Effect of different iron sources on the growth and physiological characteristics of two cultivars of lettuce in a hydroponic culture

Iron is an essential element for plant growth which is involved in many plant processes such as photosynthesis and activating enzymes involved in mitochondrial and photosynthetic electron transfer. In order to compare the effect of different sources of iron on yield and physiological characteristics of two varieties of lettuce in hydroponic culture, a complete random factorial experiment was done in Nutrition Film Technique (NFT system). The factors involved cultivar in two levels (Leaf lettuce and head gardesco) and iron fertilizer in three levels (Ferrous sulfate, Fe-EDDHA and Nano Fe-chelate, all with the 20 micro-molar concentration). The results indicated that the maximum yield and physiological parameters (Fv/Fm, PI, soluble sugars, proline, chlorophyll a, b, total and carotenoids) were obtained for the treatment of Fe-EDDHA and leaf lettuce gardesco cultivars, but the highest absorption of nutrients (iron, copper, manganese, nitrogen and phosphorus) belonged to the treatment of Fe-EDDHA and head lettuce gardesco cultivar. According to the results, it is recommended to use Fe-EDDHA chelate to increase the yield of lettuce in hydroponic systems.