Fluorescence Studies of Photosystem II Fluorescence Quenching During Desiccation

Poikilohydric organisms have developed mechanisms to protect their photosynthetic machinery during times of desiccation. In hydrated conditions nonphotochemical quenching (NPQ) mechanisms are able to safely dissipate excess excitation energy as heat, but mechanisms of NPQ associated with desiccation tolerance are still largely unclear. In the lichen Parmelia sulcata, photosystem protection has been associated with an energy quenching energetically coupled to PSII and characterized by a fast-fluorescence decay lifetime, and long-wavelength emission. The present study compares the relative ability of green algae and lichens to recover photosynthetic activity after periods of desiccation using steady state fluorescence emission spectroscopy, and picosecond time-resolved fluorescence decay measurements. It was determined that desiccation induced quenching involves an antenna quenching mechanism with similar characteristics appearing in both P. sulcata and green algae. Algae isolated from lichens suggest symbiosis in the lichen appears to enhance this naturally occurring phenomenon and provide greater protection during desiccation.

Name thesis:degree_name

M.Sc. Biological Sciences

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Faculty of Mathematics and Science

Department dc:contributor.department

Department of Biological Sciences

Grantor

Brock University

Year dc:date.issued

2013

Author dc:creator

• Schaven, Kristin S.

• Chlorophyll Fluorescence, Photosystem II, Nonphotochemical Quenching, Desiccation Tolerance

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/10464/5127

OAI identifier oai:identifier

oai:brocku.scholaris.ca:10464/5127