Clonal propagation of Lomandra longifolia by somatic embryogenesis

• Efficient clonal propagation system through somatic embryogenesis has been developed from floral parts and leaf bass of Lomandra longifolia.
• 2.0 mg L−1 was found to be the optimum concentration inducing organogenic and embryogenic calli.
• Somatic embryo differentiation and plantlet regeneration occurred best on MS basal medium either 2,4-D-free or with 1.0 mg L−1 NAA and 0.1 mg L−1 BAP.
• Anatomical studies provided evidence for plant regeneration via somatic embryogenesis and, most likely, single cell origin of somatic embryos.

A plant regeneration system based on somatic embryogenesis was developed for the efficient clonal propagation of Lomandra longifolia. Cultured leaf-bases, immature inflorescences and immature ovaries of L. longifolia formed embryogenic calli, with subsequent somatic embryo induction upon subculture to Murashige and Skoog (MS) agar medium supplemented with 2.0 mg L−1 2,4-diclorophenoxyacetic acid (2,4-d), 500 mg L−1 casein hydrolysate, 100 mg L−1 myo-inositol, and 30 g L−1 sucrose. Of the three types of explants, immature inflorescences and immature ovaries produced only embryogenic calli, whereas leaf bases produced both embryogenic and non-embryogenic calli. Root tips cultured on 2,4-d-containing media formed a tissue that did not form somatic embryos, but instead differentiated into shoot-buds. Somatic embryo differentiation and plantlet regeneration occurred best from embryogenic calli on 2,4-d-free basal medium or MS basal medium containing 1.0 mg L−1 NAA and 0.1 mg L−1 BAP; and the resultant in vitro-formed plantlets were successfully transferred to soil. Morphological and anatomical data describing development of calli and somatic embryos provided evidence for plant regeneration via somatic embryogenesis and, most likely, single cell origin of somatic embryos.