Photosynthetic response of floating Ulva prolifera to diurnal changes of in-situ environments on the sea surface
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During yellow sea green tide outbreak, the thalli of Ulva prolifera drifted more than 350 km on the sea surface from offshore of Jiangsu Province to Qingdao city, where they were exposed to complex changes of local environments. The purpose of this study is to investigate the response of the thalli to diurnal changes of environments on the sea surface, and a sea surface environment simulator (SSES) was designed to simulate the natural environment of floating U. prolifera mat. A control experiment is designed in the laboratory, which was processed under suitable conditions (20°C for temperature, 72 μmol photons/(m 2 ·s) for light intensity and 30 for salinity), and an in-situ research was conducted to study the photosynthetic responses of floating U. prolifera to diurnal changes of environments. The results show that the photosynthetic efficiency of the thalli decreased gradually with time, and decreased rapidly after 14:00 local time (LT). After exposed to the environment on the sea surface for 6 h, the photosynthetic activity of the thalli decreased significantly. Furthermore, physiological-level and molecular-level experiments revealed that non-photochemical quenching (NPQ), cyclic electron flow (CEF) and energy redistribution between PSI and PSII all played an important role in the strong photosynthetic plasticity of U. prolifera. NPQ is the most important photoprotective responses to environmental changes before 12:00 LT. The results also confirmed that the CEF and energy redistribution between PSI and PSII are the main synergistic effects for the thalli to adapt to the environmental changes when the process NPQ cannot work. And the result can further reveal the reason why U. prolifera can adapt to the living condition of long distance drift on the sea surface. The findings of this research could provide a theoretical basis for explaining outbreaks of the green tide and instructing the management of the problem.
Keywordphotosynthetic system floating Ulva prolifera diurnal change photosynthetic plasticity
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- Huang W, Fu P L, Jiang Y J, Zhang J L, Zhang S B, Hu H, Cao K F. 2013. Differences in the responses of photosystem I and photosystem II of three tree species Cleistanthus sumatranus, Celtis philippensis and Pistacia weinmannifolia exposed to a prolonged drought in a tropical limestone forest. Tree Physiology, 33 (2): 211–220.CrossRefGoogle Scholar
- Joët T, Cournac L, Peltier G, Havaux M. 2002. Cyclic electron flow around photosystem I in C 3 plants. In vivo control by the redox state of chloroplasts and involvement of the NADH–dehydrogenase complex. Plant Physiology, 128 (2): 760–769.Google Scholar
- Liu D Y, Keesing J K, Dong Z J, Zhen Y, Di B P, Shi Y J, Fearns P, Shi P. 2010. Recurrence of the world’s largest green–tide in 2009 in Yellow Sea, China: porphyra yezoensis aquaculture rafts confirmed as nursery for macroalgal blooms. Marine Pollution Bulletin, 60 (9): 1 423–1 432.CrossRefGoogle Scholar
- Liu F, Pang S J, Chopin T, Gao S Q, Shan T F, Zhao X B, Li J. 2013. Understanding the recurrent large–scale green tide in the Yellow Sea: temporal and spatial correlations between multiple geographical, aquacultural and biological factors. Marine Environmental Research, 83: 38–47.CrossRefGoogle Scholar
- Owens T G. 1986. Light–harvesting function in the diatom Phaeodactylum tricornutum II. Distribution of excitation energy between the photosystems. Plant Physiology, 80 (3): 739–746.Google Scholar
- Plouguerné E, Le Lann K, Connan S, Jechoux G, Deslandes E, Stiger–Pouvreau V. 2006. Spatial and seasonal variation in density, reproductive status, length and phenolic content of the invasive brown macroalga Sargassum muticum (Yendo) Fensholt along the coast of Western Brittany (France). Aquatic Botany, 85 (4): 337–344.CrossRefGoogle Scholar
- Ye N H, Zhuang Z M, Jin X S, Wang Q Y, Zhang X W, Li D M, Wang H X, Mao Y Z, Jiang Z J, Li B, Xue Z X. 2008. China is on the track tackling Enteromorpha spp. forming green tide. In: Nature Precedings. Nature Publishing Group. 2008.Google Scholar