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Photosynthesis and carbon metabolism in photoautotrophic cell suspensions of Chenopodium rubrum from different phases of batch growth
Author(s) -
Hüsemann Wolfgang,
Herzbeck Hildegard,
Robenek Horst
Publication year - 1984
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.1399-3054.1984.tb04585.x
Subject(s) - carbon fixation , photosynthesis , ribulose , biochemistry , starch , biology , rubisco , chlorophyll , pyruvate carboxylase , respiration , dehydrogenase , enzyme , botany
Rapidly dividing photoautotrophic cell suspensions from Chenopodium rubrum L. assimilated about 85 μmol CO 2 (mg chlorophyll) −1 h −1 . During the late stationary phase of culture growth, CO 2 fixation rate was reduced to about 60 μmol CO 2 (mg chlorophyll) −1 h −1 . Actively dividing cells characteristically incorporated a smaller proportion of 14 C into starch than cells from non‐dividing stationary phases. In rapidly dividing cells, [ 14 C]‐turnover from free sugars, sugar‐phosphates, organic and amino acids was substantially higher compared to non‐dividing cells from stationary growth phase. Higher proportions of photosynthetically fixed carbon were channelled into proteins, lipids and structural components in actively dividing cells than in non‐dividing cells. In the latter. 14 C was preferentially channeled into starch, and a striking increase in starch accumulation was observed. The transfer of non‐dividing, stationary growth‐phase cells into fresh culture medium resulted in an increase in the maximum extractable activities of some enzymes involved in the glycolytic and dark respiratory pathways and in the citric acid cycle. In contrast, the maximum extractable activities of the chloroplastic enzymes, ribulose‐1,5‐bisphosphate carboxylase (EC 4.1.1.38) and NADP + ‐glyceraldehyde‐3‐phosphate dehydrogenase (EC 1.2.1.13) were highest after the cells had reached the stationary growth phase.