铜绿微囊藻光合活性对LED光短期暴露的响应

RESPONSES OF PHOTOSYNTHETIC ACTIVITY OF MICROCYSTIS AERUGINOSA ON SHORT-TERM EXPOSURE TO DIFFERENT LED LIGHTS

  • 摘要: 为探究LED光对蓝藻光合活性的影响, 以铜绿微囊藻Microcystis aeruginosa PCC 7806为对象, 25 μmol photons/(m2·s)白色荧光灯为对照, 检测了不同光质光强LED处理2h 的光合活性。结果表明, 与对照相比, 25—50 μmol photons/(m2·s) LED红光和蓝光、25—100 μmol photons/(m2·s) LED白光和绿光处理下, 细胞光合活性(Fv/Fm)显著提高。大于100 μmol photons/(m2·s)的LED红光和蓝光、大于200 μmol photons/(m2·s)的LED白光及大于500 μmol photons/(m2·s)的LED绿光处理对光合活性有显著抑制作用, 光系统Ⅱ(PSⅡ)最大光化学效率Fv/Fm、电子传递速率ETR(Ⅱ)、光量子产量Y(Ⅱ)、光系统Ⅰ(PSⅠ)电子传递速率ETR(Ⅰ)、光量子产量Y(Ⅰ)随光强升高而降低; \textQ_\textA^- 和QB间电子传递阻遏程度、PSⅡ无活性反应中心(PSⅡx)的比例及单个活性反应中心吸收的能量通量(ABS/RC)、单个活性反应中心耗散的总能量(DI0/RC)、细胞单位面积藻体吸收的能量(ABS/CS0)、单位面积藻体热耗散的能量(DI0/CS0)随光强升高而增加; 而单个活性反应中心传递的电子通量(ET0/RC)、单位面积藻体活性反应中心捕获的能量通量(TR0/CS0)、单位面积藻体电子传递的能量通量(ET0/CS0)随光强升高而降低(P<0.05); 单个活性反应中心捕获的激发能量通量 (TR0/RC)无显著变化(P>0.05); 在同一光强不同光质作用下, Fv/FmETR(Ⅱ)、Y(Ⅱ)、ETR(Ⅰ)、Y(Ⅰ)的下降程度、\textQ_\textA^-和QB间电子传递阻遏程度、PSⅡx、ABS/RCDI0/RC、ABS/CS0DI0/CS0的增加程度、ET0/RCTR0/CS0ET0/CS0的降低程度均表现为红光最大, 绿光最小。这些结果显示, 四种LED光质在低光强下可显著提高微囊藻光合活性并保证能量分配的平衡; 高光强通过影响PSⅡ 反应中心、抑制PSⅡ电子传递链受体侧的电子传递来降低微囊藻光合活性, 同时, 细胞大量吸收的光能通过增加热耗散、降低电子传递量子产额的方式来保护和缓解强光胁迫压力。研究揭示了铜绿微囊藻光合活性对LED光的响应机制, 确认高光强LED光可抑制藻细胞光合活性, 是防控微囊藻暴发性增殖的可能技术途径。

     

    Abstract: To investigate the effect of LED light on the photosynthetic activity of cyanobacteria, the photosynthetic activity of Microcystis aeruginosa PCC 7806 was examined after 2h of LED treatment with different light quality and intensity using 25 μmol photons/(m2·s) of white fluorescent light as control. When compared to the control, results indicated that the cell photosynthetic activity (Fv/Fm) soared significantly under 25—50 μmol photons/(m2·s) LED red and blue light, and 25—100 μmol photons/(m2·s) LED white and green light treatments. LED red and blue light significantly inhibited cell photosynthetic activity at 100 μmol photons/(m2·s), whereas this intensity was more than 200 μmol photons/(m2·s) for the LED white light and 500 μmol photons/(m2·s) for the LED green light, and the maximum photochemical efficiency of photosystem Ⅱ (PSⅡ) Fv/Fm, the electron transfer rate ETR (Ⅱ) and light quantum yield Y (Ⅱ); the photosystem Ⅰ (PSⅠ) electron transfer rate ETR(Ⅰ), and the light quantum yield Y(Ⅰ) decreased with increasing light intensity; with increasing light intensity, the degree of electron transfer blockage between \textQ_\textA^- and QB, the proportion of PSⅡ inactive reaction centers (PSⅡx) and the energy flux absorbed by a single active reaction center (ABS/RC), the total energy dissipated by a single active reaction center (DI0/RC), the energy absorbed by the cell per unit area of algae (ABS/CS0), and the energy dissipated by heat per unit area of algae (DI0/CS0) were increased. Although the flux of electrons transferred by a single active reaction center (ET0/RC), the flux of energy captured per unit area of algal active reaction center (TR0/CS0), and the flux of energy transferred per unit area of algal electrons (ET0/CS0) were all decreased under the action of increasing light intensity (P<0.05), the flux of excitation energy captured by a single active reaction center (TR0/RC) was not changed significantly (P>0.05). Under the action of different light qualities of the identical light intensity, the decline degree of Fv/Fm, ETR (Ⅱ), Y (Ⅱ), ETR (Ⅰ), Y (Ⅰ), the degree of electron transfer blockage between \textQ_\textA^- and QB, the increased degree of PSⅡx, ABS/RC, DI0/RC, ABS/CS0, DI0/CS0, and the decline degree of ET0/RC, TR0/CS0, ET0/CS0 manifested most when subjected to red light therapy and least when subjected to green light treatment. These study results demonstrated that at low light intensities, the four LED light qualities significantly increased the photosynthetic activity of Microcystis aeruginosa and ensured the balance of energy distribution; high light intensities decreased the photosynthetic activity of Microcystis aeruginosa by affecting the PSⅡ reaction center and inhibiting electron transfer on the receptor side of the PSⅡ electron transfer chain, while the large amount of light energy absorbed by the cells protects and alleviates the stress of intense light stress by increasing heat dissipation and reducing the quantum yield of electron transfer. The mechanism of photosynthetic activity of Microcystis aeruginosa in response to LED light was revealed in this study, and it was confirmed that high light intensity LED light can suppress photosynthetic activity of algal cells, which is a feasible technical way to prevent and control the explosive proliferation of Microcystis aeruginosa.

     

/

返回文章
返回