Impact of salicylic acid on antioxidants, biomass and osmotic adjustments in Vigna unguiculata L. walp. during water deficit stress

Abstract

Ameliorative impact of salicylic acid (SA) on Vigna unguiculata L. (cowpea) cultivar IT93k-452-1 during water deficit stress was investigated. Plants were subjected to water deficit stress (WD) for 7 days at either the vegetative stage (DVS) or the reproductive stage (DRS) and the leaf water potentials (ψw) of - 1.9 MPa and -2.01 MPa were obtained, respectively. Stress caused reductions in almost all parameters studied. 3 and 5 mM SA foliar treatment caused increases of 27% in leaf ψ_w, 94% in chlorophyll content, 75% in plant biomass, 7% in nitrate reductase activity and 38% in proline content in DVS plants while the impact was much lower in DRS plants. Stress stimulated almost 3-fold increase in antioxidant vitamin B12 in DVS plants and 40% increase in vitamin C in DRS plants and SA (3 mM) further increased the latter by 14%. Overall, SA had a protective influence on the water potential and growth of stressed plants accompanied by an increase in production of osmolyte proline and antioxidant vitamin C.

Keywords: Antioxidants, growth, salicylic acid, water stress.

African Journal of BiotechnologyVol. 12(33), pp. 5200-5207