Does amount of light harvesting complexes play a role in the sensitivity of DCMU-treated Arabidopsis thaliana to high light stress?
|Year of publication||2009|
|MU Faculty or unit|
|Description||Several fluorometric techniques, such as chlorophyll(Chl) fluorescence imaging, saturation pulse method, fast Chl fluorescence transients (OJIPs) were used to study photoinhibition and recovery in potted plants of A. thaliana. To address the role of light harvesting complexes(LHCs), wild type (wt-Columbia), npq (defective in zeaxanthin deepoxidase), and lhc (40 % reduction in LHCs) mutants were used. Responses to short-term (2000 microE m-2 s-1 PAR for 30 min) and long-term (300 microE m-2 s-1 PAR for 30 min plus PS II blocker DCMU) treatments were measured. In short-term experiment, photoinhibition of PS II was apparent as a decrease in Chl fluorescence in OJIPs, PS II quantum yield, and Fv/Fm ratio. The parameters, however, showed rapid recovery after 180 min in dark indicating high capacity of photoprotective mechanisms. Timecourses of Chl fluorescence parameters differed between wt, npq and lhc plants. In long-term treatment, the rate of DCMU (applied into substrate) uptake and interaction with light differed between wt and lhc plants. The results indicated that LHC-deficient A. thaliana mutants were more sensitive to photoinhibition than wt control. Supported by GACR52206097.|