Effects Of Chlorophyll Deficiency On Photosystem Photochemistry In Rice

A chlorophyll deficient rice mutant Zhenhui 249 was found to possess a high photoinhibiton resistance trait. It maintained maximal photochemical efficiency (Fv/Fm) similar as the its wild type subjected to high light treatment.Modification of PSII photochemistry in chlorophyll deficient rice mutant was investigated. Fluorescence quenching analyses showed that chlorophyll deficiency induced increases the photochemical quenching, but an decrease in the the efficiency of excitation energy capture by open PSII reaction centers, non-photochemical quenching. The analyses of the polyphasic rise of fluorescence transients demonstrated that chlorophyll deficiency decreased the efficiency with which a trapped exciton can move an electron into the electron transport chain further than QA and the quantum yield of electron transport beyond QA, while it decreased the absorption and trapping fluxes per PSII reaction center. Chlorophyll deficiency also resulted in a decrease in the absorption, trapping and electron transport fluxes per leaf cross section as well as a decrease in the concentration of active PSII reaction centers.This study have further in detail how chlorophyll deficiency affects photochemistry activity in both PSII and PSI of the mutant and its wild type during photoinhibition. Our results suggest that after treatment with strong irradiance of three hours, PSII was more suffered from photoinhibition than PSI. Chlorophyll deficient in some degree was not increased susceptibility to high light.