Effects of solar UV radiation on photosynthetic performance of the diatom Skeletonema costatum grown under nitrate limited condition

doi:2014.29.1.27

Algae > Volume 29(1); 2014 > Article

Algae 2014;29(1): 27-34. doi: https://doi.org/10.4490/algae.2014.29.1.027

Gang Li¹^,2 and Kunshan Gao¹^,*

¹State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian 361005, China
²Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, CAS, Guangzhou, Guangdong 510301, China

*Corresponding Author

Email: ksgao@xmu.edu.cn

ABSTRACT

Availability of nutrients is known to influence marine primary production; and it is of general interest to see how nutrient limitation mediates phytoplankton responses to solar ultraviolet radiation (UVR, 280-400 nm). The red tide diatom Skeletonema costatum was cultured under nitrate (N)-limited and N-replete conditions and exposed to different solar irradiation treatments with or without UV-A (315-400 nm) and UV-B (280-315 nm) radiation. Its photochemical quantum yield decreased by 13.6% in N-limited cells as compared to that in N-replete ones under photosynthetically active radiation (PAR)-alone treatment, and the presence of UV-A or UV-B decreased the yield further by 2.8 and 3.1%, respectively. The non-photochemical quenching (NPQ), when the cells were exposed to stressful light condition, was higher in N-limited than in N-replete grown cells by 180% under PAR alone, by 204% under PAR + UV-A and by 76% under PAR + UV-A + UV-B treatments. Our results indicate that the N limitation exacerbates the UVR effects on the S. costatum photosynthetic performance and stimulate its NPQ.

Key words: diatom; N limitation; N repletion; photosynthesis; Skeletonema costatum; UVR