Physiological factors determining formation of plastocyanin and plastidic cytochrome c-553 inScenedesmus

摘要

Physiological conditions necessary for the formation of plastocyanin and the concurrent cessation of cytochrome c-553 formation were studied in cells of copper-deficientScenedesmus acutusafter the addition of copper. Plastocyanin is formed after a lag-phase, leaving constant the content of plastidic cytochrome c-553. Therefore, the concentration of plastocyanin per cell increases and the concentration of cytochrome c-553 decreases during growth. Formation of plastocyanin during the induction period studied is dependent on light intensity. In the dark, there is a 90 inhibition, whereas under light intensities above 50 Wm-2, a ratio of 1.3 molecules plastocyanin per 1,000 molecules chlorophyll is attained.