Abstract
The study investigated the effect of a biohydrogel based on CMC, alginate, and PVA crosslinked with CaCl₂ and citric acid on seed germination and early growth of barley (Hordeum vulgare L.). Seeds were germinated in sand-filled containers containing different hydrogel concentrations: 0, 0.1, 0.25, 0.5, and 0.7%. Germination energy and final germination percentage (GP₃, GP₇), germination index (GI), average germination time (AGT), seedling vigor indices (SVI I, SVI II), as well as shoot and root length were evaluated. It was found that low and medium hydrogel concentrations (0.1–0.5%) stimulated germination and early seedling growth, leading to increased integral indices GI and SVI. The 0.25% concentration provided the highest germination percentage and GI values, while root and shoot development remained balanced and showed no signs of inhibition. The highest hydrogel concentration (0.7%) resulted in a decrease in all vigor parameters, prolonged average germination time, and reduced root and shoot length, indicating limited air and water availability in the substrate at excessive polymer content. The results demonstrate that the CMC/alginate/PVA-based hydrogel is effective in stimulating early barley growth within the optimal concentration range of 0.1–0.5%, whereas exceeding this range may exert inhibitory effects on germination and initial plant development.