Phytoremediation potential and heavy metal bioavailability responses of native <i>Aristida</i> species under chromium and lead stress

Heavy metal (HM) contamination threatens ecosystem health and agricultural sustainability, particularly in arid and semi-arid regions. This study assessed the phytoremediation potential of two native grasses, Aristida hystrix and Aristida adscensionis, under chromium (Cr; 20, 40, 80 µM/L) and lead (Pb; 50, 200, 400 µM/L) stress in a six-week hydroponic experiment. Growth, biomass, chlorophyll, transpiration, and relative water content (RWC) were evaluated using two-way ANOVA, Pearson correlation, and PCA. Both metals significantly reduced growth and biomass, confirming dose-dependent toxicity. Pb markedly decreased transpiration and chlorophyll, particularly in A. adscensionis, indicating greater sensitivity, whereas A. hystrix maintained higher RWC, reflecting stronger stress tolerance. Despite reduced growth, both grasses survived and tolerated heavy metal exposure, demonstrating their potential for phytostabilization and sustainable restoration of contaminated soils in arid environments.