Table 1. Stomatal density of leaves of Arabidopsis plants grown at elevated or ambient CO₂ in different generations.

Stomatal density		Adaxial surface		decrease	Abaxial surface		decrease
Treatment		AC	EC		AC	EC
Generation	1	216.8±12.6a	176.3±10.0b	18.7%	236.3±12.8a	204.3±10.5b	13.5%
	8	207.2±12.3a	183.2±9.7b	11.6%	231.7±12.6 a	202.8±11.5b	12.5%
	15	219.4±11.6a	188.4±10.3b	14.1%	237.1±11.8 a	210.7±10.8b	11.1%
	SA*	211.6±11.4a	180.5±9.2b	14.7%	240.2±12.1a	213.2±11.8b	11.2%
	SE*	215.5±11.1a	175.4±10.1b	18.6%	234.7±10.9a	205.9±11.2b	12.3%
P-value		0.145–0.869	0.078–0.886	/	0.307–0.921	0.197–0.838	/
Average		214.1	180.8	15.5%	236	207.4	12.1%

The values given indicate means±SD from five plants. Three fully expanded rosette leaves at stage 5.0 were sampled from each of five plants and twenty separate fields were analyzed in each leaf. Mean values were compared by t-test.

^*The seeds used in the reciprocal sowing experiments were from the fifteenth generation grown in ambient CO₂ (SA) and elevated CO₂ (SE).

Abbreviations: AC: Ambient CO₂; EC: Elevated CO₂.