| 中文摘要 |
本計畫工作的主要內容包括：1. 頭髮菜Bangia atropurpurea、紫菜Porphyra angusta、蜈蚣藻Grateloupia taiwanensis、海膜Halymenia ceylanica等可食性絲狀體的成長在不同溫度、光照、光週、鹽度等環境條件下的適性與差異，藉以1.篩選適合藻種、2.建立固碳效果較佳海藻保種技術、3.推廣較佳固碳效果藻類產業利用及開發。在這四種藻類絲狀體中紫菜和頭髮菜都是果孢子發芽而成的雙套孢子體，而蜈蚣藻與海膜則是源自髓部組織的絲狀體提體培養馴化而成，其各自有不同之生長季節，結果發覺這四種藻類在20~25℃下的生長都是最好，而且都不耐30℃以上的溫度條件生長，且蜈蚣藻與海膜相對的要比紫菜和頭髮菜生長好；另外頭髮菜在30℃下相對於其他種藻類絲狀體較具有耐受性，而蜈蚣藻則在15℃下也能生長。在適合的溫度下，只要光線不是太強(＜9,000 Lux)，光照時間越多生長越好，不同種類間有稍許適應上的差異，鹽度則端看其是否為廣鹽性種類，頭髮菜及蜈蚣藻屬廣鹽性種類，在15‰下還能夠正常生長；2.另研究棲狀褐茸藻Hincksia mitchelliae在不同光強度與氮營養鹽濃度下的成長與藻色素的變化，以評估其作為商業開發藻褐素生產之可行性。結果在實驗所測試的硝酸氮濃度(0~2.4 mM)範圍內，十八天內並未發現到生長有顯著性影響，各色素與葉綠素間比值同樣也不受到影響。然而在較高光強度下棲狀褐茸藻平均日增重率較高，其藻體內葉綠素a與藻褐素的含量變少，但藻褐素與葉綠素a含量比值隨著光強度的提升而增高。推測藻褐素在棲狀褐茸藻體內所扮演的角色，除了做為光合作用的吸光輔助色素，也可能與光保護機制有關。棲狀褐茸藻在低密度(1 g/1.6L)培養時，予以低照度6,000 Lux，維持較好的生長；但在高密度(10 g/1.6L)培養時，則予以較高光強度20,000 Lux，並充分供應硝酸營養鹽，有最佳生長，而隨著藻細胞密度增加，照度減少，可提升藻褐素含量；3. 引進沖繩海蘊Cladosiphon okamuranus，建立藻株培養及保種，控制各世代個體的活存及4. 分別分析其固碳效率，結果如下: 頭髮菜、紫菜生長慢，最後收穫之密度低，其固碳效率分別為7.8及16.34 mg/L/D, 而蜈蚣藻和海膜則較高，分別為34.34, 25.45 mg/L/D, 棲狀褐茸藻也有不錯的固碳效率與快速生長的紅藻絲狀體略同，達33.24，但24 hr連續照光的藻培養只有26.04 mg/L/D，很顯見在固碳效率上，遠低於單細胞微藻(100倍)。 |
| 英文摘要 |
There are four major topics of this project: 1. to identify the optimal growth conditions of the parameters, such as temperature, salinity, light intensity and light period for the culture of the Conchocelis phase of Bangia atropurpurea and Porphyra angusta and the tissue filaments isolated from the pith Grateloupia taiwanensis and Halymenia ceylanica, some of the edible red seaweed species common in Taiwan and determine the best species fit the development of algal aquaculture industry; 2. to identify the effects of light intensity and nitrogen nutrient enrichment on the growth and algal pigment compositions of Hincksia mitchelliae in order to evaluate the possible industrial production of fucoxanthin or the source material in Taiwan; 3. to import the Okinawa mozuku, Cladosiphon okamuranus and learn to control the development of various phases in its life cycle, and eventually develop its industrial production; 4. to compare the carbon fixation rates of these species under study. Among the above mentioned filamentous culture four edible red algal species, we found the environmental preferences of these four algae can be divided into two categories according to their origin of Conchocelis phase or filament tissue. All of these four species preferred the temperature of 20~25℃ but Grateloupia and Halymenia had better performance. It was also noted that Bangia survived better than the other three species at temperature above 30℃. More surprisingly Grateloupia also tolerates the low temperature, as 15℃in contrast to Bangia. Generally, under optimal temperature and not too high intensity of light, such as ＜9,000 Lux, the longer illumination means better growth to all species tested. Different species had slight difference in response to the light. Euryhaline species, such as Grateloupia and Bangia that can grow at 15‰ as normal as in natural seawater, in contrast to Halymenia and Porphyra. Regarding Hincksia mitchelliae, it was found that its growth was significantly affected by the light illumination, stronger the light intensity, higher the average weight gain. Both fucoxanthin and chlorophyll a contents decrease accordingly to the increase of light intensity, but the ratio of fucoxanthin to chlorophyll a increased along with the increasing of light intensity. We also observed that there were no significant difference in growth performance, neither the ratio of carotenoids to chlorophyll a of the alga under the treatment of various nitrate concentration (0~) in a period of eighteen days. It was speculated that fucoxanthin play a role in Hincksia, a photosynthetic accessory pigment but also an antioxidant in preventing the light stress. Spores released from the Cladosiphon okamuranus thalli which the live specimen was collected from Ryukyu have been isolated and cultured for the observation of the various phases in its life cycle. Currently several flasks of the spore and germinated filaments are maintain in the lab for further studies relating the growth requirements. In addition, carbon contents of the above mentioned filaments of the fast growing specimen have been analyzed and calculated for their carbon fixation rates. The slow growing filaments of Porphyra and Bangia which has the least crop harvested has the lowest carbon fixation rate, 7.8 and 16.34 mg/L/day respectively, instead, Grateloupia and Halymenia showed a higher growth rate and rich harvest had higher carbon fixation rates, 34.34 and 25.45 mg/L/day, respectively. Hincksia has a good carbon fixation rate as fast-growing red algae with the highest rate of 33.24 mg/L/day under 14 hr illumination period per day. However, continuous illumination of 24 hr per day had lower carbon fixation rate of 26.04 mg/L/day. It is obvious that the growth and carbon fixation of either brown or red filamentous algae are farther below the unialgal activity (1%). |
