Title: Chemical composition of Skeletonema costatum (Grev.) Cleve And Pavlova (monochrysis) Lutheri (droop) green as a function of nitrate-, phosphate-, and iron-limited growth
Abstract: The variation in chemical composition of Skeletonema costatum (Grev.) Cleve and Pavlova lutheri (Droop) Green was studied in batch cultures with N-, P-, and Fe-deficient media under continuous light. In vivo fluorescence, chlorophyll a, ATP, cellular nitrogen, carbon, and phosphorus, and cell density were measured. The exponential growth rate was 2.9–3.5 doubl, day−1 for Skeletonema and 1.2–1.9 doubl, day−1 for Pavlova, with the lower rates pertaining to cultures in Fe-deficient media. In exponentially growing cultures nitrogen and carbon per cell increased with an increasing N/P ratio of the media, whereas chlorophyll a, ATP, and organic phosphorus per cell remained relatively constant. In Fe-deficient cells nitrogen and carbon per cell was high, as for cells in media with a high N/P ratio. The total variation in exponential cells was contained within a factor of three. Larger differences in chemical composition were found between exponentially growing cells and nutrient deficient cells. For all types of nutrient deficiency the chl/N and chl/C ratios decreased when cells went from the exponential phase to the starvation phase. The ratio between in vivo fluorescence and chlorophyll a increased 4–5 fold. The CN ratio (atomic) of both species increased from 5–7.5 for exponentially growing cells up to 35 during N-deficiency and up to 13 during P-deficiency. For cells in Fedeficient medium values were scattered in the 7–11 range. ATP and organic phosphorus followed each other closely and had values which were about three times higher in Skeletonema than in Pavlova when using any other parameter as a frame of reference for identical media and growth stages. In N-deficient media the NATP ratio was virtually the same for exponentially growing cells and starved cells. The CATP ratio reached high levels in nutrient deficient cells, with a maximum of 9000 for P-deficient cells of Pavlova. Both species had a minimum value of polyphosphates corresponding to ≈ 10 % of the total phosphorus. In P-rich media Pavlova had storage polyphosphates up to 70 % of the total P. Storage polyphosphates were not observed in Skeletonema. With the set of factors used it is possible to identify growth stages and type of nutrient deficiency for a given culture. It is indicated that, with certain limitations, this approach may be applicable in field studies.
Publication Year: 1977
Publication Date: 1977-09-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 205
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