Photosynthetic Characteristics And Chlorophyll Fluorescence Of Chlorophyll-deficient Oilseed Rape Mutant (Cr3529)

We investigated the altered features of Chl-protein complexes in the chlorophyll- deficient oilseed rape mutant as compared with wild type by using techniques of pigment analysis, native gel electrophoresis and SDS-PAGE. The analysis of pigments showed that the mutant had significantly less chlorophyll (Chl) b and lower Chl a content comparison to the wild type. The absence of chlorophyll in the mutant resulted in reduction of the major as well as some minor light-harvesting chlorophyll protein complexes (such as CP29) both in the photosystem II and photosystem I. The native gel electrophoresis showed that the PSII/LHCII and PSI/LHCI complexes were somewhat decreased in the mutant. However, the core antenna complexes (CP43 and CP47) of photosystemII in the mutant were not changed or somewhat increased. This suggested that the reduction or loss of the antenna LHCI and LHCII was compensated by an increment in core component. Furthermore, the Chlorophyll fluorescence characteristics of the mutant indicated the changes of the PSII heterogeneity (the decreased of PSIIa and increased of PSIIβ).The photosynthetic characteristics and excitation energy distribution of the mutant was examined using thermoilluminscence and chlorophyll a fluorescence measurements at room temperature and at 77 K. The low temperature (77K) fluorescence emission spectrum showed that the light energy absorption drops in the mutant. The increased of F_PSII/F_PSI in the mutant indicated that more excitation energies to assign to photosystem II. At the same time, the changed of the thylakiod membrane protein phosphorylation in the mutant (Immunoblot analysis with phosphothreonine (Thr (P) antibody) showed that the phosphorylation of light...