Histological study of somatic embryogenesis in saffron (Crocus sativus L.)

Saffron (Crocus sativus L.) is a triploid and sterile plant which is propagated by culture of corms. Somatic embryogenesis in in vitro conditions could be used efficiently in saffron improvement. In this study the pathway of initiation، growth and development of somatic embryogenesis in saffron was studied in ABRII at 2008. At first، the suitable conditions for embryogenesis using apical and axillary corm buds cultured on MS medium containing different levels of 2،4-D and BAP hormones in factorial design based on CRD was tested and optimized. The highest amount of embryogenesis was observed in medium containing 2 mg/l 2،4-D and 1 mg/l BAP. For histological study of embryogenesis، sampling from cultured tissues at various growth stages was done. Study of the prepared slides showed two distinct types of cell in callus tissues. One normal cells with unclear cytoplasm and the other type of cells with relatively dense cytoplasm and thin cell walls (meristematic cells) that after sequential divisions produced a mass of embryonic cells. These cells were appeared on callus surface which in later stages of growth and maturation، produced buds and microcorms.