To achieve the goal of optimizing the efficiency of micronutrient use and maximizing crop productivity, a better consideration of the processes involved in acquisition and utilization of micronutrients by plants is necessary. Nickel (Ni) is the most recently defined plant essential element and despite a wide range of effects on plant growth and metabolism, relatively little is known about its role in plant physiology and metabolism at low concentration especially in field crop species. On the other hand, plants produce a number of chelating agents including amino acids that may in?uence uptake and translocation of metals in plant. In the current study, we tried to clarify the basic mechanisms of root Ni uptake and translocation in two wheat cultivars as a consequence of the external amino acid. Our finding suggests that: (i) amino acids especially histidine (His) are effective in enhancing the contribution of symplastic to apoplastic Ni in the wheat roots, (ii) Ni(His) is most likely to be taken up as a complex via receptors at the membrane, (iii) His applied together with Ni causes the higher Ni uptake but lower H + -ATPase activity.
