Biostimulant activity of sulfated polysaccharide extract from red seaweed Halymenia dilatata on yield of Mung bean in greenhouse conditions

The growth-promoting activity of the sulfated polysaccharides isolated from the red alga Halymenia dilatata was evaluated on the yield of mung bean Vigna radiata (L.). The heterogeneous structure of H. dilatata polysaccharide containing α-D- mannuronic acid, (1–6)- d -linked galactons, and sulfate complex was detected by FTIR and 13 C NMR. Mung bean seeds were primed with different concentrations (0–2% w/v ) of sulfated polysaccharide extract and seeds treated with 1.5% polysaccharide showed maximum 90% germination. The seedlings treated with 1.5% of polysaccharide recorded the maximum shoot length (28.52 cm), root length (16.54 cm), leaf area (28.25 mm 2 ), fresh weight (0.93 g), and dry weight (0.49 g) Significantly ( P < 0.05) higher amounts of total chlorophylls, carbohydrate, and protein were detected in the 1.5% polysaccharide-treated plants compared to the control. Furthermore, the number of flowers (15), pod length (7.9 cm), pod weight (0.41 g), and number of seeds (14) per pod were also significantly increased in the 1.5% polysaccharide-treated plants. Hence, our investigation showed that the application of H. dilatata polysaccharide extract could be a potent and eco-friendly biostimulant for improving mung bean growth and yield.