Correlations among Petal Color, pH, and Epidermal Cell Morphology of Ornamental Crabapple

  Objective   Correlations among the color, pH, and epidermal cell morphology of petals of ornamental crabapple flowers were preliminarily analyzed.

  Method   Colors of the petals of 14 varieties of white, reddish purple, pink, and dark-purple crabapples at blooming, big-bud, full-bloom, and end florescence stages were measured by RHSCC and a chromatic meter. Morphology of petal epidermal cells was examined under a scanning electron microscope. Correlations among these properties were statistically analyzed.

  Result  The white and pink lines of crabapples had a petal pH ranging from 5.24 to 6.37, while the dark-purple and reddish purple lines, from 4.98 to 5.53. In general, the pH declined as the color turned from light or white to dark or reddish purple and the colorimeter red-green a^* and saturation C^* measurements increased. A similar trend was also observed during the flowering process. Aside from the dark-purple variety, the other 3 crabapple series had petal epidermal cells of varied types and, in florescence, the cells became more noticeably flattened as the petal color faded.

  Conclusion  There appeared to be correlations among the pH of petals and the formation and fading of flower color on the 14 ornamental crabapple varieties. The petal epidermal cell morphology did not significantly correlate to the flower color phenotype but possibly to the color fading in florescence of the plants.