SPECTRAL PROPERTIES OF CHLOROPLAST MEMBRANES AS A FUNCTION OF PHYSIOLOGICAL TEMPERATURES

The absorption spectrum of chloroplasts changes as a function of temperature. As chloroplasts are cooled from room temperature to 10°C there are increases in absorption at 675, 500 and 436 nm, plus a small decrease at 685 nm. As the chloroplasts are heated to 34°C there are decreases in absorption at 675, 500 and 436 nm plus increases in absorption at 690 and 400 nm. It is concluded that the temperature dependent change in phase of the membrane lipids (solid to liquid crystal state) modifies the state of chlorophyll aggregation. © 1979.