Abstract: We investigated the effects of light quality on cell size and physiological activity of algae Microcystis aeruginosa cultured under LED red light, LED green light, LED blue light, and LED white light for 30 culture generations, with white fluorescent light as the control. The results showed that algal cell size cultured under LED blue light and LED green light became significantly larger (P<0.05), and the proportion of cells larger than 3 μm increased by 16.6 and 7.4 times than that under control, respectively. Cell size under LED white light treatment was not significantly different from that of the control (P>0.05), and that under LED red light significantly decreased (P<0.05). The specific growth rate, photosynthetic activity, the content of each cellular component under LED blue light was the highest, followed by LED green light > LED white light > control light > LED red light. Cell size was significantly positively correlated with growth rate, photosynthetic activity, and content of each cell component (P< 0.05). Our results confirmed the effects of light quality on cell size and physiological activities, which was important for the in-depth understanding of the regulatory mechanism of light quality on algae.

Key words: Microcystis aeruginosa, light quality, cell size, physiological activity