Chlorophyll Synthesis in a Yellow Mutant of Wheat

Abstract

A spontaneous non-lethal chlorophyll mutant of hexaploid wheat was shown to have a greatly diminished rate of chlorophyll accumulation compared to the wild type when 8-day-old dark-grown plants were illuminated with white light. The rate of conversion of protochlorophyllide to chlorophyll was approximately the same in both types. When leaves from dark-grown plants were incubated in ´-aminolaevulinate, protoporphyrin and protochlorophyll accumulated in the mutant whereas larger amounts of protochlorophyll accumulated in the wild type. It was concluded that the mutation brings about a restriction in the rate of conversion of protoporphyrin to magnesium protoporphyrin and its methyl ester. The effect of the mutation on protoporphyrin and protochlorophyll accumu- lation was intensified in crosses of the mutant with lines deficient in one of the No. 7 chromosomes, which control chlorophyll synthesis.