The present invention relates to new delivery systems for cyclopropenes in which compositions comprising the cyclopropene and a molecular encapsulation agent complex further comprise additional components which provide slow release of the cyclopropene from the molecular encapsulating agent with water, or release of the cyclopropene from the molecular encapsulating agent with only small amounts of water, or both. The present invention also provides methods to release a cyclopropene from such compositions as well as methods to deliver a cyclopropene compound to a plant to inhibit an ethylene response in the plant.