Utilization of seaweed Sargassum myriocystum extracts as a stimulant of seedlings of Vigna mungo (L.) Hepper

The effect of seaweed liquid fertilizer (SLF) of Sargassum myriocystum on germination, growth and biochemical constituents of Vigna mungo was studied. Different concentrations (5%, 10%, 25%, 50% and 75%) of SLF were prepared using distilled water. A total of 100 seeds were soaked for each SLF concentration for a 24-h period and were later placed in various Petri plates and watered regularly. Water-soaked seeds were used as controls. Seed germination was 98% for the 10% SLF soaked seeds. Similarly, shoot length (21.13 cm seedling–1), root length (12.19 cm seedling–1), fresh weight and dry weight (3.910 and 0.320 g seedling–1) recorded at 10% concentration of S. myriocystum treated seedlings were the highest. Besides, the chlorophyll (0.547 mg g–1 fr. wt.) and carotenoid (0.359 mg g–1 fr. wt.) contents in leaves recorded at 10% SLF soaked seedlings were the highest. The 10% SLF treated seedlings showed the highest content of protein (1.898 and 1.508 mg g–1 fr. wt.), amino acid (0.370 and 0.306 mg g–1 fr. wt.), reducing sugar (6.031 and 3.448 mg g–1 fr. wt.), total sugar (8.414 and 7.055 mg g–1 fr. wt.), α-amylase activity (1.403 and 1.380 μg min–1 mg–1 protein) and β-amylase activity (1.099 and 1.029 μg min–1 mg–1 protein) of shoots and roots respectively. The seaweed extract showed better response at lower concentration while higher concentrations of seaweed extract showed a decreasing trend. Additional key words: biofertilizer; black gram; seaweed liquid fertilizer.