1989 Fiscal Year Final Research Report Summary
Kinetic analyses of allelopathic phenomena between microalage and environmental utilization of active substances
| Project/Area Number |
62540498
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
生態学
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| Research Institution | Shimane University |
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Principal Investigator |
MOCHIDA Kazuo Shimane Univ. Fac. of Agriculture Associate Professor, 農学部, 助教授 (30032577)
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| Co-Investigator(Kenkyū-buntansha) |
OZOE Yoshihisa Shimane Univ. Fac. of Agriculture Associate Professor, 農学部, 助教授 (80112118)
NAKAMURA Toshiie Shimane Univ. Fac. of Agriculture Professor, 農学部, 教授 (80155845)
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| Project Period (FY) |
1987 – 1989
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| Keywords | Microalage / Allelopathy / Growth-curve equation / Growth inhibitor / Diatom / Kinetics |
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| Research Abstract |
Allelopathic phenomena between microalage were examined using the dominant species of phytoplankton isolated from the brackish lake Nakanoumi.
1. Interaction between dominant algae. The interactions between 2 species among 7 species of the algae were classified to 5 types. Especially, it was strongly suggested that the growth-inhibitory effect caused by Cymbella sp. was an allelopathic phenomenon which was attributable to the inhibitors secreted from the cells.
2. Kinetic evaluation of interaction between algae. For analyzing kinetically the interactions between algae, two kinds of new type equations which were named the expanded logistic equation and the expanded Lotka-Volterra equation were derived. The former was used to express extensively the algal growth process during whole period including the decay or death phase. The latter was used to evaluate the degree of interaction between algae and thereby to quantify the degree as the interaction coefficients. Cymbella sp. was selected again as the most appropriate alga for pursuing the growth inhibitors.
3. Separation and properties of growth inhibitors. Growth inhibitors produced by Cymbella sp. were found not only in the culture filtrate but also in the cell extracts. From the extract with 10 % acetone aqueous solution, 2 active fractions were separated by gel filtration using Bio-Gel P-2 and they were considered to be polar substances which the molecular weight was about 200. Their thermostability, ph-stability, and inhibitory effects on 4 species of the other algae were also confirmed. However, the structure identification and the environmental utilization of active chemicals were remained as further themes to be examined.
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Research Products
(4 results)
