Research Tool: Ethylene Preparation: Treatment with Ethylene and Its Replacements

Abstract

Ethylene gas is an important plant hormone that can be chemically prepared or biologically synthesized by microbes and plants. The gas can be commercially obtained in a pressurized gas cylinder or chemically prepared with necessary purifications. Laboratories that wish to perform experiments involving ethylene treatment need a convenient setup for ethylene preparation and delivery. When the use of a pressurized ethylene gas cylinder is not feasible, an ethylene response can be initiated in the plant or plant organs by treating the plant or organ with an aqueous solution of the natural plant precursor to ethylene, 1-aminocyclopropane-1-carboxylic (ACC), or 2,4-dichlorophenoxyacetic acid (ethephon), which decomposes slowly to make ethylene at a pH above 4.0. However, the release of ethylene for these applications is dynamic and not experimentally controllable, and, moreover, the replacement may produce unwanted side effects that can affect data interpretation. Therefore, a direct ethylene treatment is often favorable over the replacement. An alternative to a pressurized tank of ethylene is the chemical synthesis of ethylene by ethanol dehydration or ethephon decomposition, with a specific setup to collect the produced ethylene. This chapter discusses the advantages and disadvantages of direct ethylene treatment using ethylene gas or a replacement. Also discussed are the underlying chemical and biochemical reactions for ethylene production, and the setup for ethylene treatment in a closed system or a flow-through system. The goal is to provide readers with the necessary tools for ethylene treatment with easily accessed laboratory devices.