Document Detail

Distinct physiological responses to a high light and low CO2 environment revealed by fluorescence quenching in photoautotrophically grown Chlamydomonas reinhardtii.
MedLine Citation:
PMID:  17680341     Owner:  NLM     Status:  MEDLINE    
Mechanisms for countering environmental stress are essential to photosynthetic organisms. Alteration of the photosynthetic apparatus, a mechanism for balancing the flux of light energy and carbon fixation, can be characterized by fluorescence properties. In this study, we have established a simple protocol to determine the extent of energy-dependent quenching (qE) and quenching by state transition (qT) in Chlamydomonas cells by examining their fluorescence properties under light fluctuations. We identified qE as the uncoupler-sensitive NPQ component that was rapidly relaxed upon transition to dark conditions. We characterized the qT component by determining low-temperature fluorescence spectra and analyzing a state-transition-less mutant. By these methods, we observed that similar abiotic stresses-high light conditions (where excess energy is supplied) and low CO2 conditions (where energy utilization is limited)-induced different types of NPQ. High light conditions induced mainly qE-quenching that increased gradually while low CO2 conditions induced mainly qT-quenching that peaked in 20 min and then decreased gradually. That high light and low carbon signals induced different physiological responses suggests that they triggered different genetic responses, which altered protein expression under each of the conditions.
Masakazu Iwai; Nobuyasu Kato; Jun Minagawa
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-08-07
Journal Detail:
Title:  Photosynthesis research     Volume:  94     ISSN:  0166-8595     ISO Abbreviation:  Photosyn. Res.     Publication Date:    2007 Nov-Dec
Date Detail:
Created Date:  2007-12-06     Completed Date:  2008-03-17     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954728     Medline TA:  Photosynth Res     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  307-14     Citation Subset:  IM    
The Institute of Low Temperature Science, Hokkaido University, Sapporo, 060-0819, Japan.
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MeSH Terms
Carbon Dioxide / metabolism,  pharmacology*
Chlamydomonas reinhardtii / drug effects,  metabolism*,  radiation effects
Photosynthesis / drug effects,  physiology,  radiation effects
Reg. No./Substance:
124-38-9/Carbon Dioxide

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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