Effects of salt stress on physiological and postharvest quality characteristics of different Iranian genotypes of basil

This study examined the effects of salt stress on the physiological responses and postharvest quality characteristics of fresh sweet basil (Ocimum basilicum L.). Plants were treated with 40 and 80 mM NaCl for 25 days during cultivation in 2014. Two green genotypes, Green Iranian and Genovese basil, were studied after harvest, and while two Iranian genotypes, Green and Purple Iranian basil, were compared during storage. Yield and the stem length were significantly reduced under salt stress only in the two Iranian cultivars. Salinity significantly reduced leaf thickness and the area of parenchyma cells in both Green Iranian and Genovese basil. As salt concentration increased, transpiration and the content of chlorophylls decreased significantly while the lipid peroxidation increased in the Genovese genotype. During storage at 12°C, the respiration rate of salt-stressed leaves was similar to that of control leaves. The visual quality of Purple Iranian basil was better preserved during storage than the Green Iranian basil. However, salt stress positively affected the visual quality of Green Iranian basil, decreasing darkening and maintaining the quality above the limit of marketability after 7 days of storage. The total content of phenolic acids and anthocyanins did not show significant differences between growth conditions. However, during storage of Green Iranian basil, salt stress increased the content of individual and total phenolic acids compared to the control. To summarize, the positive or negative effects of salt stress on basil depend on the degree of tolerance of the different genotypes.