Regeneration of a metal tolerant grass Echinochloa colona via somatic embryogenesis from suspension culture

An efficient protocol was developed for in vitro plant regeneration via somatic embryogenesis from cell suspension cultures of metal tolerant grass Echinochloa colona (L.) Link. Callus was obtained by culturing leaf base on MS medium supplemented with 0.5 mg dm^-3 of 6-benzylaminopurine (BAP) and 2.0 mg dm^-3 of 1-naphthaleneacetic acid (NAA). Cell suspensions were initiated and established in MS liquid medium containing 0.5 mg dm^-3 BAP, 1.0 mg dm^-3 NAA and 2.0 mg dm^-3 2,4-dichlorophenoxyacetic acid (2,4-D). A reduction in the concentration of 2,4-D to 0.5 mg dm^-3 induced formation of somatic embryos. The embryos developed and grew into normal plants in the presence of half strength MS medium without growth regulators. The regenerated plants were hardened in the greenhouse and subsequently grown in the open. This system may be also used for isolation and culture of protoplasts as a first step in somatic hybridization. This revised version was published online in July 2006 with corrections to the Cover Date.