Growth and Mineral Concentrations of Pea Plants under Different Salinity Levels and Iron Supply

The simultaneous occurrence of several abiotic stresses is more the rule than an exception in nature. In this study pea plants were grown as hydroponics under three salinity levels (0, 50 and 100 mM NaCl), and five concentrations of iron under the form of FeEDTA (0, 0.1, 0.25, 2-optimum concentration, and 10 mg Fe/l). The separate and combined effects of both factors on growth and concentrations of in roots and shoots were studied. The combined effect of salinity and inadequate iron supply depended on the stress combination, the levels of individual stresses and the parameter under consideration. Although the decline in shoot growth for a particular combination of stress levels was close to that caused by the stronger individual stress at the same level, an additive effect of both stresses cannot be ruled out since earlier and stronger chlorosis took place under complete Fe deficiency when it was combined with salinity. It might be due to the highest Na, and the lowest Fe and N content in shoots, recorded in the plants when the highest levels of the stresses were combined. Even though salinity lessened the drop of root biomass, caused by Fe deficiency or toxicity, and some of the stress combinations resulted in closer to the control values for some nutrient concentrations compared to individual stresses, a shift in optimum Fe concentration in saline conditions was