Germination and initial grown of Vigna unguiculata (L.) Walp.under salt stress

Abstract

Salt stress condition during seed germination affects seedling emergence in the field, and hence, the stand of plants and crop growth. Therefore, the objective of this study was to evaluate the effects of salt stress induced by NaCl and CaCl₂ solutions, and the combination of CaCl₂ + NaCl on germination and early growth of cowpea seedlings, cultivar BR 17 Gurguéia. The experiment was conducted in a completely randomized design in a factorial arrangement of 3 x 6, with four repetitions, being the first factor the different salts, and the second the salinity levels: 0.0, 2.5, 5.0, 7.5, 10.0 and 12.5 dS m^-1. First count, germination speed index, abnormal seedlings, seedlings length, and dry mass were evaluated the germination. Salinity levels between 2.5 and 5.0 dS m^-1 favor germination and early seedling growth; however, at higher salt concentrations the performance of cowpea seeds is adversely affected, regardless of the used salt. The induction by CaCl₂ provides more severe effects on seedling growth in comparison with NaCl, whereas the combination of CaCl₂ + NaCl attenuates salt stress, yielding more vigorous seedlings.