Differential responses of growth, chlorophyll content, lipid peroxidation and accumulation of compatible solutes to salt stress in peanut (<i>Arachis hypogaea</i> L.) cultivars

Abstract

The present study was aimed to compare differential responses of growth, chlorophyll content, lipid peroxidation and accumulation of compatible solutes in peanut (Arachis hypogaea L.) cultivars: Fleur 11 (salt-tolerant), Mbiah and PC 79-79 (moderately-tolerant) and Vanda (salt-sensitive) at the vegetative growth stage, under greenhouse conditions, in the presence of 0, 50, 100 or 200 mM NaCl. The root dry weight (RDW) and shoot dry weight (SDW) of cv. Vanda decreased significantly (p< 0.05) in salt-treated plants than those of cvs. Fleur 11, Mbiah and PC 79-79. The SDW reduction was notably noted at 100 mM NaCl in cvs. Mbiah and PC 79-79, while cv. Fleur 11 showed significantly (P<0.05) decrease in salt-treated plants only at 200 mM NaCl but had higher SDW accumulation than others. The leaf chlorophyll content increased in cvs. Fleur 11 and PC 79-79 and decreased in cv. Vanda with increasing NaCl levels. Proline (PRO) and glycine betaine (GB) contents significantly (p<0.05) increase, for all cultivars, in the stressed plants with the highest quantity in Fleur 11 and the lowest in Vanda. Malondialdehyde levels increased under salt stress in the leaves of cv. Vanda but decreased in cvsMbiah, PC 79-79 and Fleur 11 at 100 and 200 mM, respectively. Total phenolic content increased significantly (p < 0.05) at 200 mM NaCl in the leaves of cv. Vanda than others, while cv. Fleur 11 showed the lowest increase. The salt-tolerant cv. Fleur 11 exhibits a better protection mechanism against oxidative damage caused by salt stress maintaining a higher accumulation of PRO and GB than others. Higher PRO and GB accumulation in the leaves may be regarded as potential biochemical indicator for earlier selection of salt tolerant peanut and targets for improvement through transgenic approaches.

Keywords: Arachis hypogaea, glycine betaine, growth, lipid peroxidation, proline, salt stress

African Journal of Biotechnology, Vol 13(50) 4577-4585