[Further studies on the variability of the photosynthetic unit]

The concentration of Cytochrome f and P700 in chlorophyll-deficient mutants of Chlorella fusca

The ratio of Chlorophyll: Cytochrome f and of Chlorophyll: P700 (reaction center pigment in photosystem I) is essentially lower in chlorophyll-deficient mutants than in the normal green strain. On a dry weight basis, the mutants have the same or a higher content of redox enzymes than the normal form. The size of the photosynthetic unit of the mutants is 4 to 7 times smaller than that of the normal strains, due mainly to a deficiency of the light-harvesting chlorophyll-protein complex.

[The dependence of the concentration of plastid quinones and pigments in Zea mays and Atriplex rosea on the light intensity and the age of the plants]

The concentration of lipophilic plastid quinones (plastoquinone, plastoquinol, α-tocopherol, α-tocoquinone) in the C4-plants Zea mays and Atriplex rosea is lower than in the already studied C3-plants.In Zea mays the concentration of plastid quinones increases only a little with the age of the plant and then decreases again, while the concentration of quinones in Atriplex rosea constantly rises during the whole test period of 10 weeks.The ratio of chlorophyll a:b is 3,5 in Zea mays and 3,6 in Atriplex rosea.The data lead to the supposition that the concentration of photosystem-II-components is lower than the concentration of photosystem-I-components. We assume that especially in the bundle sheath chloroplasts there is a lack of quinones. In the case of Zea mays this could be the reason for the low system-II-activity which has been found by Anderson et al. (1971).