title: Dormancy release and flowering time in Ziziphus jujuba Mill., a "direct flowering" fruit tree, has a facultative requirement for chilling.
abstract: In deciduous fruit trees, the effect of chilling on flowering has mostly been investigated in the "indirect flowering" group, characterized by a period of rest between flower bud formation and blooming. In the present study, we explored the effects of chilling and chilling deprivation on the flowering of Ziziphus jujuba, a temperate deciduous fruit tree belonging to the "direct flowering" group, in which flower bud differentiation, blooming and fruit development occur after dormancy release, during a single growing season. Dormancy release, vegetative growth and flowering time in Z. jujuba cv. Ben-Li were assessed following several treatments of chilling. Chilling treatments quantitatively decreased the timing of vegetative bud dormancy release, thereby accelerating flowering, but had no effect on the time from dormancy release to flowering. Trees grown at a constant temperature of 25°C, without chilling, broke dormancy and flowered, indicating the facultative character of chilling in this species. We measured the expression of Z. jujuba LFY and AP1 homologues (ZjLFY and ZjAP1). Chilling decreased ZjLFY expression in dormant vegetative buds but had no effect on ZjAP1expression, which reached peak expression before dormancy release and at anthesis. In conclusion, chilling is not obligatory for dormancy release of Z. jujuba cv. Ben-Li vegetative buds. However, the exposure to chilling during dormancy does accelerate vegetative bud dormancy release and flowering.
authors.affiliation: French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel.
authors.forename: Michal
authors.initials: M
authors.lastname: Meir
authors.affiliation: French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Ransbotyn
authors.affiliation: Citriculture, Gilat Research Center, Agricultural Research Center, Israel.
authors.forename: Eran
authors.initials: E
authors.lastname: Raveh
authors.affiliation: French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel.
authors.forename: Simon
authors.initials: S
authors.lastname: Barak
authors.affiliation: French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel. Electronic address: telzur@bgu.ac.il.
authors.forename: Noemi
authors.initials: N
authors.lastname: Tel-Zur
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel. Electronic address: mzaccai@bgu.ac.il.
authors.forename: Michele
authors.initials: M
authors.lastname: Zaccai
mesh_terms: D035264:Flowers / Q000254:growth & development* / Q000502:physiology; D005638:Fruit / Q000254:growth & development / Q000502:physiology; D057445:Plant Dormancy / Q000502:physiology*; D012098:Reproduction; D012621:Seasons; D014197:Trees; D031957:Ziziphus / Q000254:growth & development* / Q000502:physiology
keywords: Dormancy release; Flowering; Rhamnaceae; Ziziphus jujuba; ZjAP1; ZjLFY