A simple sustained release device for the ethylene binding inhibitor 1-methylcyclopropene

Abstract

The efficacy of 1-methylcyclopropene (1-MCP) gas to prevent the adverse effects of ethylene is limited by its short-term residual activity in some plants. Development of a simple 1-MCP sustained release device that prolongs 1-MCP exposure is reported herein. Sustained release devices comprised of polyvinylchloride tubes containing 0.1 g SmartFresh™ powder (a.i. 3.3% 1-MCP) and 1.25 ml deionised water were used to release 1-MCP into fibreboard cartons containing cut Geraldton waxflower (Chamelaucium uncinatum Schauer) cv. CWA Pink bunches during export shipment by air (107 h) from Australia to the UK. The devices protected flowers against abscission induced by subsequent test exposures to ethylene (10 μl l−1, 12 h, 20 °C) for 3–5 days after arrival. In contrast, pre-shipment treatments with either a single application of 790 nl l−1 1-MCP for 14 h at 2 °C or a 0.2 mM Ag+ (as silver thiosulphate; STS) pulse for 14 h at 2 °C protected flowers against exogenous ethylene for only 1–2 days of post-export life. However, pre-shipment 1-MCP fumigation was up to about three-fold more effective than either sustained 1-MCP release or pre-shipment STS treatments in reducing floral organ and leaf abscission from bunches during export. Thus, it is suggested that a combination of pre-shipment 1-MCP fumigation before export with sustained 1-MCP release during shipment should maximise efficacy against ethylene-induced waxflower flower abscission.