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In recent years, Nitrate absorption by plants, has greatly been concerned about in different countries. Some of them, have stablished standards for the amount of Nitrate concentration in edible plants. In Iran, there are few researches on this matter and because of high rate of vegetable consumption, it is necessary to be noticed. So, the primary goal of this project is to determine the concentration of Nitrate in edible parts of different plants , and then, to introduce the plants, which have the most potential for absorbing Nitrate.
In this survey, samples of Spinach (Spinacea oleracea), Leek Allium pooum), Sweet basil (Ocimum basilicum), Fenugreek (Trigonella foenum), Onion (Allium cepa), Cabbage (Brasica deracea), Lettuce Lactuca sativa), Radish Ruphanus sativens), Cucumber (C’ucum is sativa), Tomato (Lycopersicum esculentum), Potato (Solanum toberosum) and Carrot (Daucus carota) were gathered from farms of Dorcheh, Dashti, Ziar, Falavarjan, Khomieni shahr, Najaf abad (Isfahan), Khorasgan in 1999 (July, Aug., Nov.) and 2000 (May, June). In some cases, some samples with defined harvesting place were purchased from market and added to this collection. Then, Nitrate concentration in edible parts , was measured in each sample . The averages were 2865, 412, 328, 450, 428, 673, 639, 819, 30, 14, 171 and 736 mg/kg (wet weight) in spinach, leek, sweet basil, fenugreek, onion, cabbage, lettuce, radish, cucumber, tomato, potato and carrot, respectively. In these samples spinach had the highest nitrate concentration and tomato the lowest.
Nitrate concentration in Spinach was more than the WHO standard, so it’s recommended to delete it from under one year old children’s food, in order to prevent Methemoglobinemia suffering.