Effect of Ethylene Source on Abscission of Pepper Plant Organs

Abstract Ethylene-induced abscission of pepper ( Capsicum frutescens L. cv. Hungarian Hot Yellow Wax) flower buds, leaves, and fruit depended on ethylene source (i.e. ethylene gas from a compressed gas source vs. ethylene released from Silaid) and concentration. In response to ethylene from either source, flower buds and small fruit (< 10 mm long) abscised most readily and fully expanded leaves least readily. Concentrations of Silaid that induced fruit abscission comparable to a given concentration of ethylene gas induced significantly greater leaf abscission than ethylene gas. Application of Silaid at dusk resulted in a small, but significant, increase in abscission relative to early morning application. Progressive increases in temperature between 18° and 32°C enhanced fruit and leaf abscission in response to ethylene gas. Abscission mediated by ethylene gas was not affected by light intensities between 120 and 300 µmol·m –2 ·s –1 PAR. Chemical name used: (2-chloroethyl)methylbis(phenyImethoxy)silane (Silaid, CGA-15281).