1989 Fiscal Year Final Research Report Summary
Studies of mechanism of retaining of vegetation in Trapa natans var. japonica in an europhic inland water
| Project/Area Number |
63540513
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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 | Faculty Science, Chiba University |
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Principal Investigator |
IKUSIMA Isao Chiba Univ. Prof., 理学部, 教授 (20009046)
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| Project Period (FY) |
1988 – 1989
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| Keywords | Trapa natans var. japonica / Strategy / buried seed / rosette leaf / eutrophic water / Inba-numa / 印旛沼 / 埋土種子 |
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| Research Abstract |
Trapa natans var. japonica had a high reproductivity and covered almost surface of an eutrophic lake, Inba-numa.
1 Strategy of the seed: The starch seed of the plant is regard as the one of bigger seeds is aquatic macrophytes. The mean fresh weight was 7 g and the maximum weight reached 12 g. The mean economic rate of transformation from seeds to seedlings was 0.47. Large seedlings could produce floating-leaves to 2.2 m of depth in an eutrophyic water. The plant given priority to seed size rather than number as much as half of the normal value of the total insolation hours from August to October.
2 Strategy of the rosette leaf: LAI was less than 2 and a new leaf was constantly kept under good light condition. A new leaf came out every one day on main stem and about 30 leaves made up a rosette for seven month from May. The life span of leaves was as long as 25 days. The rosette produced 3 to 5 well developed and large seeds.
3 Strategy at reproduction processes: Fruits had two types, the one was a floating type or a dispersal type and the other regard a conservative type, the fruit sunk near the mother plant. The buried seed germinated when the water temperature became higher than 10ﾟC and the rate of germination reached 60 % and 92 % in the next year and the year after next year, respectively. The buried seed was prepared all year round.
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Research Products
(6 results)
