CHANGES IN LEAF PIGMENTS DURING SENESCENCE AND CURING OF FLUE-CURED TOBACCO
Neoxanthin, violaxanthin, lutein, β-carotene, chlorophyll a and chlorophyll b in the leaves of flue-cured tobacco (Nicotiana tabacum L.) were determined in samples collected at intervals from the middle of July through harvest. Harvested leaves were also sampled at intervals during flue curing for pigment determinations. Except where interrupted by rainfall or irrigation, pigment concentrations progressively declined during plant growth; this degradation was accelerated during flue curing. Carotenoid degradation during flue curing was proportional to the degree of oxygen substitution of the carotenoid. Chlorophyll a and chlorophyll b in cured tissue were typically less than 1% of the amounts present at harvest.Key words: Carotenoids, chlorophyll, tobacco (flue-cured), flue curing, senescence