Salt resistance of tomato species grown in sand culture

In this study, Na+, Cl-, K+, Ca2+, chlorophyll and proline levels and the rate of lipid peroxidation level in terms of malondialdehyde (MDA), were investigated in tissues of 15 different tomato cultivars in salt tolerance. As a material, 15 different tomato genotypes were used during a 28-day period and 150 mmol NaCl was applied in sand culture. While one of tomato genotypes was a wild type belonging to Lycopersicum peruvianum, the others were local genotypes belonging to Lycopersicum esculentum L. Better NaCl-stress tolerance in salt-tolerant cultivars as compared to salt-sensitive cultivars observed during the present investigation might be due to restriction of Na+ accumulation and ability to maintain high K+/Na+ ratio in tissue. The chlorophyll level decreased more in salt-sensitive than in salt-resistant cultivars, whereas proline level increased more in salt-sensitive than in salt-resistant cultivars. The exposure to NaCl induced a significant increase in MDA level in both salt-resistant and salt-sensitive cultivars; yet, MDA level was higher in salt-sensitive cultivars. As a result, exclusion or inclusion of Na+, Cl-, K+ and Ca2+ MDA levels, chlorophyll and proline levels may play a key protective role against stress and these features can be used as identifiers for tolerance to salt.