Modified Atmosphere (MA) and 1-Methylcyclopropene (1-MCP) Combination Treatment Extends the Postharvest Life of Carnations

Abstract

The effects of modified atmosphere (MA) and 1-methylcyclopropene (1-MCP) on the quality and longevity of florets were investigated in potted carnation ‘Scarlet’. MA with and without 1 μL·L⁻¹ 1-MCP (2 day-exposure) for whole plant at 22/17°C significantly delayed the peak of ethylene and wilting of florets, and prolonged the display life from 7.0 to 9.4 days after harvest (DAH). In the experiment for cut florets, active MA (a-MA; initial gas, 2.75% for CO₂ and 11.5% for O₂) for 2 days prolonged the longevity from 5.5 to 7.8 days, whereas a-MA in combination with the 1-MCP (a-MA/MCP) treatments prolonged longevity to 12.5 days. Maximum ethylene production was decreased from 58.3 to 9.8 nL·g⁻¹·h⁻¹ by a-MA, while only trace amounts was detected in a-MA/MCP. In the gynoecium, a-MA repressed DcACS2 (1-aminocyclopropene-1-carboxylate synthase) expression throughout the experiment and DcACS3 until 4 DAH. The a-MA also repressed DcACO1 (ACC oxidase) until 6 DAH, whereas a-MA/MCP completely repressed DcACO1. In the petals, a-MA/MCP repressed DcACS2 and DcACS3. The both treatments significantly lowered respiration rate of florets on 8 DAH, and increased contents of soluble carbohydrates in petals on 4 DAH. These results indicate the combination of MA and 1-MCP is more effective than MA alone in the reduction of ethylene production, respiration and the expressions of DcACS2 and DcACO1, and maintained soluble carbohydrates, and thus improved postharvest qualities compared to the single treatments.