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In Vitro Studies of Ethephon-induced Abscission in Olive. II. The Relation between Ethylene Evolution and Abscission of Various Organs1

1981; American Society for Horticultural Science; Volume: 106; Issue: 1 Linguagem: Inglês

10.21273/jashs.106.1.19

2327-9788

S. Lavee, George C. Martin,

Plant Surface Properties and Treatments

Abstract Leaves, stems, inflorescences and fruits from excised ‘Manzanillo’ shoots of olive ( Olea europaea L.) basally fed with (2-chloroethyl)phosphonic acid (ethephon) were used to study the relation between ethylene evolution and abscission. The abscission response of the various organs to ethephon was directly related to concentration and length of exposure to a given treatment concentration. After an ethephon pulse treatment, stem tissues evolved increased levels of ethylene for a longer period than leaves, whereas the effect on petioles was shorter than leaves. Leaf abscission occurred after ethylene evolution from them declined. Inflorescences did not abscise even though induced to evolve high levels of ethylene. The rate of leaf ethylene evolution and abscission was higher in reproductive shoots than in nonreproductive shoots and was influenced by the number of inflorescences present on the shoot. Leaves on shoots with a large number of inflorescences senesced more rapidly than those with fewer inflorescences in our in vitro system and developed a marked chlorosis after 24 hours. Ethylene evolution from fruits on ethephon-fed shoots was low and abscission was erratic. The abscission layer between fruit and stem developed at no specific site along the pedicel or peduncle. Probable reasons for the specific levels and duration of ethylene evolution from the various tissues after an ethephon pulse are discussed.