Ethylene preparation and its application to physiological experiments

Ethylene is the first identified gaseous hormone regulating many aspects of plant growth and development. ACC and ethephon are two widely used chemicals replacing ethylene treatment when ethylene is not available. However, the amount of ethylene converted by ACC and ethephon is not controllable, leaving it questionable whether either treatment can mimic the effects of ethylene for experiments that are sensitive to ethylene concentration, response window, and treatment durations. Ethylene can be chemically made by ethanol dehydration; however, further purification from the dehydration products is needed. We previously reported that the ethylene gas can be easily prepared by decomposing ethephon in a buffered condition and the resulting ethylene can be used directly. Ethylene responses can be estimated by the measurement of the hypocotyl length of etiolated seedlings, or by ERF1 (Ethylene Response Factor1) expression. Although ACC of low concentrations is insufficient to induce ERF1 expression, ACC of high concentrations can replace ethylene for experiments where ethylene treatment is not feasible. However, ACC may undergo early consumption. Versatile approaches were developed so that laboratories lacking ethylene and techniques for gas handling can easily perform necessary ethylene treatments.