TY  - EJOU
AU  - Voytenko, Lesya 
AU  - Shcherbatiuk, Mykola 
AU  - Vasyuk, Valentyna 
AU  - Romanenko, Kateryna 
AU  - Babenko, Lidiya 
AU  - Smirnov, Oleksandr 
AU  - Kosakivska, Iryna 

TI  - Adaptive Responses of Secale Cereale to Moderate Soil Drought: Role of Phytohormones, Free Amino Acids, and Phenolic Compounds
T2  - Phyton-International Journal of Experimental Botany

PY  - 2025
VL  - 94
IS  - 7
SN  - 1851-5657

AB  - 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 (<i>Secale cereale</i> 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 (GA<sub>3</sub> + GA<sub>4</sub>) significantly decreased in roots. GA<sub>3</sub> 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 GA<sub>4</sub> accumulation in roots led to a rise in total gibberellin levels. In contrast, shoot GA<sub>3</sub> + GA<sub>4</sub> levels declined, primarily due to GA<sub>3</sub> 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.
KW  - <i>Secale cereale</i> L.; soil drought; growth; phytohormones; amino acids; phenols; flavonoids; adaptation strategies

DO  - 10.32604/phyton.2025.067772