| Project/Area Number |
60480013
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
植物形態・分類学
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| Research Institution | Hokkaido University |
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Principal Investigator |
TATEWAKI Masakazu Inst. of Algological Res., Fac. of Science, Hokkaido Univ., 理学部付属海藻研究施設, 教授 (50000881)
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| Project Period (FY) |
1985 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1987: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥4,900,000 (Direct Cost: ¥4,900,000)
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| Keywords | Seaweed / Obligatory epiphyte / Host specificity / Bialgal culture / Morphogenesis / Nutrient uptake / 仮根機能 / 形態形成活性物質 / 着生藻 / 内生藻 / 宿主植物 |
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| Research Abstract |
Many epiphytic seaweeds are growing on or in certain restricted host plants. Why are definitive hosts required-for specific chemical factors of phisical environment? Three selected species have been investigated to gain well understanding of epiphytehost association culturally and ultrastructurally.
1) Kornmannia zostericola commonly found on the seagrass Phyllospadix iwatensis can grow on artificial substrates under both field and laboratory cultures. The axenic cultures between epiphytes and hosts or polypropylene strings show that this alga does not require and chemical factors from the host plant but needs a suitable wave motion for ist normal morphogenesis. K. zostericola is not an obligatory epiphyte with the definitive host.
2) Coilodesme japonica is normally found to grow on a few definitive host plants such as Cystoseira hakodatense. In bialgal cultures between epiphytes and hosts, sexual reproduction seems to be induced only on the host and zygotic germlings produce saccate initials and can develop into new saccate fronds only when rhizoids penetrate the host tissue. This penetrating rhizoid is considered to act the uptake of organic compounds produced by specific host's metabolism as morphogenetic substances. It is xonfirmed that C. japonica is an obligatory epiphyte with the host-specificity.
3) Blastophysa rhizopus is usually found to grow in the tissue of Grateloupia turuturu in nature. In bialgal cultures between this endophyte and various seaweeds, there is found only substrate requirement for this coenocyte lacking a holdfast mechanism. It seems to have limited host plants which are coarser algae, but can penetrate indiscriminately in wounded plants.
In supposed obligate epiphytes such as C. japonica, identification of active organic compounds supplied by the host plant and rhizoid function with the host tissue will be studied successively.
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