In recent years, as modern agriculture has placed increasing emphasis on green inputs, efficient resource utilization, and crop quality, plant extracts have gradually become an important area of research in biostimulants. Compared with conventional nutritional products, plant extracts contain a wide range of natural active compounds, including polysaccharides, polyphenols, flavonoids, amino acids, and phytosterols. These compounds can contribute to plant physiological regulation, root development, and responses to environmental stresses.