Impact of Distance from Air Pollution Source on Iron Nutritional Status of Plantago major L. in Shiraz City

As an essential micronutrients, iron (Fe) has significant effect on activity of antioxidant enzymes and thereby influences the crop tolerance to environmental stresses. On the other hand, environmental stresses, i.e. air pollution might modify Fe nutritional status of plants by affecting the activity of antioxidant enzymes. The purpose of this study was to investigate the changes in Fe concentration and activity of Fe-dependent antioxidant enzymes in leaves of Plantago major L.with distance from two major sources of air pollution in Shiraz city. Oil Refinery of Shiraz (ORS) and urban traffic of Imam Hossein square were selected as two major air pollutant sources in Shiraz city. Plant leaf samples were collected at different distances from the air pollutant sources. The concentrations of Fe, zinc (Zn), chlorophyll a and b, carotenoids, and activity of catalase and peroxidase in the leaves were measured. The results showed that Fe concentration in the plant leaves increased with distance from the ORS. Leaf Fe concentration was 34.86% and 44.73 % higher in the plants at the Rokn Abbad (12 km far from the ORS) town and Melli garden (20 km far from the ORS), respectively, in comparison with those plants close to the ORS. Chlorophyll concentration increased with distance from the ORS. Activity of catalase and peroxidase was increased by distance from the ORS. For the second route, traffic of Imam Hossein square, leaf Fe concentration significantly increased with distance from the source of pollution while no regular trend was found for the changes in chlorophyll concentration and catalase and peroxidase activity. Although many factors including soil properties may be effective in this regard, considering the similarities observed in the characteristics of the studied soils, it can be concluded that there was a close relationship between the Fe nutritional status of Plantago major L. and intensity of air pollution.