Development of terrestrial biotic ligand models (t-BLM) predicting copper toxicity to wheat(Triticum aestivum) and cadmium toxicity to earthworm (E. fetia)

摘要

Terrestrial biotic ligand models (t—BLMs) predicting copper toxicity to root growth of wheat (Triticum aestivum) and effect of cadmium on survival of earthworm (E. fetia) were discussed. The extent to which Ca<'2+>, Mg<'2+>, Na<'+> and K<'+> ions each influenced Cu and Cd toxicity in nutrient solution was determined. Higher activities of Mg<'2+> and Ca <'2+> linearly increased the 2d EC50 (Cu<'2+>), while Na<'+> and K<'+> activities did not significantly influence Cu<'2+> toxicity, and higher activities of Ca<'2+>, Mg<'2+> and Na<'+> linearly increased the 48h LC50 (Cd<'2+>). Results confirmed that the protective effect of cations to metal toxicity exists in the terrestrial ecosystem, and held out the BLM hypothesis that cations compete with metal ions for the bound to the biotic ligand (BL).