Germination of cysts in acetabularia mediterranea.

Techniques for the growth of uniformly reacting populations of cysts of Acetabularia mediterranea and for quantitative measurement of cyst germination have been developed. Cysts of A. mediterranea can be induced to germinated by exposure to the atmosphere. Germination rates are very low in young cysts. They increased during exposure to total darkness. This "maturation of cysts" is found to be completed after a period of 12-15 weeks. Germination rates of cysts that have passed the maturation period exceed 90 percent in continuous white light and 80 percent in darkness. Cysts germinate in less than two days in darkness and less than four days in light. The influence of temperature at a range of 15 degrees C to 25 degrees C on germination kinetics is studied in light and darkness. Germination is accelerated with increasing temperature up to 21 degrees C. At higher temperature germination is delayed in light but the time of germination remains constant in darknesss. Rates of germination are not altered by the influence of temperature in light while in darkness there is a dramatic decrease at temperatures higher than 21 degrees C. From these findings it is concluded that cyst germinationA. mediteranea does not need any light but is influenced by light dependent systems. The influence of light is strongest at elevated temperatures.