为揭示岛礁潮间带大型海藻对升温的光合响应, 以及它们在不同光质下的光合效率, 并为岛礁海藻场建设与藻种培育提供理论依据, 利用叶绿素荧光和光合放氧技术, 研究了绿华岛潮间带4种大型海藻(孔石莼、舌状蜈蚣藻、鼠尾藻和羊栖菜)对升温(温度分别为15、20、25℃)和不同光质(白、红、绿、蓝光)的光合响应。结果显示: 升温降低这些海藻光系统Ⅱ (PSⅡ)的最大量子产量(Fv/Fm), 但显著提升它们在强光下(900μmol photons m-2·s-1)的有效量子产量(Y(Ⅱ))、光合修复与损伤速率的比值(r/k)及光化学淬灭(qP); 升温显著增大羊栖菜的非光化学淬灭(NPQ), 但显著降低舌状蜈蚣藻的NPQ。与其它海藻相比, 鼠尾藻具有最高的最大相对电子传递速率(rETRmax)、半饱和光强(Ek)、qP和 r/k。在不同光质条件下下, 这些海藻在白、红、绿光下的最大放氧速率(Pmax)无显著差异, 但在蓝光下显著降低, 其中孔石莼的降幅最大。研究表明, 不同海藻对升温和光质的光合响应存在较大差异, 短暂升温有助于4种潮间带大型海藻抵御退潮后的强光, 并提高其在强光下的光合活性, 其中鼠尾藻比其它三种海藻展现出更高的光合活性、耐光性和更好的温度适应性。此外, 在红光和绿光下较强的光合效率反映了这些海藻对潮间带浅水环境的良好适应性。

In order to reveal the photosynthetic response of intertidal macroalgae to temperature rise and their photosynthetic efficiency under different light qualities, and to provide a theoretical basis for the construction of island seaweed farms and the cultivation of seaweed. We usd chlorophyll fluorescence and dissolved oxygen sensors to examine the photosynthetic responses of four macroalgae (Ulva pertusa, Grateloupia livida, Sargassum thunbergii and Sargassum fusiforme) from the intertidal zone of Lvhua Island to temperature (15, 20, 25℃, respectively) and light quality (white, red, green and blue). The results showed that temperature rise reduced the maximum quantum yield (Fv/Fm) of Photosystem II (PSII) in these seaweeds, but significantly enhanced the actual quantum yield (Y(Ⅱ)), ratio of photosynthetic repair to damage rate (r/k) and photochemical quenching (qP) under strong light (900μmol photons m-2·s-1). Temperature rise significantly increased the non-photochemical quenching (NPQ) of S. fusiforme, but the contrary was observed in G. livida. Compared to other seaweeds, S. thunbergii exhibits the highest maximum relative electron transfer rate (rETRmax), half-saturated light intensity (Ek), qP and r/k. Under different light qualities, these seaweeds show no significant differences in maximum photosynthetic rate (Pmax) under white, red and green light, but Pmax was significantly reduced under blue light, with the greatest decrease observed in U. pertusa. As a result, the photosynthetic responses of different species to temperature rise and light quality varied considerably, the short-term warming helps the four intertidal macroalgae to resist strong light and improve their photosynthetic activity under strong light at low tide. And S. thunbergii was more adapted to strong light and temperature rise than the others. Additionally, the higher photosynthetic efficiency under red and green light reflects their adaptation to the shallow water in the intertidal zone.