1. Abbasi, A. R., M. Shafi Rahmani and Y. Vafayi. 2011. Plant Biochemistry. Translation, First Printing, Tehran University Press, Tehran. (In Farsi)
2. Adiloglu, S. 2006. The effect of increasing nitrogen and zinc doses on the iron, copper and manganese contents of maize plant in calcareous and zinc deficient soils. Asian Journal of Plant Sciences 5: 504-507. [OpenAIRE]
3. Alpaslan, M. and S. Taban. 1996. Zinc-iron relationship in rice (Oryza sativa L.). Ankara university., Turkish Journal of Agricultural Sciences 2: 45-49
4. Barber, S. A. 1984. Soil Nutrient Bioavailability. A Mechanistic Approach. John Wiley & Sons, New York, NY.
5.Chen, B. M., Z. H. Wang, S. X. Li, G. X. Wang, H. X. Song and X. N. Wang. 2004. Effects of nitrate supply on plant growth, nitrate accumulation, metabolic nitrate concentration and nitrate reductase activity in three leafy vegetables. Asian Journal of Plant Sciences 167: 635-643.
6. Cumbus, I. P., D. J. Hornsey and L. W. Robinson. 1977. The influence of phosphorus, zinc and manganese on absorption and translocation of iron in watercress. Journal of Plant and Soil Sciences 78: 651-660.
7. Dejon, C. W. and W. Stekbaut. 1995. Nitrate in food commodities vegetable origin and the total diet in belgium, Ghent university. Faculty Bio-Ingenious Wetenschappen (FLTBW) 15: 625-631.
8. Durner, J. and D. F. Klessig. 1999. Nitric oxide as a signal in plants. Journal of Current Opinion in Plant Biology 2: 369-374. [OpenAIRE]
9. European Union. 2002f. Commission Regulation (EC) No563/2002 of 2 April 2002 amending regulation (EC) No466/2001 setting maximum levels for certain contaminants infoodstuffs. Official Journal 77: 1-13.
10. Hoagland, D. R. and D. I. Arnon. 1950. The water-culture method for growing plants without soil. Circular California Agricultural Experiment Station 347: 1-32.
11. Ikemoto, Y., M. Teraguchi and Y. Kogayashi. 2002. Plasma level of nitrate in congenital heart disease: comparison with healthy children. Journal of Pediatric Cardiology 23: 132-136. [OpenAIRE]
12. Jaworski, E. G. 1971. Nitrate reductase assay in intact plant tissues. Biochemical & Biophysical Research Communications 43: 1274-1279. [OpenAIRE]
13. Kacjan Marsic, N. and J. Osvald. 2002. Effects of different nitrogen levels on lettuce growth and nitrate accumulation in iceberg lettuce (Lactuca sativa Var. Capitata L.) grown hydroponically under greenhouse conditions. European Journal of Horticultural Science 67: 128-134.
14. Kirkby, E. A. 1968. Influence of ammonium and nitrate nutrition on the cation-anion balance and nitrogen and carbohydrate metabolism of white mustard plants grown in dilute nutrient solutions. Journal of Soil Sciences 105: 133-141.
15. Kotsiras, A., C. M. Olympios, J. Drosopoulos and H. C. Passam. 2002. Effects of nitrogen form and concentration on the distribution of ions within cucumber fruits. Scientia Horticulturae 95: 175-183. [OpenAIRE]