Open Access

ARTICLE

Adaptive Responses of Secale Cereale to Moderate Soil Drought: Role of Phytohormones, Free Amino Acids, and Phenolic Compounds

Lesya Voytenko^1,*, Mykola Shcherbatiuk¹, Valentyna Vasyuk¹, Kateryna Romanenko¹, Lidiya Babenko¹, Oleksandr Smirnov^2,3, Iryna Kosakivska¹

1 Department of Phytohormonology, M.G. Kholodny Institute of Botany National Academy of Sciences of Ukraine, Kyiv, 01004, Ukraine
2 Educational and Scientific Center “Institute of Biology and Medicine” of Taras Shevchenko Kyiv National University, Kyiv, 03127, Ukraine
3 Institute of Plant Physiology and Genetics, National Academy of Sciences of Ukraine, Kyiv, 02000, Ukraine

* Corresponding Author: Lesya Voytenko. Email:

(This article belongs to the Special Issue: Stress Metabolites of Plants: Protective and Regulatory Functions)

Phyton-International Journal of Experimental Botany 2025, 94(7), 2195-2214. https://doi.org/10.32604/phyton.2025.067772

Received 12 May 2025; Accepted 07 July 2025; Issue published 31 July 2025

Abstract

Prolonged lack of rain and high-temperature lead to soil water deficits, inhibiting cereal crop growth in early ontogenesis and reducing grain quality and yield. Rye (Secale cereale L.) is a key grain crop, particularly in regions where wheat cultivation is challenging or unfeasible. To clarify its drought adaptation mechanisms, we analyzed the effects of moderate soil drought on growth, hormonal homeostasis, and the dynamics and distribution of free amino acids and phenolic compounds in rye at early vegetative stages and post-recovery. Drought triggered both general and organ-specific changes in endogenous phytohormones. A nonspecific response involved the accumulation of stress hormones abscisic acid (ABA) and salicylic acid (SA), alongside the suppression of growth hormones indole-3-acetic acid (IAA) and gibberellins. However, hormone dynamics and localization varied across plant organs. ABA and SA levels significantly increased in shoots of drought-stressed and recovered plants, corresponding with inhibited growth. Prolonged drought further enhanced ABA accumulation in both shoots and roots of recovered plants, while SA levels declined in roots but remained elevated in shoots. Drought also caused a substantial reduction in IAA, particularly in shoots, while gibberellins (GA₃ + GA₄) significantly decreased in roots. GA₃ was predominant in most samples, except in the shoots of 2-day-old control plants. Post-recovery, IAA levels increased but remained below control values, while GA₄ accumulation in roots led to a rise in total gibberellin levels. In contrast, shoot GA₃ + GA₄ levels declined, primarily due to GA₃ reduction. The dominant free amino acids: aspartic acid, glutamic acid, glycine, alanine, and leucinedecreased significantly, underscoring their key role in stress adaptation. Increased flavonoid accumulation, especially in roots, suggests their involvement in antioxidant defense against oxidative stress. A significant increase in ABA and SA levels, along with a marked reduction in IAA and GA content in stressed rye plants occurred alongside a reduction in free amino acid content, accumulation of phenolic compounds, and an increase in flavonoid levels. These findings indicate distinct adaptation strategies in rye shoots and roots under moderate soil drought. They provide a foundation for further research on drought resistance mechanisms in cereals and the development of strategies to enhance their adaptive potential.

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