Table I.

Effects of various growth conditions leading to different PSII excitation pressures (as measured by V) on the chlorophyll (Chl) and carotenoid content, Chl a/b, and the xanthophyll-cycle pigments pool (A+Z+V) in barley leaves

Growth Condition	V	Total Chl	Chl a/b	Total Carotenoid	A+V+Z
μmol photons m−2 s−1		ng mm−2		ng mm−2
Air
250	0.08	327.9  ± 56.6	2.50  ± 0.11	69.1  ± 12.6	15.1  ± 2.6
400	0.13	386.9  ± 13.4	2.41  ± 0.03	85.9  ± 4.9	18.8  ± 0.4
750	0.25	372.5  ± 3.1	2.62  ± 0.07	76.3  ± 3.2	18.5  ± 0.6
1300	0.47	326.7  ± 42.7	2.76  ± 0.03	74.3  ± 4.5	21.8  ± 0.8
1500	0.52	339.0  ± 47.2	2.72  ± 0.24	84.1  ± 13.2	24.9  ± 2.7
1800	0.60	395.1  ± 17.1	2.73  ± 0.05	110.3  ± 5.9	35.3  ± 4.6
70 ppm CO2, 10% O2
750	0.48	264.3  ± 8.7	2.34  ± 0.05	68.3  ± 0.6	18.5  ± 0.1

Plants were grown for 8 d under the different gas and light conditions. Data are means ± sd of 3 to 10 separate experiments.