富山湾深層水を用いた紅藻ミリンSolieria pacifica の成長と体色改善(Growth and Improvement of Thallus Color of a Red Alga Solieria pacifica Cultured in Toyama Bay Deep Seawater)
- 標題
- 富山湾深層水を用いた紅藻ミリンSolieria pacifica の成長と体色改善(Growth and Improvement of Thallus Color of a Red Alga Solieria pacifica Cultured in Toyama Bay Deep Seawater)
- 作者
- 小林美樹・小川晃弘・熊谷敬之・藤田大介(Miki Kobayshi, Akihiro Ogawa, Takayuki Kumagai and Daisuke Fujita)
- 文件屬性
- 日本研究
- 知識分類
- 水產養殖
- 出版年
- 2013
- 刊名
- 海洋深層水研究
- 卷
- 14
- 期
- 1
- 頁
- P27-33
- 點閱數
- 2628
摘要
ミリンSoll'erl'a Pac加caは南日本で採取されている食用の肉質の紅藻である． 千葉県館山産ミリ ンを富山県入善町で取水・加温した海洋深層水（14oC）を用いて藻体939を流水培養した結果， 極めて成長が良く130 日目には24585 9 (26倍）となった． また，館山市の生育地ではミリン藻体 が春から夏にかけて黄化したが，深層水培養藻体は紅色に保たれた． そこで，黄化の原因を探るた め，4種（窒素無添加，リン無添加，窒素・リ ン無添加および窒素・リン1/10濃度添加）の栄養 添加海水（Grund 改変培養液）で培養した結果，窒素無添加区のみで黄化が認められ，紅色の維持 に窒素が不可欠であることが明らかになった． 黄化藻体では，色彩色差計のL＊値の増加とa’値の 減少，藻体中のクロロフィルαおよびフイコエリスリンの減少が認められた． 加温深層水はミリン の生産の増大のみならず体色の改善にも役立つことが示された．
Solieria pacifica is a warm temperate red alga with fleshy thalli, harvested in southern Japan. When this alga was cultured in a tank (100 1 in volume) with running Toyama Bay deep seawater (DSW) warmed up to 14C after pipelined from a depth of 397 m at Nyuuzen, a 26-fold in fresh weight was obtained in 130 days. During culture in DSW, thallus color of S. pacifica was kept red while wild thalli in nature turned yellow from late spring to summer. To examine the factor responsible for red color retention, further culture experiment was designed using four types of enriched seawater: modified Grund Media without NaNO3 (MGM-N), without Na2HPO4・ 12H20 (MGM-P), without NaNO3 and Na2HPO4・12H20 (MGM-NP）and with 1/10 concentrations of NaNO3 and Na2HPO4・12H20 (MGM*1/1ONP). Yellowed thalli (ca. 12 g/thaflus) were cultured in separate flasks (300 ml in volume, n=3/medium, weekly exchange of medium) in an incubator with the following conditions: 20セ，14L:1OD and 30-40 umol photons m-2 s-' for 34 days. Thallus color was evaluated with the naked-eye, measurement of L* a* b* values using colorimeter (CR-400, Konica Minolta) and quantification of chlorophyll a (Chl a) and phycoerythrin (PE) using photospectrometer (U-3310, Hitachi). Results showed thalli turned yellow in MGM-N after 28 days but kept more or less deepened red in MGM-P, MGM-NP and MGM*1/1ONP. These color changes were supported by the increase of L* value (lightness) as well as decrease of a* value (degree of redness). Chl a and PE significantly increased with MGM-P (and MGM*1/1ONP in PE) but decreased with MGM-N and MGM-NP, showing that the presence of nitrogen improved thallus color. Warmed DSW will be an ideal tool not only to enhance the stock but also to keep or improve the thallus color of Solieria pacifica.
Solieria pacifica is a warm temperate red alga with fleshy thalli, harvested in southern Japan. When this alga was cultured in a tank (100 1 in volume) with running Toyama Bay deep seawater (DSW) warmed up to 14C after pipelined from a depth of 397 m at Nyuuzen, a 26-fold in fresh weight was obtained in 130 days. During culture in DSW, thallus color of S. pacifica was kept red while wild thalli in nature turned yellow from late spring to summer. To examine the factor responsible for red color retention, further culture experiment was designed using four types of enriched seawater: modified Grund Media without NaNO3 (MGM-N), without Na2HPO4・ 12H20 (MGM-P), without NaNO3 and Na2HPO4・12H20 (MGM-NP）and with 1/10 concentrations of NaNO3 and Na2HPO4・12H20 (MGM*1/1ONP). Yellowed thalli (ca. 12 g/thaflus) were cultured in separate flasks (300 ml in volume, n=3/medium, weekly exchange of medium) in an incubator with the following conditions: 20セ，14L:1OD and 30-40 umol photons m-2 s-' for 34 days. Thallus color was evaluated with the naked-eye, measurement of L* a* b* values using colorimeter (CR-400, Konica Minolta) and quantification of chlorophyll a (Chl a) and phycoerythrin (PE) using photospectrometer (U-3310, Hitachi). Results showed thalli turned yellow in MGM-N after 28 days but kept more or less deepened red in MGM-P, MGM-NP and MGM*1/1ONP. These color changes were supported by the increase of L* value (lightness) as well as decrease of a* value (degree of redness). Chl a and PE significantly increased with MGM-P (and MGM*1/1ONP in PE) but decreased with MGM-N and MGM-NP, showing that the presence of nitrogen improved thallus color. Warmed DSW will be an ideal tool not only to enhance the stock but also to keep or improve the thallus color of Solieria pacifica.