Nitrogen fertilization: Effect on Cd-phytoextraction by the halophytic plant quail bush [Atriplex lentiformis (Torr.) S. Wats]

Remediation of metal polluted sites by traditional, physical and chemical methods demands large investments of economic and technological resources compared to green remediation. Halophytic plants have been suggested to be more effective in the phytoextraction of metals from the contaminated soils compared to salt-sensitive crop plants. Pot experiment was conducted to study the accumulation of cadmium (Cd) by the Atriplex lentiformis plants when treated with different rates of nitrogen fertilizer. Nitrogen was applied to the soil at rate of 0, 100, 200, 300 and 400 mg kg− 1. Increasing the level of nitrogen from 0 to 400 mg N kg− 1 increased the dry biomass of roots and shoots of the studied plant by 75 and 27.5%, respectively. The application of N increased the chlorophyll by 100% and leaf area index by 50% and this led to increase in the photosynthesis and plant growth. The A. lentiformis plants tolerate the high levels of Cd in the soil and plant tissues. Under metal stress conditions, the studied plant contained large amount of organic compounds e.g., oxalic acid, proline and phenols. These organic compounds had negative effect on the plant growth and Cd accumulation in the aboveground parts of the plant. When 400 mg N kg− 1 was added, the chlorophyll increased by 100% and the proline, phenols and oxalic acid decreased by 33, 50 and 30%, respectively compared to the control treatment. The fertilization of A. lentiformis plants with the highest rate of nitrogen enabled the plants to remove 7.93% of the total soil Cd during a period of 105 days. Nitrogen mitigated the effect of metal stress and increased the accumulation of Cd in the aboveground parts of A. lentiformis plants. The fertilization of A. lentiformis with nitrogen could be an effective tool to enhance Cd-phytoextraction from polluted sites.