Abstract

Salt stress is a major challenge in agricultural system. In this study, okra seeds of two genotypes (47-7 and LD 88) were presoaked with 10-2, 10-4, and 10-6 mM salicylic acid and control in distilled water, then the soil was treated with 0, 50, 100, 150 and 200 mM NaCl. The experiment was conducted to study the effect on osmoregulating solutes such as proline, salt stress protein (glycine betaine and proline betaine) and soluble sugars (glucose and fructose). Results showed that proline content increased with increased in the concentrations of salinity. Also, treatment with salicylic acid (SA) improved salt stress proteins accumulation in both stressed genotypes. In contrast, decreased SA concentrations improved soluble sugar accumulation in the fruit of okra genotype 47-4. But in LD88, increased in the level of SA resulted to the increased soluble sugar accumulation in the leaf. Combined effect of SA and salinity caused a greater accumulation of protein and soluble sugar in leaf and fruit of both genotypes of stressed okra, but significant increased were seen only in the groups of LD88 treated with 10-4 mM SA at 50 mM NaCl in leaf and 10-2mM SA at 150 mM NaCl in fruit when compared with the control group. Salinity induced a marked decreased in reducing sugar accumulation of okra plant (LD88), especially at high salinity level (200 mM NaCl). Therefore, accumulations of compatible solutes such as salt stress proteins may provide plant a storage form of nitrogen that will be re-utilized later and may play a role in osmotic adjustment.

Key words: Distilled water, fruit, leaf, okra, proline, protein, salicylic acid (SA), salinity, soluble sugar.