High photosynthetic efficiency of a rice (Oryza sativa L.) xantha mutant

Comparative analysis revealed that a xantha rice mutant (cv. Huangyu B) had higher ratios of chlorophyll (Chl) alb and carotenoids/Chl, and higher photosynthetic efficiency than its wild type parent (cv. II32 B). Unexpectedly, the mutant had higher net photosynthetic rate (P-N) than II32 B. This might have resulted from its lower non-photochemical quenching (q(N)) but higher maximal photochemical efficiency (F-v/F-m), higher excitation energy capture efficiency of photosystem 2 (PS2) reaction centres (F-v'/F-m'), higher photochemical quenching (q(p)), higher effective PS2 quantum yield (phi(PS2)), and higher non-cyclic electron transport rate (ETR). This is the first report of a chlorophyll mutant that has higher photosynthetic efficiency and main Chl fluorescence parameters than its wild type. This mutant could become a unique material both for the basic research on photosynthesis and for the development of high yielding rice cultivars.