Table 1.

Pigment composition and NPQ values for intact spinach chloroplasts

Sample	Neo	Lut	XC	DEPs%	chl a/b	NPQ
Dark Vio	45 ± 2.8	122 ± 3	50 ± 2.8	0	3.5 ± 0.1	0
Light Vio	44 ± 1.6	122 ± 2	49 ± 1.1	0	3.4 ± 0.09	0.6 ± 0.1*
Light Zea	45 ± 1.1	121 ± 2	49 ± 1.3	35 ± 1.3*	3.5 ± 0.1	2.1 ± 0.1*
Dark Zea	46 ± 0.8	120 ± 3	49 ± 2.1	36 ± 3.7*	3.5 ± 0.07	0.3 ± 0.03*
Light + nigericin	44 ± 2.4	121 ± 3	50 ± 2.3	0	3.4 ± 0.1	0

Chloroplasts devoid of zeaxanthin and antheraxanthin (Vio) and chloroplasts enriched in zeaxanthin (Zea) were light treated for 5 min at 350 µmol photons m⁻² s⁻¹ to form NPQ and then either immediately frozen for pigment analysis (Light Vio and Light Zea chloroplasts) or given a further 5 min of darkness to allow NPQ to relax prior to freezing for pigment analysis. A separate sample of Vio chloroplasts were light treated at 350 µmol photons m⁻² s⁻¹ for 5 min in the presence of 2 µM nigericin (Light + nigericin). Data are expressed as mmoles carotenoids per mole chlorophyll a + b molecules and are means ± S.E.M. from four replicates. Neo, Lut, XC, DEPs and chl a/b, NPQ: correspond to neoxanthin, lutein, xanthophyll cycle carotenoids (violaxanthin, antheraxanthin, zeaxanthin), xanthophyll cycle de-epoxidation state [(Z + 0.5A)/(V + A + Z)]%, chlorophyll a/b ratio, the amount non-photochemical quenching in each sample as calculated from chlorophyll fluorescence traces as shown in Figure 1. Statistical confidence levels *indicates significantly different with respect to dark adapted sample p < 0.01, using an AN OVA analysis (Tukey contrast).