Effect of photoadaptation on the specific growth rate and carbon to chlorophyll a ratio in diatoms Phaeodactylum tricornutum

The change of growth rate and the chlorophyll content has been investigated during the transfer of two cultures Phaeodactylum tricornutum (Bohlin, 1897), previously adapted to high and low light, into the light of varying intensity. The calculation of the specific growth rate of algae in the experiment was performed on a gain of the carbon in the sample; carbon content was determined by optical density of the cell suspension at 750 nm; the concentration of chlorophyll a was measured by fluorimetric method. The period of adaptive changes of chlorophyll concentration finishes for 2 days and is independent of light conditions of adaptation in the light range of 16 to 430 mkE.m^sup -2^.s^sup -1^. At extremely high light (900 and 1250 mkE.m^sup -2^.s^sup -1^), the difference in the behavior of cultures in response to the light factor is observed. In the shadow culture photoinhibition of growth and increasing C/Chl ratio to 140-250 is observed for 1-2 days.