Growth, Lipid Peroxidation and Antioxidant Enzyme Activities as a Selection Criterion for the Salt Tolerance of Wheat Cultivars Irrigated by Seawater

Growth and oxidative stress were used as markers to differentially characterize salt-tolerant wheat plants. Different responses of two wheat (Triticum aestivum L.) cultivars (Gemmieza-9 and Sids-1) subjected to seawater at a percentage of 10% or 25 % were investigated. In general, seawater at 10% and 25% caused noticeable reduction in root/shoot ratio, root density, root distribution, flag leaf area and specific leaf area as well as in the degree of succulence and sclerophylly during grain filling. Furthermore, reduction was more pronounced at the higher salinity level as compared to the lower one, particularly in Gemmieza-9. Seawater increased the malondialdehyde content in both wheat cultivars as compared to control plants, the increase being significantly higher in Gemmieza-9 than in Sids-1. The lower level of lipid peroxidation in Sids-1 probably indicated better protection against oxidative damage caused by seawater. Concomitant, the two applied concentrations of seawater reduced membranes stability resulting in an increased membrane leakage. Gemmieza-9 was characterized by the highest degree in membrane leakage and the lowest value of the membrane stability index. The activity of the antioxidant enzymes catalase, peroxidase and ascorbic acid oxidase increased under seawater irrigation in both cultivars with a higher increase in Sids-1 than in Gemmieza-9. Therefore, the presented results indicated that Sids-1 (resistant cultivar) had a higher potential to withstand seawater stress than Gemmieza-9 (sensitive cultivar).