Table 1.

Effects of CO₂ concentration and planting date on leaf dark respiration at night (R_N; μmol m⁻²·s⁻¹) of X. strumarium

	Dec 31 99		Jan 9 00		Jan 31 00
	365 ppm	730 ppm	365 ppm	730 ppm	365 ppm	730 ppm
Effect of CO2
	1.68  ± 0.32b	2.21  ± 0.47a	1.99  ± 0.47	1.66  ± 0.51	1.40  ± 0.32a	1.00  ± 0.39b
Effect of planting date
0	1.65  ± 0.35	2.14  ± 0.20	1.92  ± 0.56	1.89  ± 0.39	1.58  ± 0.24	0.69  ± 0.28
5	1.59  ± 0.10	1.74  ± 0.49	1.93  ± 0.21	1.35  ± 0.22	1.43  ± 0.18	1.23  ± 0.24
10	1.68  ± 0.16	2.19  ± 0.36	1.59  ± 0.33	1.72  ± 0.22	1.23  ± 0.30	0.85  ± 0.20
15	1.81  ± 0.16	2.78  ± 0.53	2.10  ± 0.60	2.13  ± 0.39	1.42  ± 0.18	1.08  ± 0.23
20			1.93  ± 0.47	1.62  ± 0.53	1.36  ± 0.33	0.80  ± 0.26
25			2.49  ± 0.25	1.26  ± 0.37	1.36  ± 0.22	1.36  ± 0.29

Leaf temperature during respiration measurements was 20.0 ± 0.05°C. Different letters ( 

^a and  

^b) indicate statistical significance at P ≤ 0.05 within the same day. n = 24 for CO₂ treatments and n = 4–6 for planting dates. Mean ± 1 SE.