Résumé
Somatic embryogenesis in callus cultures of Commiphora wightii (Arnott.) Bhandari was achieved. Though the frequency of explants producing embryonic culture was low, immature zygotic embryos were the only suitable explants to produce embryonic callus after reciprocal transfers on media containing 2,4,5-trichlorophenoxy acetic acid (0.1 mgl(-1)) and kinetin (0.1 mgl(-1)) or devoid of growth regulators. All other media failed to produce embryonic callus. Embryonic cells were small, densely filled with cytoplasm and isodiametric as compared to non-embryonic cells, which were large, elongated and vacuolated. Maximum growth of embryonic callus was recorded on modified MS medium (MS-2 medium) supplemented with BA (0.25 mgl(-1)) and IBA (0.1 mgl(-1)). MS-2 salts supported higher growth of callus as compared to tissues grown on B5 medium containing same concentrations of plant growth regulators. Exogenous medium nutrients had no effect on somatic embryo development whereas plant growth regulators had little effect. Asynchronously growing embryos formed plantlets regularly which were successfully transferred to the field conditions.
Sujets)
Techniques de culture , SomitesRésumé
An efficient method has been developed for large-scale multiplication of Curculigo orchioides (Hypoxidaceae), an endangered medicinal plant, through direct bulbil formation from leaf explants in shake flask cultures. Leaf-segments (7 x 10 mm) were cultured in B5 liquid medium containing KNO3 (200 mgNL-1), (NH4)2SO4 (50 mgNL-1), benzyl adenosine (2.2 microM), adenine (0.11 mM), indole butyric acid (1.0 microM) and polyvinyl pyrrolidone (250 mgL-1). About 95% of explants produced maximum number of bulbils (546/flask at 6 weeks growth) in the medium. Shake flask cultures yielded 2737 bulbils/L medium whereas static cultures yielded 624 bulbils/L medium. Germination of bulbils was maximum (90.62%) on agar-gelled B5 medium containing benzyl adenosine (2.2 microM) and gibberellic acid (3.5 microM). Plantlets developed in vitro were successfully transferred to soil with a high rate of survivability (90%) and were comparable to natural population in growth and vigour.