The Dependence of Cell Division in Chlorella on Temperature and Light Intensity

The effects of temperature and light on cell division were studied in synchronized suspensions of the high‐temperature strain Chlorella 7–11–05. It was found that the time for incipient cell division, the progress in the process after it started, and the number of cells produced are influenced by temperature and light intensity. Within limits, cell division is generally favored by the increase in temperature. The increase in light intensity first favors cell division then, after the optimal light intensity is attained, a further increase in light intensity inhibits cell division. Observations are discussed in connection with the findings of other investigators. The limitations of cell division by temperature and light intensity are considered to be separate from the effects of these factors on growth.