Comparison of Early Inflorescence Development between Japanese Pear (Pyrus pyrifolia Nakai) and Quince (Cydonia oblonga Mill.)

Abstract

Japanese pear (Pyrus pyrifolia) and quince (Cydonia oblonga) form different inflorescence architectures, the former forms raceme inflorescence with about eight flowers and the latter forms solitary-flowered inflorescence. We observed the floral differentiation of Japanese pear and quince to clarify the differences in their early inflorescence development. Floral differentiation of Japanese pear occurred in late June. After apical meristem turned to a dome-like structure, inflorescence developed by forming lateral flower meristems in axils of bracts. The apex of inflorescence became the terminal flower meristem, two or three meristems were initiated in axils of outer bracts and leaf primordia, and finally approximately eight flower meristems were formed in the inflorescence. Floral differentiation of quince was initiated from late October to November after eight leaf primordia had been initiated. Apical meristem transformed to a dome-like structure and initiated sepal primordia. Axillary meristems of bracts or leaf primordia in Japanese pear differentiate to flower meristem while those in quince remained undifferentiated to form axillary buds in the following growing season, resulting in an inflorescence architecture difference in Japanese pear and quince.