Endogenous gibberellins and abscisic acid-metabolites: their role for during flower bud abscission and embryo development in pistachio

Authors: MUHAMMET ALİ GÜNDEŞLİ

Abstract: This study was carried out to determine the effect of different growth periods and possible role of gibberellins (GAs) and abscisic acid (ABA) metabolites on the alternate bearing of the pistachio (Pistacia vera L.). For this purpose, the levels of GAs and ABA in the panicles and nuts of the trees during flower bud abscission and embryo development were analyzed in the crop "on" year. The results showed significant differences and changes in ABA and GAs among the tissues and periods investigated. Dihydrophaseic acid (DPA) and GA₁₉ were the dominant ABA and GAs in the pistachio concentrates analyzed in this work, respectively. The nut samples had higher values for almost all ABA metabolites and GAs than panicles. The ABA content of the panicles and nuts increased rapidly during flower development (35 DAFB) prior to flower bud abscission while the initial decrease in the ABA content remained constant at a relatively low level at the end of June (intense flower bud abscission), with the minimum levels being obtained during embryo development stage (65 DAFB). However, on day 65 after full flowering, GA₁₉ and GA₄₄ were found to have increased. The plant growth regulator profiles of the pistachio showed delayed spikes in GA and ABA groups indicating that there is a hormone requirement during flower bud abscission and embryo development in pistachio. As a results, GA and ABA metabolites produced in different organs play an important role in the control of pistachios during embryo development and

Keywords: Abscisic acid-metabolites, gibberellins, Pistaciavera L., alternate bearing (flower bud abscission)

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