Table 3.

Maximum day and night values of net CO₂ assimilation rate (A) in Bulnesia retama, with the corresponding stomatal conductance (g_s) and C_i/C_a plus late afternoon (18:00) values of A, g_s and C_i/C_a.

Plant	Maximum values						Values 6 h after start of experiment (18:00 h)
	Day			Night
	A (μmol m−2 s−1)	g s (mol m−2 s−1)	C i/Ca	A (μmol m−2 s−1)	g s (mol m−2 s−1)	C i/Ca	A (µmol m−2 s−1)	g s (mol m−2 s−1)	C i/Ca
From Fig. 2 (glasshouse)
Bulnesia retama leaf (Fig. 2A–C)	13.92	0.38	0.82	−0.26	0.06	1.15	11.84	0.25	0.77
Bulnesia retama stem (Fig. 2D–F)	9.71	0.11	0.61	0.87	0.08	0.52	6.84	0.05	0.42
Bulnesia foliosa leaf (C3) Fig. 2G–I)	10.51	0.37	0.88	−0.41	0.04	1.18	7.61	0.26	0.84
Tribulus cistoides (C4) (Fig. 2J–L)	31.18	0.28	0.41	−0.75	0.02	1.10	19.23	0.14	0.34
From Fig. 3 (growth chamber)
Well-watered B. retama stem (Fig. 3A, C, E)	8.04 ± 2.33	0.11 ± 0.02	0.65 ± 0.31	0.42 ± 2.32	0.01 ± 0.02	0.77 ± 0.32	7.43 ± 0.52	0.07 ± 0.02	0.52 ± 0.05
Moderate drought B. retama stem (Fig. 3B, D, F)	8.21 ± 2.07	0.09 ± 0.02	0.58 ± 0.45	0.60 ± 1.99	0.01 ± 0.02	0.71 ± 0.45	8.04 ± 0.56	0.08 ± 0.02	0.56 ± 0.002
From Fig. 4 (glasshouse)
Well-watered B. retama stem (Fig. 4A–C)	7.83	0.10	0.67	−0.14	0.003	1.18	4.19	0.04	0.52
Moderate drought B. retama stem (Fig. 4D–F)	8.97	0.13	0.67	−0.13	0.001	0.34	5.83	0.04	0.40
Severe drought B. retama stem (Fig. 4G–I)	0.50	0.01	0.71	0.68	0.002	–	0.22	0.01	0.80
Severe drought B. retama stem (Fig. 4J–L)	−0.01	0.01	0.97	−0.09	0.004	1.06	−0.33	0.004	1.33

Values are from the 24 h gas-exchange measurements presented in Figs 2–4. The Fig. 3 values are means ± s.e.m.