ISSN:
1432-072X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Absorption spectra of a young and an old culture of the diatom Pheodactylum tricornutum were measured in thin layers between two opal glass sheets. The spectra at 24° and at -196°C were replotted to give equal areas from 730–625 mμ to allow direct comparison. At 24°C the spectrum for the difference between the two cultures had a negative component of 18 mμ half width centered at 675 mμ and a positive region of W0.5=26 mμ near 700 mμ. The spectra at -196°C may be somewhat distorted by clumping of the cells during freezing but nevertheless the 16 day culture clearly showed a smaller proportion of Ca “670” to Ca “680”. This older culture has a shoulder due to a 707 mμ component. The difference curve at -196°C shows the decrease of an unsymmetrical band peaking at 669 mμ and an increase at 695 mμ in addition to the 707 mμ component. Due to the possibility of distortion, the presence of an actual component at 695 is doubtful in these particular cultures. The room temperature spectrum in the chloropyhll a region for the 5 day culture can be closely fitted by a single probability curve at 675 mμ having a half-width of 31 mμ. The sum of two components, with widths more reasonable for chlorophylls, also matched the data well enough. These two probability curves, of 22 mμ half width, centered on 669 and 683.2 mμ and had a height ratio, h669/h683 of 1.18. In the 16 day culture the ratio for these bands changed to 1.11 and there was extra absorption around 700 mμ.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00406320
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