Rose tissues of different varieties were transformed using a Bio-Rad Helios hand-held biolistic gun, Parameters for optimum transient expression were optimined and included rose variety. flower age, tissue, gold particle size and DNA Loading ratio smooth flowers without thick layers and young unopeaed actively growing flowers were found to be better suited for the transient expression assays The DNA amounts. gold particle amounts and size etc were not found to influence the efficiency of the transient transformation in these tissues. These studies indicate biolistic transformation using hand-beld guns can be used for successful transient expression assays in rose flower tissues. This is especially useful for a quick and easy analysis of genes and their expression before attempting stable transformation. C 2011 SAAB Published by Elsevier BV. All rights reserved.