Table II.

Chlorophyll fluorescence quenching and xanthophyll-cycle parameters for LHCIIb

Sample	Quenching	DEPS	Zeaxanthin	V + A + Z
			%
Dark	0.67  ± 0.02	10.0  ± 2.0	0.1  ± 0.05	10.2  ± 2.9
Light	0.71  ± 0.02	62.0  ± 4.0	3.7  ± 0.9	6.3  ± 1.3

Data are shown for LHCIIb isolated from dark-adapted and light-treated leaves. Zeaxanthin content and the xanthophyll-cycle pool of violaxanthin plus antheroxanthin plus zeaxanthin (V + A + Z) are expressed as a percentage of total carotenoid in the sample. “Quenching” is the maximum extent of Chl fluorescence quenching induced by a decrease in pH to 4.2, expressed as a percentage of the F_m. Data are means (±se) of four to five different preparations of LHCIIb.