Effects of STS and 1-MCP on Flower Opening and Lifespan of Potted Kalanchoe blossfeldiana Exported to Japan

This study was conducted to determine the effects of silver thiosulfate (STS) and 1-methylcyclopropene (1-MCP) on flower opening and lifespan of potted Kalanchoe blossfeldiana 'Oriba' for exportation. Ethylene inhibitors, STS and 1-MCP were applied to the kalanchoe plants prior to their export to Japan. STS 0.5 mM with 1% Tween 20 surfactant was directly sprayed (20 mL per plant) to leaves, buds, and flowers and 1-MCP 100 $nL{\cdot}L^{-1}$ was injected into sealed glass chambers containing kalanchoe plants, which were placed on the chambers for 6 hours. After transport to Japan, the plants were immediately transferred to a simulated retail condition room (80 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ for 12 hours of photoperiod at $22^{\circ}C$ and 64% RH) at Toyko University. The numbers of buds, open florets, and wilted florets in the middle inflorescence for each plant were counted right after export, 1 week after export, and 6 weeks after export. The percentages of open florets and wilted florets were calculated from the numbers. STS treatment resulted in 35% more open florets than the control and only 11% of wilted florets at 6 weeks after export to Japan which indicate the extension of lifespan of potted kalanchoe plants. Meanwhile, the plants exposed to 1-MCP before export did not show any significant differences in the numbers of buds and open florets and the percentages of open and wilted florets compared to control plants. In conclusion, STS 0.5 mM treatment strikingly induced better opening florets and lifespan of kalanchoe plants from 1 week to 6 weeks after export than control.