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Distribution of excitation energy in photosynthesis: a study of heat loss, photo chemical activity and fluorescence emission in intact calls of cyanobacterium.

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dc.contributor.author Salehian, Omid. en_US
dc.date.accessioned 2009-10-02T13:19:57Z
dc.date.available 2009-10-02T13:19:57Z
dc.date.issued 1991-10-02T13:19:57Z
dc.identifier.uri http://hdl.handle.net/10464/2746
dc.description.abstract Photosynthetic state transitions were investigated in the cyanobacterium Synechococcus sp. PCC 6301 by studying fluorescence emission, heat loss, and PS I activity in intact cells brought to state 1 and state 2. 77K fluorescence emission spectra were modelled with a sum of 6 components corresponding to PBS, PS II, and PS I emissions. The modelled data showed a large decrease in PS II fluorescence accompanied with a small increase in the PS I fluorescence upon transition to state 2 for excitation wavelengths absorbed by both PBS and ChI ll.. The fluorescence changes seen with ChI .a. excitations do not support the predictions of the mobile PBS model of state transition in PBS-containing organisms. Measurements of heat loss from intact cells in the two states were similar for both ChI it. and PBS excitations over three orders of magnitude of laser flash intensity. This suggests that the PBS does not become decoupled from PS II in state 2 as proposed by the PBS detachment model of state transition in PBS-containing organisms. PS I activity measurements done on intact cells showed no difference in the two states, in contrast with the predictions of all of the existing models of state transitions. Based on these results a model for state transition In PBScontaining organisms is proposed, with a PS II photoprotectory function. en_US
dc.language.iso eng en_US
dc.publisher Brock University en_US
dc.subject Photosynthesis. en_US
dc.subject Cyanobacteria. en_US
dc.subject Plant luminescence. en_US
dc.subject Bacteria, Luminous. en_US
dc.title Distribution of excitation energy in photosynthesis: a study of heat loss, photo chemical activity and fluorescence emission in intact calls of cyanobacterium. en_US
dc.type Electronic Thesis or Dissertation en_US
dc.degree.name M.Sc. Biological Sciences en_US
dc.degree.level Masters en_US
dc.contributor.department Department of Biological Sciences en_US
dc.degree.discipline Faculty of Mathematics and Science en_US


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