Open Access

ARTICLE

Preliminary Study on Flower Bud Differentiation and Dynamic Changes in Endogenous Hormones in ‘Hongyang’ Kiwifruit

Xiaoqin Zheng¹, Yuqing Wan¹, Qian Zhang², Liqin He², Shihao Tang¹, Qiguo Zhuang², Lihua Wang^2,*

1 Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture and Rural Affairs, Sichuan Province Engineering Technology Research Center of Coarse Cereal Industrialization, College of Food and Biological Engineering, Chengdu University, Chengdu, 610106, China
2 Sichuan Provincial Academy of Natural Resource Sciences, Sichuan Key Laboratory of Kiwifruit Breeding and Utilization, China-New Zealand Belt and Road Joint Laboratory on Kiwifruit, Chengdu, 610015, China

* Corresponding Author: Lihua Wang. Email:

Phyton-International Journal of Experimental Botany 2025, 94(12), 3879-3892. https://doi.org/10.32604/phyton.2025.073229

Received 13 September 2025; Accepted 07 November 2025; Issue published 29 December 2025

Abstract

To investigate endogenous hormone changes in “Hongyang” kiwifruit from overwintering buds to floral morphogenesis (bell-shaped flowering stage), systematic observations were conducted during the undifferentiated stage, axillary bud differentiation stage, and floral morphogenesis stage from late November 2023 to early April 2024. Paraffin sectioning was employed to examine floral bud morphology, while LC-MS targeted metabolomics quantified changes in 15 endogenous hormones across 8 classes. Results indicated floral bud differentiation commenced from late January to early February and concluded by mid-April, spanning approximately 70 days. Approximately 33 days after axillary bud initiation marked the axillary bud primordium differentiation stage, a critical phase for floral differentiation. The period from 33 to 61 days after axillary bud initiation constituted the key stage for female flower differentiation. Indole-3-acetic acid (IAA) levels remained consistently high and stable throughout the process. By the axillary bud primordium differentiation stage, abscisic acid (ABA), salicylic acid (SA), tylosterol (TY), and trans-zeatin riboside (tZR) levels significantly decrease, while 1-aminocyclopropane carboxylic acid (ACC), gibberellic acid (GA4), isopentenyladenine riboside (iPR), 12-oxo-phytodienoic acid (12-OPDA), cis-zeatin (cZ), trans-zeatin (tZ), and cis-zeatin riboside (cZR) significantly increased. The study speculates that higher IAA levels may promote female flower differentiation; lower ABA levels favor floral bud differentiation; lower jasmonic acid (JA) levels may be associated with stamen abortion; lower SA levels favor female flower differentiation and development; and higher ACC and GA4 levels may promote female flower differentiation and flowering and subsequent development, respectively.

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Keywords

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