Modulatory Effects of Bioregulator on Some Physiological and Nutraceutical Properties of Vigna unguiculata (L.) Walp.

Abstract

Vigna unguiculata (Vu) is one of the most versatile and resilient food legumes among the cultivated crop plants but its growth and development are greatly marred by poor soil fertility, lack of improved seed, pest and diseases, salinity, among others. Bioregulators such as salicylic acid have been shown to participate in various physiological, biochemical and regulatory processes in plants via various mechanisms. Therefore, the present study aimed at examining the modulatory effects of bioregulator (salicylic acid) on some physiological and nutraceutical properties of V. unguiculata.  The V. unguiculata seed cultivars (Ife-BPC and BBT white) were treated with 0.5 and 1.0 µM of Salicylic acid, respectively. They were later sown (number of seeds= 5) in a pot of soil in a randomized completely blocked design. The plants were harvested at maturity and physiological parameters (weights of the fresh leaf, number of leaf, stem girth, percentage germination, number of seeds/pods, and plant height), nutraceutical properties; phytochemicals (qualitative and quantitative) and antioxidants (non-enzyme (ferric reducing antioxidant power, diphenyl picryl hydrazyl, total antioxidant, nitric oxide and hydrogen peroxide and enzyme (superoxide dismutase, peroxidase and catalase) were evaluated. Data were analyzed using descriptive statistics and anova at (P≤0.05). The results showed that physiological parameters, phytochemicals and antioxidants were significantly increased in plant treated with 0.5 and 1.0 µM when compared with control; the highest mean values were observed in plant treated with 1.0 µM of salicylic acid. In addition, Ife-BPC showed higher mean value than BBT-white in all the parameters studied. This therefore implies that salicylic acid at 1.0 µM could serve as an effective concentration to enhance the physiological and nutraceutical value of V. unguiculata.