Photosynthesis of Prochloron as affected by environmental factors
Photosynthesis of Prochloron as affected by environmental factors
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DOI：
10.1007/s101260000062
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发表时间：
2001-01-01
影响因子：
3
通讯作者：
Miyachi, S
中科院分区：
文献类型：
--
作者：
Dionisio-Sese, ML;Maruyama, T;Miyachi, S
研究了光强、pH、温度和紫外线照射对从帕劳海鞘寄主髌骨Lissoclinum patella中分离得到的Prochloron光合速率的影响。在500 μ lmol/m(2) / s的饱和光强下，光合作用随光强的增加而增加。pH为8 ~ 9时最大，pH为7时几乎完全抑制。最适温度为35 ~ 40℃，低于或等于20℃和45℃时，光合作用缺失。当共生体在小于或等于20度的条件下孵育1小时后转移到35度时，可恢复，但在45度的条件下则不能恢复。紫外辐照对丙氯龙的光合作用有明显的抑制作用，但对体内无抑制作用。这种保护是由覆盖海鞘菌落的外衣带来的，其中含有吸收紫外线的真菌孢素样氨基酸。这些结果表明，热带海洋环境的特征条件在很大程度上决定了Prochloron的生态分布，海鞘的外衣保护生物体免受紫外线辐射。
The effects of light intensity, pH, temperature, and UV irradiation on the photosynthetic rate of Prochloron isolated from the ascidian host Lissoclinum patella, collected from Palau, were examined. Photosynthesis increased with light intensity with saturation at 500 mu lmol/m(2) per second. It was maximum at pH 8 to 9 but almost completely suppressed below pH 7. The optimum temperature was 35 degrees to 40 degreesC, but the photosynthesis was absent at less than or equal to 20 degreesC and at 45 degreesC. It was recovered when the symbiont was transferred from 1 hour of incubation at less than or equal to 20 degreesC to 35 degreesC but not when transferred from incubation at 45 degreesC. Ultraviolet irradiation severely inhibited the photosynthesis of Prochloron in isolation but not in vivo. This protection was brought about by the tunic covering the ascidian colony, which contains UV-absorbing mycosporine-like amino acids. These results indicate that the characteristic condition of the tropical marine environment largely determines the ecological distribution of Prochloron, and the ascidian tunic protects the organism from UV radiation.