## 4 Conclusions  
This preliminary short-term study demonstrated, for the first time, the feasibility of propagating _Atriplex halimus_ through direct planting of unrooted stem cuttings in multi-metal contaminated mine tailings. Despite moderate survival rates and limited aerial biomass production after eight weeks, the species exhibited a consistent ability to root and develop in substrates characterized by high concentrations of Zn, Pb, and Cd, thus confirming its tolerance to extreme conditions.  
Two key findings emerge from our work: (_i_) direct propagation does not impair the species' capacity to accumulate trace metals in aerial tissues, with concentrations comparable to those reported for seedlings or pre-rooted cuttings in longer trials; and (_ii_) the use of compost and inert amendments improved rooting and moisture retention, though their effect on shoot biomass and metal uptake requires further investigation.  
The absence of data on root metal content limits the current ability to classify the remediation behavior of _Attriplex halimus_ as either phytoextraction or phytostabilization. Nevertheless, the accumulation of metals in above-ground biomass highlights its potential for phytomanagement applications, especially considering the possibility of recovering secondary raw materials.  
To fully assess the long-term viability and effectiveness of this approach, further field studies are needed to evaluate plant survival, growth dynamics, and metal uptake over extended periods. Future research should also explore the optimization of amendment types and doses, particularly with low-cost or site-available materials, and investigate clonal selection to enhance metal accumulation performance. Such efforts would support the development of cost-effective, scalable solutions for the ecological restoration and resource recovery of degraded mining sites.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app15137027/s1](https://www.mdpi.com/article/10.3390/app15137027/s1)]([https://www.mdpi.com/article/10.3390/app15137027/s1](https://www.mdpi.com/article/10.3390/app15137027/s1)).  
Conceptualization: M.C., A.C. and G.C. Methodology: M.C., A.C. and G.C. Validation: S.M., S.U. and G.C. Investigation: M.C. Resources: G.C. and A.C. Data curation: M.C., S.M., E.T. and G.C. Writing--original draft preparation: M.C. Writing-review and editing: S.M., S.U., E.T., A.C. and G.C. Supervision: A.C. and G.C. Funding acquisition: G.C. and A.C. All authors have read and agreed to the published version of the manuscript.  
This work is part of the research project \"REMINE-REstoration and remediation of abandoned MINE sites\", funded by the Fondazione di Sardegna and the Regional Sardinian Government (Grant CUP F7F2F16003160002).  
The original contributions presented in this study are included in the article/Supplementary Material. Further inquiries can be directed to the corresponding author.  
The authors declare no conflicts of interest.  
The following abbreviations are used in this manuscript:  
ANOVA Analysis of variance  
Cc Carotenes  
CEC Cation exchange capacity  
Chla Chlorophyll a  
Chlb Chlorophyll b  
CRM Critical raw materials  
Cx xanthophylls  
DW Dry weight  
EDTA Ethylene-diamine-tetra-acetic acid  
FW Fresh weight  
PAST Paleontological statistics  
SE Standard error  
SIN National Interest Site  
SRM Secondary raw materials