The compound represented by formula (IV) or a salt thereof has an inhibitory action on an abscisic acid receptor. The compound or the salt thereof can be used as a plant growth regulator. wherein X is an ethylene group, an ethenylene group or an ethynylene group, R 1 is a hydrogen atom, a phenyl group or a naphthyl group, and the phenyl group and naphthyl group each optionally have a substituent selected from the group consisting of a halogen atom, a hydroxyl group, a C1-6 alkyl group, a C1-6 alkyl group substituted with a halogen atom, a C1-6 alkoxy group, an acetyl group, an amino group, an acetylamino group, a phenyl group and a pentafluorosulfanyl group.
