LAUSR

The demand for high-yield cultivars of Saccharina japonica in farming areas calls for a practical and simple method to select desired parental plants for seed breeding. In this study, we evaluated PSII photosynthetic performance by measuring chlorophyll fluorescence and the nutrient uptake rate in both the micro-gametophyte and macro-young-sporophyte in five native strains (S1, S2, S3, S4 and S5) of S. japonica with different morphological characteristics. We found significant differences in PSII photosynthetic parameters and nitrate uptake rates between the strains studied in both gametophytes and young sporophytes. Female gametophytes of all strains presented larger cell sizes than males (P  0.747), the PSII photosynthetic parameters of female gametophytes (R2 > 0.689) and the nitrate uptake rate of young sporophytes (R2 = 0.640). These findings are considered promising for the future seed breeding of renewable, high-yield strains.