微微藻形態與生理之研究

Abstract

微微藻（picoplankton）泛指細胞直徑介於0.2～5μm之間的浮游生物，廣泛分佈於各種水體中，其生活方式有異營與自營兩類，其中，自營性的藍綠菌在海洋中是主要的生產者。關於微微藻的研究範圍極廣，營養價值、生理特性、生態地位及分類皆為目前熱門的研究方向，但大多的文獻資料都是以已知種類的微微藻為研究對象。 本研究自採集之水樣中，以微生物純化的方法分離出之純種微微藻為研究對象，分別就其形態、分類與生理三個部分做探討：（一）在光學顯微鏡下觀察，並拍攝掃瞄式電子顯微鏡（SEM）相片對其形態做初步的研究。（二）分別抽取其DNA後以16s rDNA來定序並以此分類。（三）抽取其色素並測定含量；研究各個藻株在不同光強度下的生長速率與光合色素含量變化。 本論文的結論如下：（一）在定序部分，所夾取之16s rDNA序列長度最好在1500bp左右，才能有效的鑑定種類。（二）本研究在翡翠水庫不同深度所採集的微微藻，他們的外型大小、光合色素比例、對不同光照強度的反應，皆與原本生活的水深有關。Planktonic organisms can be subdivided based on dimensional criteria, and picoplankton are defined on 0.2-5 μm size-scale organisms. Picoplankton are distributed worldwide and are ubiquitous in all types of waters, including autotrophic picoplankton and heterotrophic picoplankton. Autotrophic picoplankton are major players in carbon production in all aquatic ecosystems. Recently picoplankton are popular subjects in research, and most of them are interested in nutritive values, physiological characterizations, ecological roles, and categorization. In those studies, most are aimed at known picoplankton, but there are lots of unknown species in biosphere. In this study, picoplankton were isolated in water samples, and furthermore be categorized by morphology and physiological characterizations. There are three parts in this study: (I) Morphological observations in microscopy and scanner electric microscopy. (II) Categorization by blasting of 16S sequence. (III) Physiological characterizations by determining growth rates and the level of photosynthetic pigments of isolated picoplankton in different light conditions. According to the data of this study, picoplankton from different depth of the water in Fei Cui reservoir are also different in morphology and physiological characterizations, suppose the pressure of the depth of the water affect. In addition, the conclusion also advice that the best length of 16S sequence is more than 1500 bp for more effective blasting.