Development And Evaluation of a Sargassum-based Biostimulant Formulation for Improving Maize Seedling Vigour

Abstract

Aims: To develop an acid-hydrolysed Sargassum-based biostimulant formulation and evaluate its biochemical characteristics and effectiveness in improving seed germination and early seedling growth of maize. Study Design: A laboratory seed germination experiment was conducted using a Completely Randomised Design (CRD), with four treatments and three replicates. Place and Duration of Study: The study was conducted at the Department of Soil Science and Agricultural Chemistry, Anbil Dharmalingam Agricultural College and Research Institute, Tamil Nadu Agricultural University, Tiruchirappalli, Tamil Nadu, India, from April to July 2026. Methodology: Sargassum biomass collected from Mandapam, Rameswaram, Tamil Nadu, was washed, shade-dried, powdered, and subjected to partial acid hydrolysis using 5% (v/v) nitric acid at a 1:10 solid-to-liquid ratio for 24 h at 30°C. The hydrolysed extract was characterised for phenolics, tannins, flavonoids, terpenoids, and phytosterols. Fourier-transform infrared spectroscopy (FTIR) and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) were used to characterise the hydrolysed extract. Maize CO(H)M8 hybrid seeds were treated with 1, 2, and 3% acid-hydrolysed Sargassum formulation and evaluated using the roll-towel method for germination and seedling growth. Results: The acid-hydrolysed extract contained phenolics (5.92 ± 0.14 mg GAE mL⁻¹), tannins (4.15 ± 0.11 mg TAE mL⁻¹), flavonoids (3.84 ± 0.09 mg QE mL⁻¹), terpenoids (2.71 ± 0.07 mg LE mL⁻¹), and phytosterols (2.24 ± 0.05 mg CE mL⁻¹). FTIR analysis showed characteristic absorption bands at 3344, 1631, 1324, and 1041 cm⁻¹, indicating changes in functional groups following acid treatment. MALDI-TOF MS showed major peaks at m/z 2053, 4664, 7569, 9322, 11934, 13736, and 18475. The Sargassum-based treatments improved maize seed germination and seedling growth compared with the untreated control. The 3% formulation recorded the highest germination (95.2%), root length (12.6 cm), shoot length (13.4 cm), stem girth (3.8 mm), fresh weight (1.42 g seedling⁻¹), and dry weight (0.33 g seedling⁻¹). Conclusion: The acid-hydrolysed Sargassum-based formulation enhanced maize seed germination and early seedling growth, with the 3% formulation showing the best overall performance. The developed formulation has potential as a sustainable seaweed-based biostimulant for improving maize seedling establishment.