Mitochondrial number and form change during autospore formation in Chlorococcum infusionum (Schrank) Meneghini (Chlorococcales, Chlorophyta)

Abstract

Abstract Three dimensional form changes of mitochondria during the autospore formation of Chlorococcum infusionum are followed with the electron microscope. In the youngest cells, five ovoid mitochondria are seen. In mature cells, nuclei divide successively three or four times without being accompanied by cell division. During this period, mitochondria multiply to about 20. Shortly before septum formation, mitochondria fuse with each other to form a reticular and branched mitochondrion. Later, the reticular mitochondrion is divided by growing septa, thus being distributed in the autospore. In cells liberated from mother cell walls, the mitochondrion is fragmented into several ovoid pieces. These mitochondrial form changes are discussed in comparison with those reported in other organisms.