| Abstract: | The chloroplast membranes of Gonyaulax polyedra Stein were studied in replicas of rapidly frozen and fractured cells. The thylakoid EFs face lacked the large 15–16 nm particles characteristic of plants with the light-harvesting chlorophyll a/b protein, presumably because the principal light-harvesting protein of Gonyaulax is the small water-soluble peridinin-chlorophyll-protein and the chlorophyll a/b protein is absent. As in other plants, the EFs thylakoid fracture face carried more particles (4 ×) than EFuface. The PF faces of the thylakoid showed twice as many particles as did the EFs faces. No circadian differences in the number or size of thylakoid membrane particles could be detected. Three membranes comprise the chloroplast envelope in Gonyaulax. They could be clearly differentiated in freeze-fractured cells. The middle envelope membrane carried many fewer particles on both the EF and PF faces than did the other two envelope membranes. The PF faces of both the outer and inner envelope membranes showed more particles than the EF faces, as do many other membranes which have been examined. |
