Abstract:
Experiments were conducted to study plant regeneration through direct somatic embryogenesis using mature zygotic embryo and cotyledonary explants from seeds of Melia volkensii stored for <3 and >12 months. Explants were cultured on Murashige and Skoog (MS) medium supplemented with BAP, NAA and 2,4-D (0.5, 1.0 and 2.0 mg l−1) alone, and BAP (0.5, 1.0, 2.0 and 4.0 mg l−1) in combination with 2,4-D or NAA (0.2 and 0.5 mg l−1). After 4 weeks in culture, up to 60% of cotyledonary explants from the seeds stored for <3 months produced direct somatic embryos on BAP (0.5–4.0 mg l−1) in combination with 2,4-D (0.2 mg l−1). The number of somatic embryos ranged from 5 to 14 per explant in BAP (0.5 mg l−1) and 2,4-D (0.2 mg l−1) combination. Only 20% of cotyledonary explants from seeds stored for >12 months produced somatic embryos. Mature zygotic embryos failed to produce any somatic embryos. Subcultures of somatic embryos from cotyledonary explants of seeds stored for <3 months formed clusters of shootlets on semi solid MS and 1/2 MS media. After 6 weeks of subculture on multiplication MS media augmented with BAP (0.5 mg l−1) and IAA (0.2 mg l−1), 70% of the shoot tips formed 4–7 shoots per explant. Up to 33% of the multiplied shoots were rooted in MS medium supplemented with 2.0 mg l−1 IBA. Plantlets developed normally into seedlings in the greenhouse.
