Priming with Methylene Blue Enhances the Antioxidant Properties and Germination Power of Cowpea, Millet and Sorghum Seeds

Seed priming is the preparation of plants to overcome stress with the aim of improving the efficiency and rate of germination. The effect of priming cowpea, millet and sorghum seeds with methylene blue (MB) on germination power (GP) was investigated in this work. The seeds were primed by steeping for 6 h in different concentrations of MB solution, germinated over 48 h on wet cotton and the GP determined. Further, soluble protein and total phenolic contents, and the antioxidant properties [scavenging ability for hydrogen peroxide, nitric oxide, hydroxyl radical and 2,2-diphenyl-1-picrylhydrazyl (DPPH) and iron chelation ability] of the seeds steeped in MB that gave the highest GP were determined. The highest GP was observed for cowpea and sorghum seeds steeped in 80 µM MB solution and 60 µM MB solution for millet seeds. At these MB concentrations, a faster rate of germination coupled with an increase in soluble protein and total phenolic content was observed. The increase in germination rate was also characterized by enhanced antioxidant properties of the seeds. The results of this study show that priming with MB can be used to improve the germination of these seeds.