Abstract: Yellow leaf cabbage mutant（‘YL-1’）and its near isogenic line‘WT708’were used to compare their difference. Mutant‘YL-1’showed yellow leaf phenotype from cotyledon stage and existed throughout the life cycle. Compared with‘WT708’，‘YL-1’had smaller leaves and less plant height. The head height of‘YL-1’was 39.0% of‘WT708’. The photosynthetic pigment content in‘YL-1’leaves was significantly lower than that in‘WT708’.‘YL-1’had fewer chloroplasts and base grains，less grana lamellae stacked pile and irregular arrangement of base grains. The chlorophyll fluorescence parameters F_o，F_m，F_o′，F_v/F_m，F_v′/F_m，Ф^_PSⅡ，Q_P，Q_N and ETR in‘YL-1’were significantly lower than those in‘WT708’. Lower photosynthetic pigment content leads to the lower light-harvesting capacity and photochemical conversion efficiency of the PSⅡreaction center. As temperature decreased，the difference of photosynthetic pigment content between‘YL-1’and‘WT708’gradually increased.′

Key words: Brassica oleracea L. var. capitata, chlorophyll-reduced mutant, photosynthetic pigment