INDUCED SOMATIC EMBRYOGENESIS UNDER OSMOTIC STRESS IN Bouteloua curtipendula (Michx.) Torr., A RECALCITRANT APOMICTIC SPECIES

Abstract

Several basal MS culture media added with different auxins were tested on induced calli to promote normal plant regeneration, using mature caryopsis of sideoats grama Bouteloua curtipendula (Michx.) Torr. as explants. The induction media was supplemented with 2,4-diclorophenoxiacetic acid and several cytokinins. Basal MS + 2,4-D + BAP media supplemented with sorbitol (MI-13, MI-14) produced morphologically-viable regeneration calli. Potential highly embryogenic calli obtained from MI-14 were placed on different regeneration media. Medium MR-2 induced the highest plant regeneration frequency (95.8 %) as well as conversion efficiency (13.9 %). Green morphologically-normal plants were obtained on supplemented media added with kinetin (1 mg L^-1), naphtalenacetic acid (0.2 mg L^-1), and giberellic acid (0.2 mg L^-1). Osmotic stress or hormonal balance due to sorbitol addition produced pro-embryo within soft calli and induced somatic embryos in sideoats grama. This is the first report of a plant regeneration protocol for this apomictic species.