	*	NS	NS
F v'/Fm'	25	400	NS	**	**	*
A (µmol m−2 s−1)	25	Growth CO2	**	***	NS	**
	35		***	**	NS	*
R d (µmol m−2s−1)	25		***
	35		*
g s (mol m−2 s−1)	25		NS	***	**	*
	35		NS	NS	NS	NS
PWUE (A/gs)	25		***	***	NS	*
	35		**	***	NS	NS

Summary of statistical analysis using two-way ANOVA for the effects of elevated CO₂ and heat stress (HS) on leaf gas exchange parameters measured at 13 and 17 weeks after planting (WAP). HS plants were measured at the recovery stage (n=9–10). Significance levels are **P<0.001; ** P <0.01; * P <0.05; NS, P>0.05.