CATALASE ACTIVITY IN CHLOROPLAST PIGMENT DEFICIENT TYPES OF CORN

Abstract

The catalase activity of leaf tissue of various chloroplast pigment deficient types of corn seedlings growing in a greenhouse was detd. by the "catalase tube" method of Knott. The catalase activity of albino seedlings averaged 1.54 ml. of O2 in 5-min. interval, that of yellow seedlings 2.83 ml. and that of green seedlings 10.14 ml. These same chloroplast pigment-deficient types of corn seedlings grown in the dark showed a catalase activity which was surprisingly high in all cases and which was approx. the same for all of the 3 types. The catalase value was usually 1/4 to 1/3 lower in green seedlings grown in the greenhouse than in dark-grown albino, yellow and genetically green corn seedlings. When the dark-grown seedlings were exposed to light there was a rapid photo-oxidation of catalase, so that catalase values approached those of similar aged light-grown seedlings. Under artificial light of 15 f.c. there was a small increase in catalase activity when dark-grown, genetically green corn seedlings were illuminated, instead of the usual 1/4 to 1/3 drop in catalase activity when exposed to brighter light in the greenhouse. Albino and yellow seedlings grown continuously under artificial light of low intensity still showed a much lower catalase value than green corn seedlings of the same age in the same pedigree. In zebra genotype of corn, the light stripes had about the same catalase activity as normal green areas. A series of hybrid strains of corn arranged from darkest green to lightest green showed progressively less catalase activity.