CHARACTERIZATION OF CAROTENOID ACYL ESTERS PRODUCED IN DROUGHT-STRESSED BARLEY SEEDLINGS

Drought-stressed barley seedlings have been adopted as a model system in which to examine the biochemistry of senescence. Unwatered barley seedlings develop yellow patches on their leaves after about 5 days. Analyses of the pigment composition by reversed-phase HPLC revealed significantly decreased chlorophyll content relative to the carotenoid pigments. Among the carotenoids appeared significant amounts of apolar compounds, xanthophyll esters, that are not normally found in light-grown, green tissue of barley. Mass spectrometric analysis, partial synthesis and co-chromatography on reversed-phase HPLC confirmed that the main carotenoid ester was lutein bis-linolenate.