Effect of humic acid on some morphological and physiological characteristics of strawberry (Fragaria × ananassa Duch. cv. Sabrina) under salinity stress

Salinity is a signifigant environmental factor limiting productivity of agricultural crops. In order to determine the effect of humic acid on some morphological and physiological characteristics of strawberry (Fragaria × ananassa Duch. cv. Sabrina) under salinity stress, a greenhouse experiment was conducted with three factors including two treatment methods (spray and drench), three humic acid levels (0, 300 and 600 mg l-1) and three of salinity levels (0, 20 and 40 mM) in a completely randomized design with four replications. The results indicated that with increase in salinity levels of nutrient solution,the plant root length, leaf area, leaf fresh and dry weight, chlorophylls a, b comems and total chlorophyll were reduced. Under salt stress, the electrolyte leakage of leaf cell and amount of malondialdehyde were increased. Under salt stress conditions, addition of humic acid enhanced growth characteristics, but reduced electrolyte leakage. In conclution, application of humic acid (especially at 600 mg l-1) ameliorated the deleterious effects of salt stress in strawberry cv. Sabrina.