Document Type

Thesis - Open Access

Award Date

1983

Degree Name

Master of Science (MS)

Department

Biology

Abstract

The possibility for biological inhibition of blue green algae by allelopathy was investigated in seven replicated laboratory and three replicated lake experiments. Controls containing natural lake water were compared with treatments containing the potentially allelopathic plants Najas guadalupensis, an aquatic monocot, Hydrodictyon reticulatum, a green alga, and a combination of the two plants. Significant changes in chlorophyll a were tested for in all experiments; algal cell count changes were tested for in four experiments. 250-ml glass flasks were used in laboratory experiments, and partially submerged 5-gallon semitransparent polyethylene containers were used in lake experiments. Experiment duration was 5-12 days. Four of the ten experiments had significantly lower treatment means for chlorophyll a than the control -- the Najas treatment was significantly lower three times, the Hydrodictyon treatment was significantly lower two times, and the Najas plus Hydrodictyon treatment was significantly lower once. In the four cell-counted experiments, the Najas plus Hydrodictyon treatment was significantly lower than the control for one or more species of blue green algae in all four experiments. The Najas treatment was significantly lower for one or more species of blue green algae in two experiments, and the Hydrodictyon treatment was significantly lower for one or more species of blue green algae in two experiments. It appeared that both Najas and Hydrodictyon individually had the potential to inhibit blue green algae some of the time, although the combination of the two resulted in the greatest inhibition. The inhibition was probably due to an allelopathic substance, although its nature was not determined.

Library of Congress Subject Headings

Freshwater algae

Allelopathy

Algae -- Control

Freshwater algae -- South Dakota

Algae -- Control -- South Dakota

South Dakota State University Theses

Format

application/pdf

Number of Pages

57

Publisher

South Dakota State University

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