The Effect of Light and of 2-(4-chlorophenylthio)-triethylamine hydrochloride on Chlorophyll and Carotenoid Contents of Mung Bean Seedlings

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Abstract
Carotenogenesis in mung been seedlings has been shown to be under phytochrome control. Dark-grown seedlings contain more individual carotenoids than light-treated ones, but total carotenoids are greatly increased by light. As expected, chlorophyll was synthesized after a lag period on transferring etiolated seedlings to the light, and there was an increase in total chlorophyll and a parallel increase in total carotenoids. CPTA [2-(4-chlorophenylthio)-triethylamine hydrochloride]-treated seedlings showed a decrease in both total carotenoids and total chlorophylls. The usual effect of CPTA was also observed with mung bean seedlings, namely that lycopene, normally absent, appeared and increased to 17 per cent of total carotenoids after an eight-day treatment. A cis-lycopene, possibly poly-cis-lycopene, was observed for the first time in CPTA-treated tissues. Only in the presence of CPTA but not on its removal was it possible to show an inverse relationship between β-carotene and lycopene. This suggests that CPTA may not act as a cyclase inhibitor in green tissues, cyclase being the enzyme/s involved in the cyclization of carotenes.