經由測量葉綠素螢光所計算出來的光合作用之最大量子效率（Fv/Fm）可以用來偵測單細胞藻類是否受到營養鹽限制。因為藍綠細菌與一般真核藻類色素成分不同，所以在應用至海洋研究之前必須先找出最佳的測量設定。首先在設定單次更新的飽和閃光（STF）方面，發現實驗室培養的聚球藻 Synechococcus spp. CH0129 必須使用長度為 150 μs 的 STF 激發光源，才能夠測得準確的 Fv/Fm 值，但在測量海洋樣本時，則將 STF 時間設為 80 μs 就能得到準確的測值。而在儀器偵測極限方面，使用 Synechococcus spp. CH0129 做連續稀釋後分別進行測量，發現實驗室內所培養的聚球藻細胞數至少要維持在 105 cells ml-1 以上，且螢光值平均相對誤差必須控制在 9% 以下，才可以正確的量得聚球藻樣本之 Fv/Fm 數值。但海洋中聚球藻濃度常有降至 105 cells ml-1 以下的機會，因此必須使用濃縮細胞的方式來提高測量的準確性，結果顯示濃縮步驟可以大幅降低平均相對誤差值，但濃縮後測得的 Fv/Fm 值和濃縮前沒有顯著差異，海上實驗的結果亦與實驗室結果相符。另外亦將三株不同的聚球藻培養在缺磷的培養基中，觀察磷酸鹽多寡對 Fv/Fm 的影響，在健康良好的狀態下三者 Fv/Fm皆在0.19 ~ 0.32間，而當磷酸鹽缺乏時，在兩株以藻紅素為主要色素的聚球藻 Synechococcus spp. CH0129 及 Synechococcus sp. WH7803 中，Fv/Fm 會開始下降，同時細胞生長會減緩並且提早進入停滯期，且 APA 活性亦會上升，但另一株以藻藍素為主要色素的 Synechococcus sp. WH5701 則在全營養鹽組和缺磷組之間 Fv/Fm 值沒有差異。根據實驗室結果，設定 Fv/Fm 0.25 ~ 0.35為聚球藻是否缺乏營養鹽的判斷標準。將以上結果應用於 2008 年 4 月 7 日黑潮測站，由 2 m、10 m、25 m、50 m 樣本直接測得的 Fv/Fm 分別為 0.28、0.25、0.30、0.32，平均相對誤差值皆介於 2.25% ~ 5.91% 之間，根據上述標準，四個深度的超微浮游植物皆處於健康良好的狀態。

The influence of nutrient stress on phytoplankton growth can be estimated using the maximum quantum efficiency of photosynthesis, or Fv/Fm. Since the composition of photosynthetic pigments in cyanobacteria is different from that in eukaryotic phytoplankton, suitable settings must be determined before conducting this measurement in the ocean. In laboratory, cultures the duration of single turnover flash, STF, had to be extended to 150 μs to correctly measure Fv/Fm in Synechococcus spp. CH0129, but in oceanic samples, an STF of 80 μs long was enough to obtain an accurate Fv/Fm. To determine the detection limit of Flurorescence Induction and Relaxation (FIRe) system, cells of Synechococcus spp. CH0129 were diluted to various concentrations prior to measurement. The result indicated that the cell concentration must be maintained above 105 cells ml-1 and a relative error maintained below 9% were necessary to obtain correct Fv/Fm values. Since abundances of Synechococcus in the ocean are usually less than 105 cells ml-1, the effect of concentrating cells was evaluated. The result indicated that concentrating cells significantly reduced the relative error and improved accuracy. Results of concentrating field samples agreed with those observed in laboratory. In addition, 3 species of unicellular Synechococcus were incubated in media containing different concentrations of phosphate. The effects of phosphate starvation on Fv/Fm were evaluated in the 3 Synechococcus strains, and Fv/Fm of healthy cultures all fell in the range between 0.19 and 0.32. In the cultures of phycoerythrin-containing Synechococcus strain CH0129 and strain WH7803, Fv/Fm decreased while alkaline phosphatase activity, APA, increased when cells entered stationary phase. However, in the phycocyanin-containing strain WH5701, decreasing Fv/Fm did not vary between the treatments of complete nutrients and of phosphate starvation. Based on experimental results observed in laboratory, 0.25 ~ 0.35 was proposed as the criterion for Synechococcus Fv/Fm in healthy conditions. In ocean applications, ultra-phytoplankton were collected from 2, 10, 25, and 50 m at a station near Kuroshio on April 7, 2007. All values of Fv/Fm ranged from 0.25 ~ 0.32, and relative errors were constantly below 9%. Using the predetermined criterion, ultra-phytoplankton at the study site were likely in a healthy state.

謝辭……………………………………………………………………i
摘要……………………………………………………………………ii
英文摘要………………………………………………………………iv
目錄……………………………………………………………………vi
表目錄…………………………………………………………………vii
圖目錄…………………………………………………………………viii
前言……………………………………………………………………1
材料與方法……………………………………………………………6
結果……………………………………………………………………14
討論……………………………………………………………………20
參考文獻………………………………………………………………26
附表……………………………………………………………………30
附圖……………………………………………………………………35

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