Salt resistance of tomato species grown in sand culture

Abstract

In this study, Na<sup>+</sup>, Cl<sup>–</sup>, K<sup>+</sup>, Ca<sup>2+</sup>, 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<sup>+</sup> accumulation and ability to maintain high K<sup>+</sup>/Na<sup>+</sup> 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<sup>+</sup>, Cl<sup>–</sup>, K<sup>+</sup> and Ca<sup>2+</sup> 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.