JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2024, Vol. 48 ›› Issue (5): 97-104.doi: 10.12302/j.issn.1000-2006.202301007

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Induction and physiological regulatory mechanism of secondary flowering in Yulannia denudata

CHEN Xiangbo1(), ZHANG Dongmei1,*(), FU Renjie1, ZHANG Lang1, SHEN Yamei2, LUO Yulan1, YIN Lijuan1   

  1. 1. Shanghai Academy of Landscape Architecture Science and Planning, Shanghai Engineering Research Center of Landscaping on Challenging Urban Sites, Shanghai 200232, China
    2. School of Landscape Architecture, Zhejiang Agriculture and Forestry University, Hangzhou 311302, China
  • Received:2023-01-06 Revised:2023-03-15 Online:2024-09-30 Published:2024-10-03
  • Contact: ZHANG Dongmei E-mail:cxb7210@163.com;zdm@shsyky.com

Abstract:

【Objective】The aim of this study was to achieve the secondary flowering of Yulannia denudata through artificial induction and to explore the physiological regulation mechanism of flower bud differentiation and flowering induction in Y. denudata.【Method】Y. denudata plants were treated with nutrients and hormones. Flower buds were embedded in paraffin and sectioned to observe flower bud development, and endogenous hormone contents in flower buds at different stages were measured.【Result】Flower bud differentiation of Y. denudata began in early May when vegetative growth slowed down and was completed by early June. Secondary flowering within the same year was induced via treatment with exogenous hormones [6-benzylaminopurine (6-BA) and gibberellin A3 (GA3)] alone or in combination with nutrient applications [nitrogen (N), phosphorus (P), potassium (K) and sugars]. The secondary flowering rate ranged from 33% to 100%, with the maximum of 22 flowers per plant. During the maturation of flower bud differentiation, the levels of endogenous GA3 and abscisic acid (ABA) increased. The ABA content in flower buds decreased while breaking dormancy and flowering, whereas the content of endogenous auxins (indole-3-acetic acid (IAA) and methylindole-3-acetic acid (ME-IAA) increased. Flower buds treated with exogenous cytokinins had higher levels of ME-IAA, IPA, jasmonoyl-l-isoleucine (JA-Ile) and jasmonate (JA), while flower buds treated with exogenous gibberellins (GA3) had higher levels of endogenous trans-zeatin riboside (tZR), gibberellin A1 (GA1), and GA3. 【Conclusion】Exogenous hormones directly induce secondary flowering in Y. denudata without relying on nutrient treatments. Thus, different hormones may induce secondary flowering through various regulatory pathways.

Key words: Yulannia denudata, differentiation of flower bud, secondary flowering, physiological regulation, nutrition, hormone

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