EFFECTS OF GLUCOSE ON THE PROCESS OF CHLOROPLAST DEVELOPMENT IN CHLORELLA PROTOTHECOIDES1

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Abstract
By growing Chlorella protothecoides in a medium rich in glucose and poor in nitrogen source (urea), the entirely chlorophyll-less cells showing no discernible plastid structure and containing only little RNA and protein were obtained. These cells, which were called “glucosebleached” cells, turned green after a certain lag period, when they were incubated, in the light, in a medium containing the nitrogen source and basal mineral nutrients but without glucose. As has been shown in previous studies, this greening process involves two consecutive steps : a light-independent phase, in which RNA plays an essential role, and a light-requiring phase, in which the chlorophyll formation and full organization of chloroplast take place accompanied by the formation of a certain species of protein (“alkali-stable” protein). The whole process of greening was found to be profoundly suppressed by addition of glucose, the degree of suppression being determined by the relative concentrations of glucose and the nitrogen source. The primary act of glucose was manifest in the repression of syntheses of RNA, and of the species of protein mentioned above, which participate in, or causally related to, the first and second phases, respectively, in the greening process.