trans-Cyclooctene, cis, trans-l,5-cyclooctadiene, and cis, trans-l,3-cyclooctadiene have been compared with the cis and cis,cis isomers and with 2,5-norbornadiene for competition with ethylene for binding in mung bean sprouts and tobacco and for action (induction of chlorophyll degradation) in banana . The compounds containing a trans double bond were much more effective in competition for binding and action than the cis and cis,cis compounds . trans-Cyclooctene and cis,trans-1,3-cyclooctadiene were in the general range of 50-90 times more effective than 2,5-norbornadiene . All of the compounds blocked ethylene action .