RESTING CELLS OF PEDIASTRUM

D avis , J oseph S. (Southern Illinois U., Edwardsville.) Resting cells of Pediastrum. Amer. Jour. Bot. 49(5): 478–481. Illus. 1962.—After approximately 10 weeks in a partially defined mineral medium, cells of vegetative colonies of Pediastrum boryanum lost their chlorophyll and became orange resting cells. The resting cells were colored orange by carotenoid pigment dissolved in fat droplets within the cells. No cell wall thickening occurred during or after resting‐cell formation. Starch was abundant in the resting cells. Dried resting cells remained viable for at least 4 years. When placed in the culture medium, 4‐year‐old dried resting cells became green and reproduced like vegetative cells.