关键词: 百合, 分生结节, 类体细胞胚, 体细胞胚

Abstract: Petioles of lily were used as explants to induce primary nodular callus. Then，somatic embryo-like structures were induced from the primary nodular callus and somatic embryos were induced from the proliferated nodular callus，a systematic morpho-histological study was conducted for showing the differences of the two regenerated structures by microscope observation and paraffin section analysis. The somatic embryo-like structures were globular to oval-shaped or similar to shoots，and consisted of parenchymatous cells. Histological observations indicated their connection with the maternal tissue by evident vascular strands and the existence of multiple vascular centers during morphogenesis. These structures closely resembled somatic embryos in appearance. Somatic embryos derived from the newly embryonic callus situated at the surface of the proliferated nodular callus，and the early-stage somaticembryos were formed by embryonic cells. Somatic embryo grew into a complete plantlet after passing through globular，oval and cotyledonary-shaped stages. Histological observations did not reveal any vascular connections with the maternal tissue during the whole development process. Moreover，the shoot pole and root pole of them appeared simultaneously，their connection was built up through a single vascular bundle. Therefore，even much similar appearance between the two regenerated structures，their development manners and organizational structures totally differ.

Key words: lily, nodular callus, somatic embryo-like structure, somatic embryo