1991 Fiscal Year Final Research Report Summary

Underwater afforestation and its proper constituents

Research Project

Project/Area Number	02660199
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	General fisheries
Research Institution	Kyushu University
Principal Investigator	OKUDA Takeo Kyushu Unive., Fac. of Agr., Prof., 農学部, 教授 (80038174)
Co-Investigator(Kenkyū-buntansha)	KAWAGUCHI Shigeo Kyushu Univ., Fac. of Agr., Assist. Prof., 農学部, 助手 (50195054)
Project Period (FY)	1990 – 1991
Keywords	underwater forest / fucaleans / Sargassum horneri / Sargassum filicinum / hybridization / sexuality / periodicity / vegetative reproduction
Research Abstract	Underwater forests provide marine lives with an essential environment. This study focuses on enlargement or creation of such forests with proper fucaleans. Particular attention was paid on Sargassum horneri and S. filicinum. 1. Egg liberation in each of 11 species in northern Kyushu is not periodic, which used to be considered to occur during the spring tides. 2. Fertilized eggs remain on the surface of a receptacle for a certain period, 1 to 4 days depending on species. 3. Five new localities of S. filicinum, once regarded as a rare species, were confirmed in the Seto Inland Sea in this study. Some sites were exclusively vegetated with this alga instead of S. horneri. 4. Though S. horneri used to be strictly dioecious, monoeceous plants were recently reported to be of a rare occurrence. In this study, more such plants were collected in the Seto Inland Sea. 5. Crossing between S. horneri (eggs) and S. filicinum (sperm) has been successful, and fertilized eggs followed the same development as reported in both species, which are the same. 6. Experiments on vegetative reproduction were conducted as one of methods for seedling production. Four species produced young shoots from fragments of basal part.