Effects of salinity stress on seedlings growth, mineral nutrients and total chlorophyll of some tomato (Lycopersicum esculentum L.) cultivars

Abstract

In this study, six cultivars of tomato (Lycopersicum esculentum L. var. Jaguar, Xewel, Nadira, Lindo, Mongal and Ninja) were evaluated. They were subjected to salt stress during vegetative growth. Three concentrations of salt solution 50, 100 and 200 mM NaCl and the control (Wacquant nutrient solution) were used in irrigation. The total chlorophyll, the dry weight of seedlings (roots dry weight, stems dry weight and leaf dry weight), the plant height and the mineral nutrient concentrations (Na⁺, K⁺ and Ca²⁺) were determined. The results showed that the salt treatments increased significantly Na⁺ concentrations in roots, stems and leaves of plants, whereas K⁺ and Ca²⁺ concentrations and K⁺/Na⁺ selectivity ratio of plants were decreased in all tomato cultivars. The results also revealed after six weeks of salt treatments that the dry weight partitioning and the plant height decreased significantly in Jaguar, Xewel, Nadira and Mongal with increasing salinity. Jaguar, Xewel, Nadira and Mongal can therefore be considered as salt-sensitive cultivars which tolerance level ranges from 0 to 50 mM NaCl. The Lindo and Ninja plant height was less affected by salt stress than the four other cultivars. In Ninja, the moderately salt-tolerant cultivar, the growth parameters were significantly reduced at 100 mM NaCl. The supply of mineral nutrient solution with NaCl did not affect significantly leaf total chlorophyll content and plant organs dry weight of Lindo at 100 mM NaCl suggesting that it was relatively more tolerant in saline medium than other cultivars studied. The Lindo cultivar could be cultivated in environments with relatively moderate salinity.

Keywords: Growth, Lycopersicum esculentum, tolerance, mineral nutrients, plant organs

African Journal of Biotechnology Vol. 9(33), pp. 5366-5372, 16 August, 2010