Morphological studies on direct regeneration of floral buds from in vitro cultures of sepal segments in Sinningia speciosa hiern

The morphological changes in the cultures of sepal segments in Sinningia speciosa Hiern were observed with Zeiss Stemi 2000-C Stereomicroscope from 0 to 65 days after culture in vitro. The light yellow globular protuberances were observed on the cut edge and the surface of sepal segments after culture for 24 days. Then the globular protuberances grew bigger gradually. A lot of floral buds on the surface of sepal segments formed after culture for 60 days. The morphological changes in the cultures of sepal segments were studied with light microscopy after culture for 0 to 30 days as well. The cells of tissues of sepal segments arranged regularly and no dividing cell was observed on the first day culture. There appeared some small meristematic centers of dividing cells on cut edge and the lower epidermis on the 7th day after culture. To the 20th day culture in vitro, the floral organ primordia were differentiated on the cut edge. On the 30th day culture, floral buds with petal, stamen primordia were observed. In addition, the morphological changes in the cultures of sepal segment were studied during the 14 to 30 days culture with scanning microscopy as well.