title: GA4 and IAA were involved in the morphogenesis and development of flowers in Agapanthus praecox ssp. orientalis.
abstract: The transition from vegetative to reproductive growth represents a major phase change in angiosperms. Hormones play important roles in this process. In this study, gibberellic acid (GA), cytokinins (CKs), indoleacetic acid (IAA), and abscisic acid (ABA) were analyzed during the flowering in Agapanthus praecox ssp. orientalis. Eleven types of endogenous gibberellins in addition to GA1 were detected in various organs. GA9 was detected with the highest concentrations, followed by GA5, GA8, and GA19. However, GA4 was the main bioactive GA that was involved in the regulation of flowering. Eight types of endogenous cytokinins were detected in A. praecox ssp. orientalis, and zeatin, zeatin riboside, zeatin-O-glucoside, and N(6)-isopentenyladenosine-5-monophosphate were present at higher levels throughout the study, of which zeatin plays an important role in the development of various organs. IAA increased by 581% in the shoot tips from the vegetative to inflorescence bud stages and had the most significant changes during flowering. Phytohormone immunolocalization analysis suggested that IAA involved in differentiation and development of each floral organs, GA and zeatin play important roles in floret primordia differentiation and ovule development. Using exogenous plant growth regulators proved that GA signaling regulate the scape elongation and stimulate early-flowering, and IAA signaling is involved in the pedicel and corolla elongation and delay flowering slightly.
authors.affiliation: Department of Landscape Science and Engineering, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Di
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Landscape Science and Engineering, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Li
authors.initials: L
authors.lastname: Ren
authors.affiliation: Department of Landscape Science and Engineering, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Jian-hua
authors.initials: JH
authors.lastname: Yue
authors.affiliation: Department of Ornamental Plants and Horticulture, College of Landscape Architecture, Northeast Forestry University, Harbin 150040, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Ornamental Plants and Horticulture, College of Landscape Architecture, Northeast Forestry University, Harbin 150040, China.
authors.forename: Li-huan
authors.initials: LH
authors.lastname: Zhuo
authors.affiliation: Department of Landscape Science and Engineering, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address: shenxh62@sjtu.edu.cn.
authors.forename: Xiao-hui
authors.initials: XH
authors.lastname: Shen
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D003583:Cytokinins / Q000378:metabolism; D035264:Flowers / Q000254:growth & development / Q000378:metabolism*; D005875:Gibberellins / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism*; D019684:Magnoliopsida / Q000254:growth & development / Q000378:metabolism*
chemical_list: D003583:Cytokinins; D005875:Gibberellins; D007210:Indoleacetic Acids; C030737:indoleacetic acid; D000040:Abscisic Acid; C007842:gibberellic acid
keywords: ABA; Agapanthus praecox ssp. orientalis; Cytokinin; Flowering; Gibberellin