Aim and Background. Sweet basil (Ocimum basilicum) belongs to the Lamiaceae family. In this study the effect of nano iron chelated fertilizer and iron chelated fertilizer on growth parameters, leaves photosynthetic pigments, protein, and the activity of of some antioxidant enzymes in leaf were investigated.

Materials and Methods. The experiment was conducted in farm condition in the form of randomized design based on four replications. Plants were treated by different concentrations of iron chelated fertilizer (1.5 ,4.5 ,7.5 kgha-1) and nano Fe chelated fertilizer (1, 3 ,5 kgha-1).

Results. Results indicated that growth parameters increased in plants treated with Fe fertilizer (7.5 kgha-1) and nano Fe fertilizer with less than 5kgha-1. The antioxidant enzymes activity in the Fe treatments was more than nano Fe treatments. Moreover, nano iron fertilizer resulted in the reduction of protein amounts in comparison with iron fertilizer treatments.

Conclusion.The results showed that Fe fertilizer could be replaced by nano Fe fertilizer.