Concentration of 1-methylcyclopropene and the duration of its application affect anti-ethylene protection in Phalaenopsis

Moth orchids (Phalaenopsis spp.) have become the world's most important potted flower crop. Flowers of Phalaenopsis are sensitive to ethylene, and 1-methylcyclopropene (1-MCP) pretreatment enables flowers to withstand ethylene stress. In this study, we investigated effects of 1-MCP concentration and duration of 1-MCP treatment on the protective effect in Phalaenopsis flowers. Pretreating potted Phalaenopsis amabilis with a 1-MCP concentration of as low as 0.005 μL L−1 reduced the flower wilting percentage, indicating that as long as there is 1-MCP protection, the rapid wilting of flowers caused by ethylene can be delayed. However, in order to achieve absolute protection, the minimum concentration required was 0.1 μL L−1. Pretreatment with 0.1 μL L−1 1-MCP for 12 h gave Phalaenopsis plants absolute protection such that the flowers were unaffected even when exposed to artificially high ethylene concentrations of up to 20 μL L−1. The duration of 1-MCP pretreatment could substantially be reduced. A 0.5-h treatment was sufficient when the concentration of 1-MCP was increased to 0.2 μL L−1. The results obtained above were then further confirmed on seven commercial cultivars, where 0.1 μL L−1 1-MCP treatment for 1 h was sufficient to achieve absolute protection against ethylene damage.

► 1-MCP can protect blooming Phalaenopsis plants against ethylene damage.
► Minimum concentration and duration of 1-MCP treatment required for Phalaenopsis was unknown.
► Treating with 0.1 μL L−1 1-MCP for 1 h was enough for absolute protection against ethylene.
► The above finding was verified in seven commercial cultivars.
► Treatment duration can be cut further to 0.5 h, but 1-MCP level needs to be raised to 0.2 μL L−1.