Effect of Salt Stress on Some Physio-Biochemical Traits and Antioxidative Enzymes of Two Brassica Species Under Callus Culture

Abstract The changes in lipid peroxidation, H2O2, proline, protein and the involvement of the different antioxidant system (catalase, gayacoule peroxidase, ascorbate peroxidase) and callus-related traits were investigated in relation to salt stress in the callus of two different ploidy levels of Brassica including B. juncea and B. oleracea. The calluses of B. juncea genotypes were less sensitive to NaCl stress than that of B. oleraceae by increasing concentrations of NaCl from 0 to 200 mM.Tetraploid genotype (B. juncea cr3356) showed significant increase in the contents of protein and proline, and also activity of giacle peroxidase and catalase enzymes at higher salinity levels. Also, a significant decrease in the amount of H2O2 and malondialdehyde occurred with increasing the salinity intensity. Diploid cultivar (B. oleracea bra 2828) had the lowest enzymatic activities and the highest content of H2O2 and malondialdehyde with an increase in the salinity level. Therefore, this genotype was identified as the most sensitive cultivar to the salinity stress. The difference in the salinity resistance between diploid and amphidiploid species may be due to differences in the ploidy level of these species. This result suggests that tetraploid genome of B. oleraceae could be considered as a suitable candidate for production under salinity conditions by maintaining higher activities of antioxidant enzymes.