Growth of the terrestrial cyanobacterium Nostoc flagelliforme in response to stresses in aquatic condition

• Main Authors: Wei-Yu Chen, 陳威宇
• Other Authors: Kwee-Siong Tew
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/60836900058793468321

碩士 === 國立東華大學 === 海洋生物多樣性及演化研究所 === 97 === Terrestrial Nostoc flagelliforme is an edible blue-green alga with high economical value in Chinese community. Its growth rate is very low, but can be high when cultured in aquatic condition. However, no sheath is formed when grow under aquatic environment. In this study, we grew N. flagelliforme in liquid medium under different stresses, i.e. under UV radiation, gradual dehydration and re-hydration, and saline water, to mimic some of the stresses that terrestrial N. flagelliforme encountered in nature. When grown under UV radiation, photosynthetic system II (PSII) was significantly higher, whereas the chlorophyll a concentration was lower than in the control. Some vegetative cells were shrunk and the cell sizes were smaller than those in the control. When UV radiation was applied coupling with gradual dehydration, PSII was significantly higher, whereas the chlorophyll a concentration was lower than in the control. After re-hydration, PSII was significantly higher in the UV settings, and so did the chlorophyll a concentration. Morphology of the alga was similar, but was pale in UV settings. When simultaneously exposed the alga to UV and 20 mM of NaCl, the PSII activity was not significantly different, but the chlorophyll a concentration was significantly lower from those exposed to 20 mM of NaCl only. Aggregation and intertwining of long filaments were observed in the NaCl-only set-up.