The effects of irradiance, temperature, and desiccation on the photosynthesis of a brown alga, Sargassum muticum (Fucales), from a native distributional range in Japan
The effects of irradiance, temperature, and desiccation on the photosynthesis of a brown alga, Sargassum muticum (Fucales), from a native distributional range in Japan
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DOI：
10.1007/s10811-021-02425-z
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发表时间：
2021-03
影响因子：
3.3
通讯作者：
Tomohiro Ito;I. A. Borlongan;Gregory N. Nishihara;H. Endo;Ryuta Terada
中科院分区：
文献类型：
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作者：
Tomohiro Ito;I. A. Borlongan;Gregory N. Nishihara;H. Endo;Ryuta Terada
通过脉冲幅度调制(PAM)-叶绿素荧光仪和光学溶解氧传感器，我们确定了辐照度、温度和干燥对日本原生分布范围内褐藻马尾藻光合作用的影响。3种温度（8℃、20℃和28℃）下的光合作用-辐照度曲线显示，28℃时最大净光合速率（NPmax）和饱和辐照度最高。在8-36°C（每4个增量）和300 μmol光子m−2s−1条件下测定的总光合速率（GPmax）最大值出现在19.5°C()，这与日本丰度峰值时的海水温度一致。在8 ~ 28℃温度下，光系统II （PSII）的最大量子产率（Fv/Fm）大于0.60，但温度越高，量子产率越低。在3种温度下连续辐照200（低）和1000（高）μmol光子m−2s−1 (12 h)，仅在8°C高辐照下，PSII的有效量子产率（ΔF/Fm’）显著下降；暗驯化12 h后的fv / fm也没有恢复到初始值，说明其对8°C光抑制的敏感性。此外，该藻类在脱水2小时后，80%的水分从菌体流失，在海水中再水化24小时后恢复andΔF/Fm'，这表明该藻类在如此低的水化阈值下具有恢复光合作用的潜力。综上所述，s。相对较高的辐照度、较宽的温度范围（8-28°C）和干燥性解释了其潜在的高侵入能力。
We determined the effects of irradiance, temperature, and desiccation on the photosynthesis of a brown alga,Sargassum muticum(Fucales), from its native distributional range in Japan by using a pulse amplitude modulation (PAM)-chlorophyll fluorometer and optical dissolved oxygen sensors. Photosynthesis–irradiance curves at three temperatures (8, 20, and 28°C) showed that the maximum net photosynthetic rates (NPmax) and saturation irradiance were highest at 28°C. Gross photosynthesis determined at 8–36°C (every four increments) and 300 μmol photons m−2s−1showed that the maximum gross photosynthetic rate (GPmax) occurred at 19.5°C (), which is consistent with the seawater temperature at its peaked abundance in Japan. The maximum quantum yields (Fv/Fm) of photosystem II (PSII) during the 72-h temperature exposures were above 0.60 at 8–28°C but dropped at higher temperatures. Continuous exposure (12 h) to irradiance of 200 (low) and 1000 (high) μmol photons m−2s−1at three temperatures showed remarkable decline in the effective quantum yields (ΔF/Fm') of PSII under high irradiance at 8°C only; theFv/Fmmeasured after 12-h dark acclimation also did not recover to initial values, signifying its sensitivity to photoinhibition at 8°C. Furthermore, the alga exhibited tolerance to 2 h of desiccation with 80% of water loss from the thallus, andΔF/Fm'recovered after 24 h of rehydration in seawater, suggesting potential of photosynthetic recovery of this alga at such low hydration threshold. In conclusion, the adaptation ofS. muticumto relatively high irradiance, to broad range of temperature (8–28°C), and to desiccation explains its potentially high invasive capacity.