{"id":{"repo_id":"brock","oai_identifier":"oai:brocku.scholaris.ca:10464/5127"},"canonical_url":"https://search.dev.ndltd.org/etd/brock/oai:brocku.scholaris.ca:10464/5127","repository":{"repo_id":"brock","name":"Brock University","base_url":"https://brocku.scholaris.ca/server/oai/request"},"display":{"title":"Fluorescence Studies of Photosystem II Fluorescence Quenching During Desiccation","abstract":"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.","abstract_html":"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.","abstract_has_math":false,"creators":["Schaven, Kristin S."],"institution":"Brock University","degree_name":"M.Sc. Biological Sciences","degree_level":"Masters","degree_discipline":"Faculty of Mathematics and Science","degree_department":"Department of Biological Sciences","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013-12-15","date_published":"2013-12-15","updated_at":"2026-07-24T01:22:56Z","subjects":["Chlorophyll Fluorescence, Photosystem II, Nonphotochemical Quenching, Desiccation Tolerance"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10464/5127","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Department of Biological Sciences"]},{"key":"dc:creator","label":"Author","values":["Schaven, Kristin S."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2013-12-15T15:29:43Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-04-15T09:00:06Z"]},{"key":"dc:date.issued","label":"Date","values":["2013-12-15"]},{"key":"dc:type","label":"Dc Type","values":["Electronic Thesis or Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Faculty of Mathematics and Science"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.Sc. Biological Sciences"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Brock University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chlorophyll Fluorescence, Photosystem II, Nonphotochemical Quenching, Desiccation Tolerance"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10464/5127"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["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."]},{"key":"dc:title","label":"Title","values":["Fluorescence Studies of Photosystem II Fluorescence Quenching During Desiccation"]}]}],"canonical_facts":{"dc:contributor.department":["Department of Biological Sciences"],"dc:creator":["Schaven, Kristin S."],"dc:date.accessioned":["2013-12-15T15:29:43Z"],"dc:date.available":["2014-04-15T09:00:06Z"],"dc:date.issued":["2013-12-15"],"dc:description.abstract":["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."],"dc:identifier.uri":["http://hdl.handle.net/10464/5127"],"dc:language.iso":["eng"],"dc:subject":["Chlorophyll Fluorescence, Photosystem II, Nonphotochemical Quenching, Desiccation Tolerance"],"dc:title":["Fluorescence Studies of Photosystem II Fluorescence Quenching During Desiccation"],"dc:type":["Electronic Thesis or Dissertation"],"thesis:degree_discipline":["Faculty of Mathematics and Science"],"thesis:degree_level":["Masters"],"thesis:degree_name":["M.Sc. Biological Sciences"],"thesis:institution_name":["Brock University"]},"updated_at":"2026-07-24T01:22:56Z"}