One of the major applied biocide in the cut flower market and industry is hydroxy quinoline citrate (HQC). This compound is the most recommended biocide for cut rose flowers. Beside its ethylene inhibiting behavior, its major function is to control microbial proliferation and consequently improve cut flower water relation. Beside microbial proliferation control, biocides could affect cut flower’s quality and physiology in various aspects. In order to study HQC impact on various microbial and physiological aspects, ‘Cherry Brandy’ roses were treated with HQC (200, 300 and 400 mgl-1) and sterilized distilled water (control). As a result, effects of HQC application as vase solution biocide and its impact on vase life, water relation, vase solution microbial kind and population beside different physiological parameters such as chlorophyll degradation, chlorophyll fluorescence and membrane permeability were investigated during this study. Results indicated that HQC significantly reduces vase life of ‘Cherry Brandy’ rose flowers compared to control. This is while all concentrations of this compound completely prevented microbial proliferation in vase solutions. On the other hand its low concentration application improves fresh weight gain and solution uptake during the first week of vase life. Although this compound did not have a visual and serious side effect, but it declined leaf membrane permeability and chlorophyll fluorescence of the treated flowers. Controversially chlorophyll content of HQC treated flowers increased during vase life.
