Plantlet regeneration from mature zygotic embryos and embryonic explants of masson pine (Pinus massoniana Lamb.)

Abstract

Excised zygotic embryos, cotyledons and hypocotyls of juvenile seedlings of masson pine were grown on DCR medium supplemented with several concentrations of various plant phytohormones. BA (1.0 mg/ L) in combination with NAA (0.05 mg/L) in DCR medium was found to increase the formation of adventitious buds from mature zygotic embryos, but most of them were formed at the tips of embryonic cotyledons. Adventitious buds were obtained from cotyledons and hypocotyls from juvenile seedlings when they were cultured on DCR medium containing BA 3-5 mg/L and NAA 0.1-0.2 mg/L. Elongation of buds were observed on hormone-free DCR medium with or without activated charcoal (0.5%). Root initiation was achieved with full or half strength DCR medium supplemented with IBA 1.0 mg/L and NAA 0.25-0.5 mg/L. Approximately 11-20 axillary buds formed on each explant when juvenile seedling explants were treated (3-20 h) with BA 50-100 mg/L, followed by transfer to hormone-free DCR medium. The maximum number of shoots obtained per explant within six months was 33.