Direct as well as indirect somatic embryogenesis from immature (unemerged) inflorescence of a minor millet Paspalum scrobiculatum L.

Somatic embryos differentiated directly on the rachis of immature inflorescences of Paspalum scrobiculatum L. cv. PSC 1 on culture to MS or N₆ medium supplemented with different concentrations (4.5–22.5 μM) of 2,4-dichlorophenoxyacetic acid (2,4-D). Direct embryogenesis on the rachis of inflorescence explants forms the first instance in graminaceous plants. Highest frequency of direct embryogenesis (34%and 30% cultures, respectively) was possible on N₆ medium supplemented with 4.5 μM of 2,4-D and MS medium fortified with9.0 μM of 2,4-D. Other tissues of the explant, floral-primordia, only after an initial phase of callusing differentiated into somatic embryos; indirect embryogenesis. Somatic embryogenesis, direct as well as indirect, was resolved by scanning electron microscopy. The somatic embryos germinated and developed into plantlets on regeneration medium. Interestingly, one week incubation of somatic embryos on activated charcoal (0.5%) fortified basal medium, supported high potential for ‘germination’ on transfer to charcoal-free basal medium. This beneficial effect of activated charcoal on regeneration of somatic embryos into plantlets is the first record in the Gramineae. [ABSTRACT FROM AUTHOR]