Changes in Catalase Activity and Other Responses Induced in Plants by Red and Blue Light.

In an earlier paper (1) it was reported that etiolated barley seedlings when exposed to visible radiation suffer a large decrease in catalase activity and a simultaneous increase in chlorophyll. Eyster (4) found that dark-grown genetic albino corn seedlings, completely devoid of chlorophyll, also suffer a loss in catalase activity when illuminated. There are several earlier studies such as Knott (7) that report the effects of light on the catalase activity of growing plants. In all these studies light of the whole visible spectrum was used. Since it is apparent that the decrease in catalase involves a photochemical reaction, it is reasonable to assume that certain regions of the spectrum may be more effective than others. We initially planned to determine the action spectrum for this process, but difficulties involved in obtaining light of relatively narrow spectral bands of sufficient intensity forced use to confine our studies for the present to red and blue. This paper reports the results of these studies.