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MORPHOLOGICAL CHANGES IN TOXIC AND NON‐TOXIC MICROCYSTIS ISOLATES AT DIFFERENT IRRADIANCE LEVELS 1
Author(s) -
Krüger G. H. J.,
Eloff J. N.,
Pretorius J. A.
Publication year - 1981
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.1981.tb00818.x
Subject(s) - axenic , biology , microcystis , irradiance , cell size , axenic culture , light intensity , volume (thermodynamics) , botany , cyanobacteria , microbiology and biotechnology , genetics , optics , physics , quantum mechanics , bacteria
Light intensity (4.5–40.0 μEin m −2 s −1 ) and culture age had a pronounced effect on cell size and size range of a non‐toxic axenic Microcystis isolate. The rate of cell volume increase (μm 3 d −1 ) was 1.03 × light intensity (μEin m −2 s −1 ) – 6.49. Average cell volume varied from 33 to 119 μm 3 , cells at higher light intensities being larger and having a larger size range. The effects on a toxic axenic Microcystis isolate were similar but less pronounced. Average cell volume ranged from 21–74 μm 3 . In general, cell size and especially size variability appear to be sensitive indicators of physiological state, with cells under stress conditions being larger and associated with a larger size range. The wide range of cell diameters observed at different irradiance levels (3.4–7.2 μm for the non‐toxic and 1.8–6.4 μm for the toxic isolate), makes questionable the use of cell size as a taxonomic character without careful consideration of environmental conditions.