Abstract:

Low efficiency of somatic embryogenesis and asynchronous embryo development brings a lot of difficulties to the physiological, biochemical, and molecular biological studies of embryogenesis processes in cotton. In the present study, a simple and efficient method was developed to improve somatic embryogenesis frequency and synchronous development of mass somatic embryos from cultured cells of Gossypium hirsutum cv. Coker 201. The embryonic calli obtained after several rounds of subculture were scattered in liquid medium by shaking for 2 d and then resuspended in the same liquid medium after discarding the larger callus aggregates over 30 mesh-size-sieve. The suspensions cultured for 14 d were filtered through 50 mesh-size-sieve and then the aggregates over the sieve were inoculated onto the surface of Whatman filter paper placed on the solid medium containing 2.46 mmol L^-1 IBA and 0.70 mmol L^-1 kinetin to culture for 21 d followed by subculturing. The somatic embryo amount obtained by using new system was 15.5-fold higher than that by suspension culture and 3-fold higher than that by solid culture (without filter papers) at the same culture period, and in the different stages of somatic embryo development, 70.2% for globular, 52.3% for torpedo-shaped and 73.0% for cotyledonary embryos were obtained respectively during the culture. Suspension culture combined with solid culture with filter paper were considered to be beneficial for synchrony of somatic embryogenesis and mass embryo development.

Key words: Cotton, Somatic embryogenesis, Synchronization control, Culture system