The growth promoting effect of 2,4-Dichlorophenoxyacetic acid (2,4-D) and 2,4,5-Trichlorophenoxyacetic acid (2,4,5-T) on Microcystis aeruginosa
Microcystis aeruginosa is known widely for the obnoxious nature of its bloom. Problems resulting from blooms of the alga include: death of fish and other aquatic life, clogging of filter systems in water treatment plants, taste and odor problems, and death of cattle and water fowl via extracell...
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Virginia Tech
2014
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| Online Access: | http://hdl.handle.net/10919/43824 http://scholar.lib.vt.edu/theses/available/etd-07212010-020120/ |
| Summary: | Microcystis aeruginosa is known widely for the
obnoxious nature of its bloom. Problems resulting from
blooms of the alga include: death of fish and other aquatic
life, clogging of filter systems in water treatment plants,
taste and odor problems, and death of cattle and water
fowl via extracellular polypeptides. Blooms of this nuisance
alga have historically occurred in waters receiving
pollution from sewage effluents or runoff from agricultural
lands.
Studies have shown that 2,4-0ichlorophenoxyacetic
acid (2,4-0) and 2,4,5-Trichlorophenoxyacetic acid (2,4,S-T)
mimic the metabolic activities of the plant hormone indoleacetic
Acid (IAA). IAA has been shown to stimulate the
growth of some green and blue-green algae.
Recent evidence suggests that blooms of Microcystis
aeruginosa were triggered when the herbicides 2,4-D and
2,4,5-T were introduced to lakes and rivers.
The results of this study showed that batch cultures
of non-axenic Microcystis aeruginosa containing
2,4-D and 2,4,5-T exhibited significantly more growth than
controls over a wide range of herbicide concentrations.
Growth in 2,4-D treated cells was statistically significant
from the control at a = 0.05 at concentrations as low
as 10 -7 M (0.020 mg/l) and 10 -5M (2.5 mg/l) for 2,4,5-T.
Also, a plot of maximum cell yield values versus herbicide
concentrations resulted in a linear relationship. === Master of Science |
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