Natural Phytochemical Extracts Enhance Germination and Early Growth of Barley Hordeum vulgare

Abstract

This study aimed to evaluate the effectiveness of selected local plant extracts as natural growth-promoting alternatives for the germination and seedling growth of Hordeum vulgare within the framework of sustainable agriculture. The treatments included aqueous extracts of leaves of Eriobotrya japonica (Dodonaea), leaves of Psidium guajava, and seeds of Phoenix dactylifera (Asebir date), applied at four concentrations (25%, 50%, 75%, and 100%) in addition to a control treatment. A laboratory germination experiment was conducted for 7 days. Qualitative phytochemical screening was performed, and germination percentage (%), radicle length (cm), and plumule length (cm) were measured. Data were statistically analyzed using ANOVA. The qualitative phytochemical analysis revealed that the Dodonaea extract contained flavonoids (12–15 mg QE/g) and phenolic compounds (10–12 mg GAE/g), in addition to terpenoids. The date seed extract showed high sugar content (18–20% dry weight), flavonoids (5–7 mg QE/g), and phenolic acids (3–5 mg GAE/g). Meanwhile, the guava leaf extract exhibited the presence of tannins (8–10 mg/g), phenolic compounds (6–8 mg GAE/g), and glycosides, indicating clear variation in chemical composition among the studied species. This variation was reflected in the biological response during germination. The Dodonaea extract achieved the highest germination rate (100%) at 25% and 100% concentrations starting from the third day, compared with the control (82%). It also recorded the greatest radicle length (4.5 cm) and plumule length (3.5 cm) on the seventh day at 25–50% concentrations. The date seed extract showed a stimulatory effect at 25–50% concentrations (up to 100% germination), whereas the germination rate decreased to 56% at 100%. In contrast, the guava leaf extract exhibited a clear inhibitory effect, with germination not exceeding 10% at 25–50% concentrations and reaching 33% at 100%, accompanied by a marked reduction in seedling length (<0.3 cm). The results confirm that both the type and concentration of plant extract are critical factors in stimulating or inhibiting germination. Dodonaea extract (25–50%) appears to be a promising natural growth promoter for barley within sustainable agricultural practices.