Leaf Color and Pigments of 48 Ornamental Crabapple Germplasms Leaves

  Objective  Variations in color and pigments on leaves of ornamental crabapple germplasms in season were used to classify the plants for establishing an evaluation system for landscaping.

  Method  Luminosity L*, saturation C*, and hue angle h° as well as pigments in the upper, middle, and lower parts of the leaf of 48 ornamental crabapple germplasms were measured using a colorimeter and a spectrometer.

  Results  ① The color measurements on all crabapple varieties in June distributed in the CIELCH space more concentrated in the upper part and gradually lessened toward the lower part of a leaf. The color was richer and the loci more scattered in the upper part as well. ② The relative contents of anthocyanin and carotenoid decreased, but that of chlorophyll increased, from the upper to the lower leaf. ③ The germplasms clustered by leaf color were classified into the green Group A that included bright green A₁ and dark green A₂, the brown Group B, and the red Group C that included reddish brown C₁ and reddish purple C₂.

  Conclusion  Of all crabapple groups, Group A₁ had a high relative chlorophyll content displaying bright green foliage; Group B had significantly varied color measurements and a significantly higher carotenoids content than the other groups making it suitable for breeding programs; and Group C₁ had a high anthocyanin to chlorophyll ratio of （1.22±0.24） and an h° of (29.74±4.74)° rendering it the choice of a showy red-leaf crabapple variety.