Somatic embryogenesis and plant regeneration in Zizyphus jujuba Mill in vitro

The method of direct somatic embryogenesis was developed and conditions of regeneration in Chinese date (Zizyphus jujuba Mill.) in vitro were studied for the first time. The greatest number of somatic embryos were obtained on the half-strength MS nutrient medium supplemented with 2,2 mu M 2,4-D. Optimum sizes of primary explants were determined for three genotypes of Chinese date. In darkness, at 26 degrees C, the frequency of embryogenesis was 90%. In the course of culturing, secondary embryoids were formed on the developed nonzygotic embryos. Histological analysis points to the induction of somatic embryogenesis, which resulted in the formation of bipolar structures of embryoids. The regeneration of plants was conducted on the modified Pierik medium without hormones. Miniature plants were adapted in vivo.