The three growth regulators ( paclobutrazol , ethrel and kinetin ) differently affected the vegetative growth , chioroplast pignients , endogenous hormones and root fresh weight of the two ornamental plants ( Chlorophirnn comosum and Pepromia clustiifolia ) As for growth paclobutrazol and ethrel decreased the height of’ the plants while kinetin led to it’s increase . Shoots fresh weight was significantly increased by the all growth regulator treatments . Kinetin significantly increased leaf area in the two plant types ‘hi le ethrel increased this parameter iii Chlorophirnn c omosum and decreased it in Peprona clustiifolia . On the other hand , paclobutrazol significantly decreased leaf area in the both plant types . The three growth regulators generally increased the chloroplast pigments . Paclobutrazol was the most effective in this respect Paclobutrazol highly increased the root fresh weight followed by ethrel then kinetin in both plant types Paclobutrazol application decreased the endogenous content of gibberellin-like substances that cause the shortening of the plant height . Besides , ethrel treatment markedly increased the endogenous conteilt of cytokinin-like substances that is why new suckers and branches were originally stimulated