Establishment of cell suspension cultures and plant regeneration in halophytic Leymus chinensis (Trin.)

The establishment of cell suspension culture from the callus of the halophytic Leymus chinensis (Trin.) LcWT07 line and plant regeneration from suspension-derived callus are described in this study for the first time. Solid medium containing Murashige and Shoog (MS) basic salt, 2,4-dichlorophenoxyacetic acid (2,4-D, 2.0 mg l^-1), and L-glumatic acid (5.0 mg l^-1) induced the highest rate of cell division among various solid media with various concentrations of 2,4-D, with good distribution of different mature seeds derived-callus types. Liquid medium with the same hormone distribution was therefore, used for cell suspension culture of L. chinensis. A slight increase in relative water contents was observed in suspension-derived callus than Type 1 callus, but not Type 2 to 4 calli. Over a 30 d-suspension culture, high growth rates were observed, and great amounts of biomass were accumulated, with 71.07% average daily increment and 22.32-fold total fresh weight increment. The potential of plant regeneration was induced on solid medium containing MS basic salt, 0.2 mg l^-1 α-naphthalene acetic acid (NAA), 2.0 mg l^-1 kinetin (Kn), and 2.0 g l^-1 casamino acid, with faster somatic embryogenesis than that using Type 1 callus. Rooting of all regenerated shoots was successfully performed on half-strength MS medium. This procedure provide basis for morphological, biochemical and molecular studies of the nature of somatic embryogenesis from single cell to whole plant, and shorten the process of somatic embryogenesis.