Effects of Caffeine on the Seed Germination of Bambara Groundnut ( Vigna subterranean (L.) Verdc)

Abstract

This study was conducted to determine the effects of different caffeine concentrations on seed germination of Bambara groundnut. The seeds were pre-soaked in distilled water for 12 hours and then exposed to the different concentrations of the caffeine doses prepared on weight basis, i.e. 0.005 %, 0.25 %, 0.5 %, and 0.75 % 1.0 %, 1.25 %, 1.5%, 1.75% and 2.0% w/w caffeine in solution, prepared in a phosphate buffer of pH-7 2. Three replications of the treatments were made and sown with each seed of the treated concentrations in a pot using a Complete Randomized Block Design (CRBD). Seed germination was scored for seven days and the germinated seedlings were further observed for 9 weeks. The radicle length, shoot height, and stem girth were measured weekly after germination. From the results, it was evident that increased concentration of caffeine reduced the germination percentage of the seeds. The caffeine concentrations of 1.75-2.0% recorded no germination compared with more than 90% germination at the end of the 7 days recorded in the case of 0.05-0.25% caffeine concentrations. There was a reduction in radicle length as the caffeine concentration increased at 7 weeks after planting. 0.5% caffeine concentration recorded the highest shoot length of 3.32cm among the caffeine concentrations with no significant difference detected in the stem girth studied. From the results obtained therefore, lower caffeine concentrations showed an increase in Bambara groundnut germination, hence could result in general improvement in crop yield.