Somatic Embryogenesis or Shoot Formation Following High 2,4-D Pulse-Treatment of Mature Embryos of Paspalum scrobiculatum

Mature zygotic embryos of Paspalum scrobiculatum L. cv. PSC 1 on MS or N6 nutrient medium supplemented with various concentrations of 2,4-D (4.5 - 22.5 µM) formed embryogenic callus, which differentiated into somatic embryos within 5 weeks of culture. The somatic embryos after transfer to hormone-free regeneration medium germinated and formed plantlets. Of the two nutrient formulations, N6 was relatively better than MS for somatic embryogenesis. A culture for 11 d on 100 µM 2,4-D was essential for the establishment of an embryogenic callus. Shorter duration, 4-d or 7-d culture on 2,4-D medium, supported some proliferation and subsequent differentiation into shoot-buds or multiple-shoots, in high-frequency cultures. This is first instance in monocots of a controlled regeneration response; either somatic embryogenesis or shoot formation.