Multiple regeneration pathways in Spathoglottis plicata Blume — A study in vitro

Abstract

Asymbiotic germination of immature seeds (embryos), and mature seeds and micropropagation of Spathoglottis plicata were described. Effects of three nutrition media namely, Murashige & Skoog (MS); Phytamax (PM); and Phyto-Technology orchid seed sowing medium (P723), two carbon sources such as glucose and sucrose at 2–3% (w/v), two plant growth regulators such as 6-benzylaminopurine (BAP; 0.5–3.0mgl−1) and α-naphthalene acetic acid (NAA; 0.5–2.0mgl−1) and peptone (2.0gl−1) were examined on seed germination, early protocorm development and micropropagation. The maximum germination of mature seeds (95%) was recorded in PM medium supplemented with 2% (w/v) sucrose+2.0gl−1 peptone. For germination of embryos P723 medium supplemented with 1.0mgl−1 BAP proved best. Multiple shoot buds or protocorm-like bodies (PLBs) were produced from stem segments of in vitro raised seedlings. Both direct organogenesis and embryogenesis were observed and the morphogenetic response was initiated by different concentrations and combinations of PGRs. The optimum PGR combination for maximal PLB regeneration was 1.0mgl−1 NAA+2.5mgl−1 BAP, while 1.0mgl−1 NAA+1.0mgl−1 BAP for shoot bud development. Strong and stout root system was induced in half strength PM medium supplemented with 0.5mgl−1 IAA. The well-rooted plantlets were transferred to pots containing a potting mixture composed of saw dust, coconut coir, humus, and coal pieces at 1:1:1:2 (w/w) with 80% survival in outside environment and flowered after two years of transfer.