Cadmium tolerance and distribution patterns in three perennial herbaceous plant species: Implications for phytostabilization potential

Abstract To evaluate the phytostabilization potential of perennial herbaceous species in cadmium (Cd)‐contaminated soil, Cd tolerance and distribution were assessed in a 90‐day pot experiment under 0–100 mg/kg Cd. Crested wheatgrass ( Agropyron cristatum (L.) Gaertn.), orchardgrass ( Dactylis glomerata L.) and Siberian wildrye ( Elymus sibiricus L.) were tested. The final germination percentage, shoot length, root length, and root‐shoot ratio of A. cristatum did not differ significantly among the control and Cd treatments. In D. glomerata , germination, growth, chlorophyll content, and root activity decreased significantly at 50 and 100 mg/kg Cd. By contrast, E. sibiricus displayed trait‐specific positive responses: germination percentage, shoot length, root length, and root biomass increased significantly at 50 mg/kg Cd, while root volume, shoot biomass, chlorophyll content, and root activity increased significantly at both 50 and 100 mg/kg Cd. Based on the root‐length tolerance index, Cd tolerance ranked as E. sibiricus > A. cristatum > D. glomerata . Malondialdehyde (MDA) content, relative conductivity, and Cd concentrations in shoots and roots increased with increasing Cd stress and were significantly higher at 100 mg/kg Cd than in the control, indicating high‐Cd injury. Bioconcentration factors exceeded 1 and were higher in roots than in shoots, whereas translocation factors remained below 1, indicating root‐dominant accumulation and limited aboveground translocation. Membership function analysis integrating Cd tolerance and distribution traits ranked phytostabilization potential as E. sibiricus > A. cristatum > D. glomerata . These results support Cd phytostabilization screening, although field validation remains necessary.