Influence of NaCl Salinity on Vegetative Growth, Nutrient Uptake and Proline Content in Two Tomato Cultivars Grown Under Greenhouse Conditions

Effect of four NaCl salinity levels; 2.0 (control), 6.0, 8.3 and 15.0 dS m-1 on the performance of two tomato commercial F1 tomato hybrids, “Maha” (normal fruited) and Pepe (Cherry type), were investigated in pot experiments under greenhouse conditions to evaluate the relative degree of salt tolerance at the seedling stage. In general, application of 8.3 and 15.0 dS m-1 at the cotyledon stage, significantly reduced seedling shoot and root fresh and dry weights, increased Na, Cl and proline accumulation and significantly reduced accumulation of K, Mg and Ca. However, under low salinity levels (2.0 to 6.0 dS m-1) both cultivars were able to stand certain amounts of Na and Cl in their shoots without significant reductions in weight. Under high salinity levels (8.3 and 15.0 dS m-1), reductions in shoot fresh weights and leaf area in response to salinity were higher than the other vegetative growth parameters in both cultivars and to a greater extent in “Maha”. “Maha” accumulated less Na and Cl in shoots, while “Pepe”, accumulated higher Na and Cl. The reduction in vegetative growth parameters was associated with the increase in Na and Cl accumulation. Linear regression between ion regression index and relative shoot and root dry weights showed that the inhibitory effect of Cl was greater than Na on vegetative growth and to a higher extent in “Maha”. Abbreviations: Days After Salt Treatment: DAST, Ion Regression Index (IRI).