On the Influence of Environmental Factors on Growth of Conchocelis and the Change in pH of Culture Sea Water

The ecological studies of the Conchocelis-phase of Porphyra have been reported by many authors. The present investigation was carried on concerning the environmental factors such as light intensity, chlorinity, culture solution and pH which affected the early development of carpospores. The pH changes of culture solution were also observed experimentally. The results obtained may be summarized as follows: The fittest light intensity varies with the temperature and it is 4000 lux at 10～15℃ water temperature and 2000 lux at 20℃. On the influece of chlorinity, the results were essentially similar to the facts shown by many other investigators. The Conchocelis grows better at lower pH value about 7.3 than the normal sea water pH 8.2. When the grown Conchocelis is cultured in the light, the pH of culture solution rises above 9. By this increase in alkalinity the lime deposit on the shell which is called "samehada", seems to be produced as a sort of CaCO₃