Plant regeneration from single-nodal-stem explants of legume tree Prosopisalba Griseb

Seeds of Prosopis alba were scarified with abrasive paper and placed to ger minate on MS (Murashige and Skoog 1962) nutrient medium. After 7 days of cu lture, the basal part of cotyledons was removed and pieces of 4 mm" from di stal parts were cultured on Murashige and Skoog (1962) mineral salts and vi tamins (MS) (3% sucrose) supplemented with growth regulators. Callus prolif eration took place in the majority of the media tested. A low percentage of calluses with green buds that developed on MS basal medium containing 0.1 mg. L-1 2,4-D alone or supplemented with BAP at 0.1 mg.L-1 was observed. Ne ither cotyledonary segments in any medium assayed regenerated the whole pla nts. Bud elongation (near 70%) was achieved when single-nodal-stem segments cut from 20 days old seedlings were cultured on MS salts supplemented with 3 mg.L-1 NAA or 3 mg.L-1 IBA combined with 0.05 mg.L-1 KIN after 60 days i n culture. Multiple shoots per bud were also observed. Single-nodal-stem se gments from five-year-old plants were also cultured on the same media used for seedling explants. Maximal frequency of explants with bud elongation (n ear 70%) was found on MS with 0.1 mg.L-1 NAA plus 1 mg.L-1 BAP after 60 day s of culture. Single-nodal-stem explants cut from adult trees (more than 20 years) were also employed, but the number of bud elongation was lesser. Fo r rooting, the elongated shoots were transferred to a semisolid or liquid M S culture medium employing a paper bridge, supplemented with 0.5 mg.L-1 IBA or 0.1 mg.L-1 NAA.