Mechanisms of plant extracts in alleviating drought and saline-alkali stress in plants

Drought and saline-alkali stress significantly inhibit plant growth. Exogenous plant extracts, an effective approach to mitigate abiotic stresses, have drawn extensive attention. However, a systematic summary of their mechanisms remains incomplete. This review summarizes recent advances in the role of plant extracts in enhancing drought and salt tolerance, including extraction methods such as solvent extraction, ultrasound-assisted extraction, and microwave-assisted extraction, as well as application methods like foliar spraying, seed treatment, and soil application. Researches indicate that plant extracts improve stress resistance through synergistic mechanisms: 1) accumulation of osmotic adjustment substances to maintain cellular osmotic balance; 2) enhancement of antioxidant enzyme activity to reduce reactive oxygen species accumulation and membrane lipid peroxidation; 3) regulation of selective ion uptake to maintain Na⁺/K⁺ homeostasis; 4) modulation of hormone signaling pathways to optimize stomatal behavior and root development; 5) protection of photosynthetic systems to stabilize chlorophyll content and photochemical efficiency; and 6) improvement of nutrient absorption and metabolic allocation. Despite these benefits, challenges such as unstable active components and high costs persist. Future research should integrate multi-omics technologies to elucidate molecular mechanisms, optimize extraction processes, and explore synergistic effects with exogenous substances like calcium signaling to promote large-scale applications in sustainable agriculture. • Summarizes plant extracts’ extraction methods & application approaches. • Plant extracts enhance plant drought and salt tolerance via multiple mechanisms. • Proposes plant extracts’ challenges & multi-omics integration for applications.