水槽中で培養したマコンブ胞子体の子嚢斑形成と生長にお よぼす水温及び光周期の影響

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1 水槽中で培養したマコンブ胞子体の子嚢斑形成と生長にお よぼす水温及び光周期の影響 誌名 水産増殖 = The aquiculture ISSN 77 著者 巻 / 号 桐原, 慎二藤川, 義一能登谷, 正浩 巻 号 掲載ページ p. 8-9 発行年月 年 月 農林水産省農林水産技術会議事務局筑波産学連携支援センター Tsukuba Business-Academia Cooperation Support Center, Agriculture, Forestry and Fisheries Research Council Secretariat

2 SUISANZOSHOKU8 9 9 Effect of Temperature and Day Length on the Zoosporangial Sorus Formation and Growth of Sporophytes Laminaria japonica Areschoug (Laminariales, Phaeophyceae) in Tank Culture Shinji KIRIHARA, Yoshikazu FUJIKAWA, and Masahiro NOTOYA Abstract: In order to obtain mature sporophytes of Laminaria japonica for seeding, effect of seawater temperature (,,,, ) and day length ( : 9, :, 9 : h LD) on the growth and zoosporangial sorus formation were investigated in litres culture tank with flowing filtered seawater, and compare with natural seawater temperature and day length as a control experiment. The sporophytes could not survive at. At -, the sporophytes died early with increasing higher temperature or shorter day length. Many sporophytes produced a zoosporangial sorus at - and 9 D : L in a short culture period. Zoosporangial sorus was produced earlier more than three weeks at - and 9 L : D and at and L : D in contrast to control experiment tank. We can get mature sporophytes within a month from natural young st year sporophytes under these culture conditions. It is considered that the suitable conditions for the growth and maturation of sporophytes are at lower temperature in the long day conditions. Key words: Laminaria japonica; Zoosporangial sorus formation; Mature condition; Sporophyte Laminaria japonica Areschoug ) ) -) L. saccharina Costaria costata Undaria pinnatifida U. undarioides ) 7) 8-) Aomori Prefectural Fisheries Research Center, Aquaculture Institut Moura, Hiranai, Aomori 9-8, Japan Aomori Prefectural Fisheries Promotion Division, -87, Japan Aomori Tokyo University of Fisheries, Konan, Minato, -877, Tokyo Japan 8

3 88 cm.7 cm 998 cm mm. t l E/m /s W hr L : 9hr D hr L : hr D 9hr L : hr D ) Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar Fig.. Changes of the natural sea water temperature () Fig. and day length (-) in the culture tank of sporophyte of 8 Laminaria japonica. Arrows show the date of zoosporangial sorus 8. formation Fig. 8 cm cm Fig. Fig.. Formation of zoosporangial sorus on five sporophytes of Laminaria japonica at the natural day.7 length and filterd seawater., unformed zoospo - rangial sorus;, formed zoosporangial sorus on the.8 reverse side of the sporophyte;, formed zoosporan - 7 gial sorus on both surface of sporophyte. Temperature (ºC) Individuals Days Day length (hr)

4 Individuals ºC ºC ºC ºC ºC hr L: 9hr D hr L: hr D 9hr L: hr D Days Fig.. Formation of zoosporangial sorus on the sporophyte of Laminaria japonica at various temperatures and day length., unformed zoosporangial sorus;, formed zoosporangial sorus on the reverse side of sporophyte;, formed zoosporangial sorus on both surface of sporophyte

5 8 89 Fig. C-E 8 Fig. F 999 Fig. A 8 Fig. 997 Fig..8 cm.8 cm.8 cm.. cm. cm. cm 7. cm. cm. cm 8. cm. cm. cm.9 cm. cm Fig.. Formation of zoosporangial sorus on the sporophyte of Laminaria japonica at various temperatures of (A), (C), (D) and (E) under a day length of 9 L : D after 8 days, and at under a day length of 9 L : D after 8 days (B), and natural day length and seawater temperature (control) (F). Bar shows cm. Growth (cm) hr L:9hr D hr L:hr D 9hr L:hr D Control Days Fig.. Growth of the sporophyte of Laminaria japonica at various temperatures and day lengths, and natural day length and seawater temperature (control)., ;, ;, ;, ;, ; Vertical bar, standard deviation.

6 ) ) ) 7) ) 9 ) ) 9 l Mizuta et al. 7), : 9, 7 cm cm 8mol/m /s 8 7 hr L : 8hr D hr L : hr D 8hr hr D L : 8,9) cm cm :, 9 : h LD

7 : pp Laminaria japonica Areschoug pp () - 9() -7 9 pp , - pp. zoosporangia on the thalli of Undaria pinnatifida and Costaria costata in culture. Bull. Hokkaido Reg. Fish Res. Lab.,, -8. 7() 997 : 7pp. - () () pp Mizuta, H., K. Nimura, and H. Yamamoto (999): 8Nimura, K. and H. Mizuta (): Inducible effects of Inducible condition for sorus formation of the sporophyte abscisic acid on sporophyte of Laminaria japonica discs of Laminaria japonica Areschoug (Phaeophyceae). Areschoug (Laminariales, Phaeophyceae). J. appl. Fisheries Sci., (), -8. Phycol., (), Lüning, K. (988): Photoperiodic control of sorus 9Lüning, K., A. Wagner, and C. Buchholtz (): formation in the brown algae Laminaria saccharina. Mar. Evidence for inhibitors of sporangium formation in Ecol. Prog. Ser.,, 7-. Laminaria digitata (Phaeophyceae) during the season of 9 Sanbonsuga, Y. and Y. Hasegawa (99): Studies on rapid growth. J. Phycol.,, 9-. Laminariales in culture. II. Effects of culture condition on 99 the zoosporangium formation in Costaria costata (Turn.) Saunders. Bull. Hokkaido Reg. Fish Res. Lab.,, () - Sanbonsuga, Y. and Y. Hasegawa (97): Studies on Laminariales in culture. I. On the formation of