Short Periods Of Illumination Research Articles

Protochlorophyll/Chlorophyll Conversion by Single Flash Illumination

Previous studies (Smith and Benitez 1954) have shown the rate of the photochemical conversion of protochlorophyll to chlorophyil‐a in etiolated leaves to be proportional to the product of the light intensity used and the duration of the illumination.This relation, however, is considered to be valid only in the case of moderate light intensities and relatively short periods of illumination. Thus Koski (1950) found a reduction of the total content of pigments in etiolated corn leaves following 180 sec illumination of 150 fc (approximately 1600 lux); she considered this to be a destructive effect of the light. Virgin (1955) found a considerable destruction of chlorophyll to take place in etiolated barley leaves during illumination with 600 fc (about 6500 lux).In the present paper it is shown that by using very high light intensities and very short periods of illumination it is possible to transform approximately 40 percent of the protochlorophyll of etiolated wheat leaves to chlorophyll‐a without effecting any light induced loss of the total content of pigments.