Cherry Fruit Abscission: A Role for Ethylene in Mechanically Induced Abscission of Immature Fruits1

Abstract

Abstract Mechanical injury to the seed of immature sour cherry (Prunus cerasus L., cv. Montmorency) fruit caused an immediate and marked increase in ethylene evolution followed by abscission of the fruit at the peduncle: pedicel zone. Ethylene evolution was induced when the seed, but not the pericarp, was injured. The magnitude of ethylene evolution was related to stage of fruit development at time of injury, and was most pronounced when the nucellus was the dominant tissue in the seed. Ethephon (500 and 1000 ppm) also caused immature fruits to abscise and abscission was preceded by embryo abortion. The site of ethephon-induced fruit separation differed depending on stage of fruit development at time of treatment. Fruit separation occurred at the peduncle:pedicel abscission zone when immature fruits were treated, and at the pedicel fruit zone when mature fruits were treated. The role of ethylene in the abscission of immature sour cherry fruit is discussed.