The effects of temperature and light intensity on the photosynthesis in reef coral Stylophora pistillata
| Autor: | Tai-Ying Wu, 吳岱穎 |
|---|---|
| Rok vydání: | 2004 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 92 The effects of temperature (20, 25 and 28℃) and light intensity (50, 200, 800 μE m-2s-1) on the O2-based and chlorophyll fluorescence of photosystem II (PSII)-based parameters of photosynthesis as well as tissue parameters (chlorophyll a concentration, protein concentration and zooxanthellae density) in the reef coral Stylophora pistillata under different culture time (10, 30, 60, 90 d) was investigated by using respirometry and Diving PAM After different temperature treatments for ten days, coral tissue parameters were similar. The O2-based parameters of photosynthesis, including maximum gross photosynthetic rates (Pgmax), photosynthetic efficiency (?, sub-saturation irradiance (Ik), and Photosystem II (PSII)-based parameters of photosynthesis, including photosynthetic efficiency (? and maximum PSII quantum efficiency (Fv/Fm), were similar under different temperature treatments. However, the maximum rate of ETR (ETRmax) of corals at 25 and 28℃ was two times higher than that of corals at 20℃. In addition, the sub-saturation irradiance (Ik-ETR) of corals was highest at 28℃, and lowest at 20℃. This suggests that fluorescence-based photosynthetic parameters were more sensitive to temperature difference. After different temperature treatments for ninety days, most tissue parameters of corals changed, except the protein concentration and chlorophyll a and c ratio. The chlorophyll a and zooxanthellae density were lowest at 20℃. The O2-based parameters of photosynthesis, such as Pgmax, ?and Ik, were highest at 25℃. The ETRmax of corals was higher at 25℃ and 28℃ than that at 20℃. These may be resulted from the high temperature facilitating the enzyme activity. Gross photosynthesis (GP) and ETR of corals under irradiances below 400 μE m-2s-1 or GP less than 14 μmol O2 m-2s-1 at the three temperature treatments. This suggests that diving-PAM may provide a quick and non-invasive way to estimate primary productivity of corals at least under moderate irradiances. The effect of different temperature and light intensity on ETR and Fv/Fm of Stylophora pistillata was compared under different culture time (0, 10, 30, 60, 90 d). The Fv/Fm was inhibited under high light intensity. The temperature stress would enhance this inhibition. The values of ETRmax were unchanged under medium and low light intensity treatments, but decreased under high light intensity treatment. In addition, the ETRmax was higher with increasing temperature. The ?ETR was inhibited by high light intensity and high temperature. The effect of light intensity on Ik-ETR was different under different temperature treatments. The effects of medium and high light were more obvious with increasing temperature. These results suggest that when corals were under different temperatures and light intensities, they may acclimate in different ways. Coral photosynthesis, however, would more likely be inhibited by high light intensity. Furthermore, when they were stressed by temperature and light intensity synergistically, the impacts on coral photosynthesis would be more serious. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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