一种基于微电极的珊瑚共生体光补偿点测定方法探讨

An exploration on the method of measuring light compensation point of coral holobiont with microelectrode

珊瑚虫与虫黄藻互利共生形成共生体,虫黄藻通过光合作用为珊瑚虫提供重要的能量来源。珊瑚共生体的光补偿点可以较好地指示珊瑚的光适应性,是重要光合特性指标,但其测定方法鲜有报道。利用溶氧微电极结合光强可调节光源,以鹿角杯形珊瑚为实验材料,依据扩散平衡理论,建立了一种造礁石珊瑚的光补偿点的测定方法。实验结果表明珊瑚的扩散边界层溶氧浓度会快速响应光强变化。珊瑚扩散边界层溶氧浓度与光合有效辐射具有较好的相关性,且光强由高降低过程测得的相关系数更高。实验测得鹿角杯形珊瑚的光补偿点较低,为1.52μE/m 2/s,与喜阴植物的光补偿点相当。相对较低的光补偿点利于珊瑚栖居于水深范围更广的区域,有助于扩展珊瑚的生态位。溶氧微电极相关技术和方法在珊瑚光合作用研究中具有广泛的应用前景。

The coral holobiont is a complex system containing the coral polyp and its symbiotic zooxanthellae.Zooxanthellae provides an important source of energy for coral polyps through photosynthesis.The light compensation point of coral holobiont can indicate the light adaptability of coral,and it is an important photosynthetic characteristic index.However,the measurement of light compensation points of the coral holobiont was little reported.Here we reported a method for determining the light compensation point of coral holobiont.According to the theory of diffusion equilibrium,the light compensation point of coral Pocillopora damicornis was determined by using dissolved oxygen microelectrode combined with light intensity adjustable light source.Our results showed that the concentration of dissolved oxygen in coral diffusion boundary layer responded rapidly to the change of photosynthetically active radiation(PAR).The concentration of dissolved oxygen in coral diffusion boundary layer was highly correlated with the PAR,and higher correlation coefficient was achieved in the process of PAR decreasing.The light compensation point of the coral P.damicornis was 1.52μE/m 2/s,which was equivalent to those of shade-tolerant plants.A relatively low light compensation point allowed coral P.damicornis to inhabit a wider range of water depths,which expanded the habitat of coral.The dissolved oxygen microelectrode related techniques and methods had a wide application prospect in the research of coral holobiont photosynthesis.