Flower Bud Differentiation and Development of ‘Jinsi No.4’ Jujube (Ziziphus jujuba Mill.) in Hunan Province of Southern China

Ziziphus jujuba Mill. is one of the most important fruit crops and has been cultivated in China for more than 4000 years. Z. jujuba fruit is rich in nutritional and medicinal values. Compared to other wood fruits, Z. jujuba is unique in its flowering and fruiting characteristics. Floral buds differentiation and formation of Z. jujuba is an essential process that affects yield. Z. jujuba ‘Jinsi No.4’ blooms profusely, yet its final yield is low. In this study, the floral bud differentiation and development of ‘Jinsi No.4’ were examined by paraffin section. Results showed that the floral buds of ‘Jinsi No.4’ differentiated in the current year and started from early April. The duration of a single flower differentiation was short, taking only 7 days for maturation of flowers buds. Floral bud differentiation of ‘Jinsi No.4’ can be divided into six stages, i.e., pre-differentiation, initial differentiation, sepal differentiation, petal differentiation, stamen differentiation, and pistil differentiation. Flower development experienced seven stages, i.e., alabastrum, alabastrum break, sepal flattening, petal flattening, stamen flattening, filament withering, and ovule swelling. Dysplasia was observed in some floral organs in Z. jujuba ‘Jinsi No.4’, suggesting that the dysplasia of floral organs may be one of the main reasons for low yields. Our findings on flower bud development in ‘Jinsi No.4’ will contribute to its production and flowering management in Hunan area of southern China.