光质对三角褐指藻光保护过程的影响

Effect of light quality on the photoprotection process of Phaeodactylum tricornutum

光能一方面驱动光合作用固定二氧化碳,另一方面当光能过剩就会对光合细胞产生氧化性损伤,甚至导致细胞死亡。硅藻等光合生物通过叶绿素荧光非光化学淬灭(NPQ)把过剩的光能转化为无害的热,达到保护细胞的目的。硅藻 NPQ 的诱导受硅甲藻黄素循环调节,并且与众多环境因子密切相关。作者通过对海洋环境的模拟,研究了不同光质下三角褐指藻(Phaeodactylum tricornutum)受到的影响测定并比较了红、绿、蓝 3 种单色光处理的三角褐指藻响应高光胁迫时的 NPQ 及硅甲藻黄素循环的差异。叶绿素荧光的结果显示,在相同的胁迫性强光和胁迫时间内,蓝光下处理的三角褐指藻形成的 NPQ 更高,而且胁迫阶段淬灭的荧光在低光阶段恢复的更快。色素测定的结果显示, 3 种单色光下处理的三角褐指藻的硅甲藻黄素循环的环脱氧比(DEPS)与对照组没有显著差异。实验结果表明,蓝光对三角褐指藻响应高光、形成 NPQ 至关重要。

Light is essential to drive photosynthetic carbon assimilation. However, light may also cause serious oxidative damage if photosynthetic organisms captured excessive light energy without being dissipated. Diatoms and other photosynthetic organisms dissipate excessive light energy into harmless heat by non-photochemical quenching (NPQ) of chlorophyl fluorescence. NPQ in diatoms is regulated by the diadinoxanthin cycle and influ- enced by various environmental conditions. This study investigated the effects of different light qualities on the photoprotection process of Phaeodactylum tricornutum by simulating the marine environment. Cells of P. tricornu- tum were treated under monochromatic light conditions (i.e., red, green, and blue lights) for days and stressed under high light. Then, the kinetics of NPQ were measured. The data indicate that NPQ of the blue light group was sig- nificantly higher than that of the other groups. Moreover, NPQ of chlorophyl fluorescence relaxed more rapidly during the subsequent low-light period. Meanwhile, the data show that there was no significant difference in the diadinoxanthin cycle among these groups. In conclusion, the data confirm that, compared with red and green lights, blue light is more beneficial and maintains the high potential of NPQ in P. tricornutum.