Changes in Chlorophyll a/b Ratio and Products of 14CO2 Fixation by Algae Grown in Blue or Red Light

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Abstract
Chlamydomonas FC. reinhardtii Danegeard (-) (No. 90)] and Chlorella \C. pyrenoidosa Chick (Emerson) (No. 395)] were grown for 10 days in white light, 955 [mu]w/cm2 blue light (400-500 m[mu]) or 685 [mu]w/cm2 red light (above 600 m[mu]). Rates of growth in blue or red light were initially slow, but increased over a period of 5 days until normal growth rates were reestablished. During this adaptation period in blue light, t otal 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 the chlorophyll a/b ratio. After adaptation to growth in blue light and upon exposure to 14c with either blue or white light for 3 to 10 minutes 30 to 36% of the total soluble fixed 14c 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 algae in red light, 14c accumulated in malate, aspartate, glutamate and alanine, whereas glycolate contained less than 3% of the soluble l4c fraction.