Multiple Pathways of Somatic Embryogenesis at a High Frequency in Asparagus officinalis L.

Abstract

An experimental system of somatic embryogenesis at a high frequency has been established in Asparagus officinalis L. The best medium for asparagus somatic embryogenesis was MS medium. Sucrose was found to be the best carbon source. Optimum combination of phytohormones was 0.5mgl^-1 2, 4-D with 1.0mgl^-1 BA. More than 80% of the culture cells developed into somatic embryos when MS medium supplemented with 0.5mgl^-1 2, 4-D, 1.0mgl^-1 BA and 20gl-1 sucrose was used. Interestingly, heart-shaped and mature embryos with two cotyledons, which are the typical structures of dicotyledonous embryos, were observed in this system although asparagus is a monocotyledonous species. Complete plants were regenerated from the mature embryos with one or two cotyledons at a frequency over 50%. On the basis of these results, multiple pathways of somatic embryogenesis in asparagus were proposed.