Antimicrobial effect of chlorine dioxide on vase life of cut rose 'Beast'

This study was conducted to investigate the antimicrobial effect of chlorine dioxide (ClO²) on the vase life of cut rose 'Beast' (Rosa hybrida L.). Postharvest treatments to extend the vase life of cut roses were divided into two: holding solution treatment and pulsing solution treatment. In holding solution treatment, the cut roses were treated with preservative solutions containing tap water (TW, control), distilled water (DW), ClO₂ 2, 4, 6, and 8 μL·L ^-1, and compared with a commercialized antimicrobial compound of 8-HQS 200 μL·L^-1. In pulsing solution treatment, cut roses were dipped into the ClO₂solutions of 50, 100, 150, 200, and 250 μL·L^-1for 60 seconds and were placed in DW. The air temperature was 18.4°C, RH 51.5%, and light (photosynthetically active radiation, PAR) 3.6 μmol·m^-2·s^-1with 12 hour day length. The longest vase life of cut roses was observed in the holding solution with ClO₂4 μL·L^-1as 13.8 days and pulsing with 200-250 μL·L^-1as 13.5-13.7 days, where vase life were extended four days longer than TW. Whereas, the inclusion of 8-HQS 200 μL·L^-1in vase solution resulted in phytotoxicity.The relative fresh weight and water uptake have similar tendencies. Bacteria inhibition by ClO₂and 8-HQS were very effective. But bacteria at TW and DW treatments on cut flower with stem were detected in 3.7 × 10⁵CFU·L^-1and 6.3 × 10⁵CFU·L^-1, respectively (without stem in DW 1.4 × 10⁴CFU·L^-1). The ClO₂contents in holding solution of all treatments were scavenged in two-four days after treatment. This study indicated that ClO₂4 μL·L^-1holding solution treatment and 200-250 μL·L^-1pulsing solution treatment can be applied to extend the postharvest life of cut roses.