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Satomi Takeda, Fumihiko Sato, Yasuyuki Yamada, Photosynthetic Characteristics of Photoautotrophically Cultured Cells of Tobacco, Plant and Cell Physiology, Volume 30, Issue 6, September 1989, Pages 885–891, https://doi.org/10.1093/oxfordjournals.pcp.a077820
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Abstract
The photosynthetic characteristics of photoautotrophically cultured cells of tobacco (Nicotiana tabacum cv. Samsun NN) as well as those of photomixotrophically cultured cells and green leaves were investigated. Analyses revealed that on a fresh weight basis cultured tobacco cells had lower chlorophyll contents than cells of green leaves. The chlorophyll content per chloro-plast, however, was almost the same in both types of cell, and the chloroplast number per cell accounted for only small differences in the cellular chlorophyll content. This indicates that the larger cell volume of cultured cells is the main factor in the difference in the chlorophyll content of these cells.
Photosynthetic activity measurements also showed differences in the chloroplasts of cultured and leaf cells. The maximum activities of photosystem I and the Hill reaction for the cultured cells were about half those for leaf cells on a per unit chlorophyll basis. Moreover, photo-autotrophic cells had relatively constant photosystem I and Hill reaction activities during growth; whereas, on a fresh weight basis these activities in leaf cells reflected developmental changes in the chlorophyll content.
Lithium dodecyl sulfate-polyacrylamide gel electrophoresis showed qualitatively similar thylakoid polypeptide compositions for cultured and leaf cells at all stages of growth even though there were quantitative decreases in the contents of several polypeptides in the cultured green cells (especially in photomixotrophic cells) in comparison to the polypeptide contents of tobacco leaves. We speculate that the lower photosynthetic activity of the cultured cells may be caused by this reduction in the contents of certain thylakoid polypeptides.
