Changes in Chlorophyll a/b Ratio and Products of '4C02 Fixation

Sutmmary. Chlamydomonas and Chlorella were grown for 10 davs in white light. 955 Uw/cm2 blue light (400-500 m,u) or 685 Juw/cm2 red light (above 600 mb). Rates of growth in blue or red light were initially slow, but increased over a period of days until normal growth rates were reestablished. During this adaptation period in blue light, total chlorophyll per volume of algae increased 20 % while the chlorophyll a/b ratio decreased. In red light no change was observed in the total amount of chlorophyll or in t'he chlorophyll a/tb ratio. After adaptation to growth in blue light and upon exposure to "CO, with either blue or white light for 3 to 10 minutes, 30 to 36 % of the total soluble fixed 1"C accumulated in glycolate-14C which was the major product. However, with 1 minute experiments, it was shown that phosphate esters of the photosynthetic carbon cycle were labeled before the glycolate. Glycolate accumulation by algae 'grown in blue light occurred even at low light intensity. After growth of the al,gae in red light, 1"C accumulated in malate, aspartate, glutamate and alanine, wherea; glycolate contained less than 3 % of the soluble 14C fraction.