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Comparison of Dry Matter Synthesis and Photosynthetic Characteristics of Chlorophyllous and Non-chlorophyllous Cell Suspension Cultures of Soybean (Glycine max. L.)

1982; Elsevier BV; Volume: 105; Issue: 5 Linguagem: Inglês

10.1016/s0044-328x(82)80042-1

0044-328X

Yvonne M. de Klerk‐Kiebert, Tarcies J. A. Kneppers, Peter A.H.M. Barker, H.H. Schalk,

Algal biology and biofuel production

Summary Non-chlorophyllous (white) soybean (Glycine max. L.) cells in batch culture, showed chloroplast biogenesis (greening cells) when grown under continuous illumination. The structural development of these chloroplasts was studied by electron microscopy. Green cell suspensions were obtained by subculturing several times in continuous light. After 4–5 days of culture in the light the chlorophyll content of greening cells had become similar to that of green cells. Photosynthetic characteristics have been determined in intact green and greening cells and in isolated chloroplasts. Intact green cells proved to be able to perform light-dependent O2-production, while the white and greening cells were not. In chloroplasts isolated from green cells photosystem I + II activity could be demonstrated using ferricyanide as electron acceptor and light-dependent, DCMU-inhibitable ATP-synthesis occured. In chloroplasts from greening cells, however, photosystem I + II activity could only be detected from the third day of culture in the light. Although development of photosystem I + II activity in greening cells has been demonstrated with isolated chloroplasts, light-dependent (O2-production by greening cells was never observed. Apparently subculturing more than once under continuous illumination of cells from the greening cultures is necessary to establish this photosynthetic activity. White and green cells fixed equal amounts of CO2 in the light. However, CO2-fixation by green cells was lower in the dark and could be inhibited by addition of DCMU, while CO2-fixation in the white ones was not affected by these treatments. Dry matter synthesis in the white, greening and green cell suspensions was comparable. Apparently the presence of chloroplasts gave the cells no noticeable advantage over white cells. Most likely photosynthetic activity is present in green soybean cells, but the observed values of light-dependent O2-production and CO2-fixation by green cells were too low for photoautotrophic growth.