## 3 Results and Discussion
### Plants Metals Content  
At the end of the experiment, the concentrations of Zn, Pb, and Cd were determined in stems and sprouts across all treatments (CP, Control, and CP + CI), while root biomass was insufficient for metal quantification, preventing a complete mass balance assessment. Additionally, with a view toward long-term cultivation, the contents of Cu, Mg, and Mn were specifically evaluated in the CP + CI substrate. As shown in Figure 3A, Zn was the principal element accumulated in plant tissues, with concentrations significantly higher in sprouts than in stems across all treatments. The highest Zn concentration in sprouts (379.7 mg kg\({}^{-1}\)) was observed in CP, while lower but substantial concentrations were found in CP + CI (291.2 mg kg\({}^{-1}\)) and B (132.6 mg kg\({}^{-1}\)). In stems, Zn levels ranged from 170.6 mg kg\({}^{-1}\) in CP to 17.4 mg kg\({}^{-1}\) in B. For Pb, the trend was similar (Figure 3B), with the highest sprout concentration (16.6 mg kg\({}^{-1}\)) recorded in CP, followed by CP + CI (6.2 mg kg\({}^{-1}\)), and B (2.5 mg kg\({}^{-1}\)). In stems, Pb concentrations were highest in CP (17.4 mg kg\({}^{-1}\)), with lower values in CP + CI (7.1 mg kg\({}^{-1}\)), and B (2.4 mg kg\({}^{-1}\)). Cadmium concentrations (Figure 3C) were much lower than Zn and Pb, but significantly higher in sprouts than in stems in all treatments. The highest Cd concentration (1.24 mg kg\({}^{-1}\)) was found in sprouts from CP + CI, while in stems, Cd remained below 0.5 mg kg\({}^{-1}\) in all treatments. The use of amendments influenced metal accumulation in _Atriplex halimus_ aerial tissues. The highest Zn and Pb uptakes were observed in CP, while the presence of compost in CP + CI likely had an immobilization effect. This partially differs from [52], who reported no significant amendment effects for Zn, Pb, or Cd. However, regarding Cd, our results agree with both [25; 52], as no clear amendment effect was observed in this study. These patterns are consistent with previous studies on _Atriplex halimus_, where higher metal accumulation was often reported in sprouts than in stems. For example, Ref. [23] reported lower Zn (40-52 mg kg\({}^{-1}\)) and Pb (<3 mg kg\({}^{-1}\)) concentrations in _Atriplex portal  
Figure 3: Metal accumulation in plant tissues for the four treatments applied: Zn (**A**), Pb (**B**), and Cd (**C**). Different Greek letters indicate statistically significant differences between plant tissues for a specific substrate (\(p\) < 0.05); different Latin letters indicate statistically significant differences among substrates for a specific plant tissue (\(p\) < 0.05); bars indicate SE (3 replicates). _coides_, while [3, 10, 26] observed comparable or higher values in _Atriplex halimus_ grown from seeds or rooted cuttings. In field conditions, Ref. [65] reported Pb concentrations ranging from 12 to 40 mg kg\({}^{-1}\) in leaves and stems, similar to the values observed here. Higher Pb concentrations (over 200 mg kg\({}^{-1}\)) were reported by [29] in leaves of _Atriplex halimus_ after a 5-year phytoremediation trial, and Zn values up to 1200 mg kg\({}^{-1}\) were observed by [25] in field-grown plants. Regarding medium- and long-term experiments, Ref. [25] observed increasing Cd and Zn concentrations over two years, while [26] reported Pb increases over time. Refs. [10, 29] also highlighted temporal variability in metal uptake, depending on soil properties and amendment use. High genetic variability characterizes _Atriplex halimus_ species, and, for field application, using cutting to select clones represents a feasible option to standardize the plant material [3]. The short experimental duration (8 weeks) limits the assessment of long-term accumulation trends; however, selecting clones during sensitive stages, such as cuttings and young plants, could speed up the selection.