The effect of different iron concentrations on growth and elements uptake of flax (Linum usitatissimum L) under salinity stress

Plants need suitable amounts of micronutrients for optimal growth under stress conditions and this increases plant resistance to stress conditions such as salinity. In order to investigate the reaction of flax to iron application under salt stress conditions, a pot experiment was conducted as a factorial based on a completely randomized design with three replications. Salinity was determined by sodium chloride at five levels (0, 50, 100, 150 and 200 mM) and iron with 3 levels (25, 50 and 75 μM). With increased salinity, the amount of root and shoot sodium increased whereas the amount of potassium in the root and shoot decreased. The root iron concentration increased with increasing salinity up to 100 mM, and then decreased. The shoot iron concentration increased with increasing salinity up to 50 mM and followed by a decreasing trend. With increasing salinity, the amount of proline and leaf soluble sugar increased. At all salinity levels, iron had a significant effect on the amount of proline and soluble sugar. With increasing salinity up to 50 mM, the leaf soluble protein, antioxidant enzymes (peroxidase and superoxide dismutase) increased and then decreased. With increasing salinity, root and shoot dry weight decrease. To reduce the effect of salinity, the use of 50 and 75 μM iron in nutrient solutions is recommended.