Heat-Induced Quantitative Changes in Carotenoids and Protochlorophyll Precursors in Zea mays

Abstract

When etiolated seedlings of Zea mays were heat-stressed at 45°C for 16 hours in darkness and then illuminated at 25°C, the accumulation of carotenes and protochlorophyllide was retarded while that of xanthophylls, flavones and phytol was enhanced. Phytol accumulation was retarded in dark-grown seedlings. It is concluded that the increased xanthophyll and flavone levels contribute to the heat-induced yellowing of leaves, and that the reduced protochlorophyllide and phytol levels account, at least partly, for the retardation in protochlorophyll accumulation previously reported in heat-stressed seedlings.