PRELIMINARY-REPORT ON THE DIRECT REGENERATION OF ADVENTITIOUS BUDS ONLEAF EXPLANTS OF IN-VIVO GROWN GLASSHOUSE ROSE CULTIVARS

Direct regeneration of adventitious buds was studied on different leaf explants taken from five glasshouse-grown cut were disinfected, divid ed into six types of explant that were inoculated on half-strength sol id MS medium, completed with 6.8 mu M TDZ and 0.27 mu M NAA. Adventiti ous buds emerged 14-17 days after inoculation. Highest percentage of r egeneration occurred at the base of leaflets (70-100 %) or at the base of leaf sheaths (25-100 %). Genotypic variation for parameters of reg eneration is probable. AgNO3 significantly reduced the time to adventi tious bud emergence (14.3 vs. 17.1 d) and promoted the percentage (91 vs. 62 %) of regenerating explants. The use of glasshouse-grown plants , polarity of regeneration, and the probable occurrence of ethylene ar e discussed. Direct regeneration is compared to somatic embryogenesis.