Growth Rate of Chlorella in Flashing Light.

An apparatus is described for precise measurement of growth rate of an alga as a function of intensity and intermittency of illumination. Dilution of a culture is controlled by a photometric device to just such a rate as will maintain constant density of population and balance the growth rate. Maintenance of constant volume by an automatic siphon allows direct application of the differential form of the growth equation in evaluating specific growth rate. The relationships of the new apparatus to other steady-state growth devices are discussed. Grateful acknowledgment is made to the Carnegie Institution of Washington for aid received by the junior author as a Visiting Investigator in its Department of Plant Biology.