Responses of the Tomato (Lycopersicon esculentum Mill.) Plant to Exposure to Different Salt Forms and Rates

We aimed to investigate the effects of NaCl and Na2SO4 on seed and pollen germination of tomato (Lycopersiconesculentum Mill.) in vitro. In addition, the effects of NaCl, Na2SO4, and CaCl2 on yield and quality, plant growth, some physiologicalparameters, and the distribution of mineral composition in greenhouse grown tomato plants were investigated. Seed germinationwas affected by high salinity treatments (MS and 1/2 MS). Pollen germination and pollen tube length were significantly affected bysalt forms and doses. Pollen germination was blocked by the above doses of 50 mM NaCl and 30 mM Na2SO4. In the greenhouseexperiment, with increasing concentration of all forms of salt, stomatal density, chlorophyll content, plant growth, and yielddecreased. Reductions were higher in fruit yield and stomatal density in the NaCl treatment than those in Na2SO4 and CaCl2treatments. Membrane permeability was impaired with increases in all 3 forms of salt concentrations, but the effect of NaCltreatment on membrane permeability was more striking compared to the other salt forms. Proline accumulation increased withincreasing salt concentrations. The K and N concentrations decreased with increases in all 3 types of salt concentrations. Concentration of Ca decreased with increasing NaCl and Na2SO4, but increased with CaCl2 salt concentrations. The growth and yield reduction under both NaCl and Na2SO4 stress may be due to the combined effects of lower rates of Ca, K, and N, and excess accumulation of Na, while in the CaCl2 experiment the growth reduction may be related to lower rates of K and N and the high rate of Ca.