Impact of salicylic acid on antioxidants, biomass and osmotic adjustments in <i>Vigna unguiculata</i> 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