Response Of Photosynthetic Process Of Phaeodactylum Tricornutum To Changes In Marine Environment

Diatom is a widely distributed single-cell eukaryotic algae that is an important contributor to marine primary productivity and plays an important role in the global carbon cycle.Diatoms have a strong adaptability to the environment,which is closely related to their flexible photosynthesis regulation mechanism.Phaeodactylum tricornutum is a common diatom with strong adaptability to the environment.It has a short culture period in the laboratory,a clear genetic background,and complete genome sequencing.It is a good material for studying the regulation mechanism of photosynthesis.In this thesis,we have studied the photosynthesis physiological activities and biochemical processes of P.tricornutum with the change of environmental factors,light and inorganic carbon source.(1)The photoprotective process of P.tricornutum in response to changes in light intensity and light quality.The results show that the light quality has a significant effect on non-photochemical quenching(NPQ)under the strong light stress of P.tricornutum.The NPQ formed by the blue-conditioned condition of P.tricornutum under high light stress was significantly higher than that of other light-quality conditions,while the lower NPQ formed by the red-light conditional cultur-e of P.tricornutum responded to high light stress.This result indicates that blue light is essential for the maintenance of the photoprotective response mechanism of P.tricornutum,and blue light receptor may play an important role in mediating the transcription and expression of photoprotective regulators of P.tricornutum.(2)The ocean is an important carbon sink in the world,which is closely related to the operation of phytoplankton-mediated biological carbon pumps.However,with the increasing degree of industrialization in the world,the concentration of carbon dioxide in the atmosphere is also increasing annual,which undoubtedly has a profound impact on the carbonate system in seawater,and will also produce a multifaceted effect of the photosynthetic carbon fixation in diatoms.We used the different carbon dioxide concentrations to cultivate the exponential phase of P.tricornutum,monitored the biomass changes,measured and compared the photosynthetic physiology of P.tricornutum grown under different carbon dioxide concentrations.The results show that the increase of carbon dioxide concentration in the air greatly promotes the growth of P.tricornutum,and the increase of inorganic carbon source also affects the high light stress response of P.tricornutum.Meanwhile,the pH of the culture system has undergone tremendous fluctuations during the cultivation process.The research results of this paper have reference significance for further understanding of the regulation mechanism of diatoms about photosynthesis process response to environmental changes.