Photosynthetic characteristics of two new chlorophyll b-less rice mutants

Two yellow rice mutants VG28-1 and VG30-5 were obtained during the tissue culture process from a rice plant (cv. Zhonghua No. 11, japonica) with inserted maize Ds transposon element. Absorption spectra and pigment composition showed that two mutants had no chlorophyll (Chl) b and lower Chl a content in comparison to the wild type (WT). Net photosynthetic rate (P-N), total electron transport rate (J(F)) photochemical quenching (q(p)), quantum yield of PS2 dependent non-cyclic electron transport (PhiPS2) fraction of P-rate, and leaf area were lower but F-v/F-m and apparent quantum yield (AQY) remained at similar levels as in the WT plant. Xanthophyll cycle pool size (V+A+Z) on a Chl basis, and de-epoxidation state were enhanced in the mutants. The mutants had larger amounts of soluble protein and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCO), especially the small subunit of RuBPCO, than WT. The characteristics of two rice mutants differed somewhat from the other common Chl b-less mutants originating from mutagenic agent treatments.