桉树脑和柠檬烯对莱茵衣藻光合特性的影响

为了揭示蓝藻挥发性有机化合物（VOCs）中两种主要萜烯类化合物桉树脑和柠檬烯对其他藻类的化感作用，研究了此两种化合物对莱茵衣藻细胞生长、光合素吸收光谱和光合性能的影响。结果表明，莱茵衣藻在1.6和4 mmol/L桉树脑以及0.4和0.8 mmol/L柠檬烯处理24h后，细胞生长受到明显抑制，与对照相比，细胞密度分别降低了16.7%、50.6%、29.1%和44.4%。同时，1.6和4 mmol/L柠檬烯处理会诱导藻细胞全部死亡。此外，莱茵衣藻光合色素在413、433、457和663 nm处的吸收峰均明显降低，光合色素的各成分发生明显降解，叶黄素甚至在0.8 mmol/L柠檬烯处理下完全降解消失。在桉树脑和柠檬烯处理后，莱茵衣藻从O点到P点的荧光强度均低于对照，并且随处理浓度升高而降低。同时，荧光诱导动力学参数中，φP_o、Ψ_o、φE_o、RC/CS_MS、ABS/CS_M、TR_o/CS_M、ET_o/CS_M和PI_ABS均明显降低，而DI_o/CS_M则明显升高，这表明桉树脑和柠檬烯可抑制莱茵衣藻PSⅡ量子产生和电子传递，并使吸收的光能以热的形式进行耗散。由此可见，桉树脑和柠檬烯可能通过引起其他藻细胞光合色素降解、降低光合性能而发挥化感作用。

EFFECTS OF EUCALYPTOL AND LIMONENE ON THE PHOTOSYNTHETIC ABILITIES INCHLAMYDOMONAS REINHARDTII

This study investigated the allelopathic effects of eucalyptol and limonene, two main terpenoids from cya-nobacteria VOCs, on other algae by focusing on cell growth, absorption spectra of photosynthetic pigments and photo-synthetic abilities usingChlamydomonas reinhardtii. Eucalyptol at 1.6 and 4 mmol/L as well as limonene at 0.4 and 0.8 mmol/L remarkably inhibitedC. reinhardtii cell growth by 16.7%, 50.6%, 29.1% and 44.4%, respectively. Moreover, limonene at 1.6 and 4 mmol/L killed the cells. In addition, an obvious reduction was found in the absorption peaks at 413, 433, 457 and 663 nm. The components of photosynthetic pigments were degraded markedly, and xantho-phyll even disappeared by 0.8 mmol/L limonene treatment. WhenC. reinhardtii cells were treated by eucalyptol and li-monene, the fluorescence intensity from O to P was lower compared to the control, and it was declined with the in-creased compound concentration. In chlorophyll fluorescence transient parameters,φPo,Ψo,φEo,RC/CSM,ABS/CSM, TRo/CSM,ETo/CSMandPIABS were declined remarkably, whileDIo/CSM was raised remarkably, indicating that euca-lyptol and limonene can inhibit the quantum production and electron transport in PSII, and promote the absorbed solar energy to dissipate as heat. Therefore, eucalyptol and limonene might play allelopathic effects in cyanobacteria VOCs via inducing degradation of photosynthetic pigments and reducing photosynthetic abilities in other algae.