Study of the effect of iron oxide nanoparticles (nano-Fe3O4) on the morphological, biochemical and enzymatical changes of tomato plants (Cal-j N3) under cadmium stress

Research in the field of nanotechnology as an emerging field has culminated in the advancement of various branches of technology. The role of iron in reducing abiotic stresses has not been widely studied despite the fact that it is considered an essential element for plant growth. Therefore, an experiment was conducted in 2017 in the greenhouse of Kerman Graduate University of Technology. In this research, the effect of Fe3O4 nanoparticles at five levels of 0, 10, 20, 50 and 100 mg/l on tomato plant subjected to cadmium chloride (CdCl2) stress with three concentrations of 0, 100 and 200 μM was evaluated. The results showed that the 200 μM CdCl2 concentration in the nutrient solution caused a significant decrease in shoot dry weight (56%), root dry weight (65.5%), shoot length (52.6%), as well as root length (56.8%) compared to the control. Besides, MDA and H2O2 content of shoots and roots increased significantly relative to the control. The change in superoxide dismutase (SOD) activity was 232.4% (3.3-fold) in the shoot and 143.5% (2.4-fold) in the root compared to the control. However, the application of 20 mg/L concentration of Fe3O4 nanoparticles was significantly effective for plant growth and improved cadmium toxicity along with reducing the concentration of free cadmium in the plant through the stimulation of various defense mechanisms. In general, the results of this research showed that spraying iron oxide nanoparticle can be useful to protect tomato plants under cadmium stress.