砂漠植物におけるカドミウム蓄積の比較分析：植物修復における種選択への影響

This study systematically investigates cadmium (Cd) accumulation and translocation mechanisms in woody plants through integrated analysis of 16 species. Roots consistently exhibited the highest Cd concentrations (0.26 ± 0.13 mg/kg), serving as primary accumulation sites, while bark functioned as a critical secondary storage organ (0.22 ± 0.09 mg/kg) with strong physiological coordination to roots (r = 0.72, p < 0.001). Leaves demonstrated strict Cd restriction (0.09 ± 0.05 mg/kg) and low variability (CV = 48.7%), indicating evolutionary adaptations to minimize phytotoxicity in photosynthetic tissues. Three functional groups were identified: hyperaccumulators (e.g., Ulmus pumila, root/leaf ratio = 6.37), excluders (e.g., Malus spectabilis, root/leaf ratio = 1.12), and intermediate species (e.g., Syringa oblata) with balanced translocation patterns. Strong root-bark correlations (r = 0.68) and negative stem-leaf associations (r = -0.42) revealed complex interorgan translocation dynamics. Cd speciation analysis showed dominant residual fractions in soils (60-80%) and elevated water-soluble or weakly bound Cd in roots (35-52%). These findings provide a mechanistic basis for designing species-specific phytoremediation strategies, including phytoextraction and ecological stabilization. It will identify suitable tree species for effectively stabilizing or containing the metal pollution within a defined area, thereby preventing its lateral spread or leaching.