Open Access

ARTICLE

The Role of Prohexadione-Calcium in Mediating the Alleviation of Shading Stress in Hesperis sibirica

Xiaoyu Che^1,2,#, Yanlong Wang^1,2,#, Junling Wang^1,2, Linru Liang^1,2, Yuxin Li^1,2, Guoku Liu^3,*, Yanhui Li^1,2,4,5,*, Ping Li^1,2,5,*

1 College of Landscape and Tourism, Hebei Agricultural University, Baoding, China
2 College of Forestry, Hebei Agricultural University, Baoding, China
3 College of Agronomy, Hebei Agricultural University, Baoding, China
4 National Engineering and Technology Center for Northern Mountain Agriculture, Baoding, China
5 Hebei Key Laboratory of Floral Biological Breeding, Baoding, China

* Corresponding Authors: Guoku Liu. Email: ; Yanhui Li. Email: ; Ping Li. Email:
# These authors contributed equally to this work

(This article belongs to the Special Issue: Abiotic and Biotic Herb Stress: Mechanisms, Physiology and Biochemical Changes)

Phyton-International Journal of Experimental Botany 2026, 95(8), 9 https://doi.org/10.32604/phyton.2026.086214

Received 26 May 2026; Accepted 14 July 2026; Issue published 28 August 2026

Abstract

Shading stress significantly compromises the ornamental quality and ecological adaptability of Hesperis sibirica. To investigate the potential mitigating effects of plant growth regulators, this study systematically analyzed the regulatory mechanisms of foliar-applied prohexadione-calcium (Pro-Ca) at different concentrations (0, 100, 300, 600, and 900 mg·L⁻¹) under both full sunlight and heavy shading (70% light reduction, retaining 30% of full sunlight intensity) conditions. Through comprehensive evaluation of plant morphological traits, chlorophyll content, photosynthetic parameters, and chlorophyll fluorescence characteristics, combined with structural observations using scanning electron microscopy, light microscopy, and transmission electron microscopy, 600 mg·L⁻¹ Pro-Ca was identified as the optimal concentration for alleviating shading stress. This treatment significantly reduced plant height compared to the shading control, while also increasing floret number (50 d). During the observation period, the chlorophyll a/b ratio showed a notable improvement, accompanied by significant enhancements in the net photosynthetic rate (P_n) and maximum photochemical efficiency (F_v/F_m). Structural analysis revealed that this concentration promoted leaf thickening, stomatal optimization, and chloroplast ultrastructure repair. The comprehensive evaluation results confirmed that 600 mg·L⁻¹ Pro-Ca provided the comparatively comprehensive regulatory effect under shading conditions.

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Keywords

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