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Effect of different light qualities on the ultrastructure, thylakoid membrane composition and assimilation metabolism of Chlorella fusca
Author(s) -
Wilhelm Christian,
Krámer Petra,
Wild Aloysius
Publication year - 1985
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1985.tb03353.x
Subject(s) - thylakoid , photosynthesis , chlorophyll , photosystem ii , photosynthetic reaction centre , biophysics , photosystem , biology , chlorophyll b , membrane , chlorella , chlorophyll a , chloroplast , botany , chemistry , biochemistry , algae , gene
Chlorella fusca (Shihira et Krauss) strain C‐1.1.10 was grown under three different light qualities (red, white or blue light) in homocontinuous cultures. Under electron microscopy, blue light cultures showed enlarged cells, thinner cell walls and lower starch content than red light cells. Under blue light, the degree of stacking of the thylakoid membranes was significantly lower than under white or red light conditions. Changing the light from blue to red the ratio of exposed to appressed membranes was doubled. Compared to red light cells, blue light cells exhibited higher photosynthetic rates per chlorophyll molecule and contained less chlorophyll per dry weight. Blue light stimulated the content of soluble protein as well as that of soluble carbohydrates. The dry weight productivity per unit time was enhanced under blue light conditions. The thylakoid protein complexes which are generally assumed to be localized in the exposed membranes were found in higher concentrations under blue light than under red light. In blue light, both the Photosystem II/Photosystem I ratio and the ratio of light‐harvesting chlorophyll protein to P‐700 chlorophyll a ‐protein were lower than in red light. Blue light cells contained twice the concentration of cytochrome f , which correlates well with their higher photosynthetic capacity. When altering the light quality, the degree of change in the reaction center complexes was much lower than expected given the corresponding degree of change in the ratio of exposed to appressed membranes. These results are discussed in light of the question as to whether the variation in the stoichiometry of the laterally distributed complexes can be explained by changes in the degree of stacking alone.