title: Dispersal and size fractionation of embryogenic callus increases the frequency of embryo maturation and conversion in hybrid tea roses.
abstract: Plant regeneration from embryogenic cells of two Rosa hybrida cultivars, Kardinal and Classy, was increased by dispersing embryogenic callus in liquid medium for 3 h followed by size-fractionation to isolate proembryogenic masses that were smaller than 530 microm. Dispersed callus of three cultivars, Kardinal, Classy, and Tineke, produced 61-135 cotyledonary-stage embryos/100 mg fresh weight (FW) as compared to intact callus that had not been dispersed, which produced only zero to three cotyledonary-stage embryos/100 mg FW. Over 500 cotyledonary-stage embryos/100 mg FW callus developed from proembryogenic masses of Kardinal, Classy, and Tineke following 2 months of culture on solidified Murashige and Skoog's basal salts medium supplemented with 0.25% activated charcoal. Cotyledonary-stage embryos of Classy that developed from both dispersed callus and fractionated cells of various sizes showed a significantly higher conversion frequency to plants (28%) than cotyledonary-stage embryos isolated from intact callus (9%). The highest conversion frequencies for Kardinal (50-58%) occurred from cotyledonary-stage embryos that developed from dispersed callus and from the fraction of cells smaller than 850 microm.
authors.affiliation: U.S. Department of Agriculture, U.S. National Arboretum, Floral and Nursery Plants Research Unit, B-010A Room 238, BARC West, Beltsville, MD 20705, USA. Kamok@ba.ars.usda.gov
authors.forename: K
authors.initials: K
authors.lastname: Kamo
authors.forename: B
authors.initials: B
authors.lastname: Jones
authors.forename: J
authors.initials: J
authors.lastname: Castillon
authors.forename: J
authors.initials: J
authors.lastname: Bolar
authors.forename: F
authors.initials: F
authors.lastname: Smith
mesh_terms: D018548:Cotyledon / Q000254:growth & development; D003470:Culture Media / Q000494:pharmacology; D046508:Culture Techniques; D012038:Regeneration; D027826:Rosa / Q000196:embryology* / Q000254:growth & development; D012639:Seeds / Q000254:growth & development*
chemical_list: D003470:Culture Media