Effect of Aluminum on the Growth and Nutrition of Tulip-Popular Seedlings

Spurred by concern about aluminum (Al) mobilized in soil by acid deposition, the sensitivity of tulip-poplar tree seedlings to aluminum was studied. Seedlings were exposed to one of four concentrations of Al in a sandy soil. Shoot and root biomass reductions were observed at the lowest concentration used (200 mu M). Multivalent cation concentrations in leaves and roots declined, and magnesium concentrations in roots was reduced significantly. At higher Al concentrations, calcium levels in leaves dropped. Al appears to alter translocation of calcium and magnesium to shoots and accumulation of magnesium in roots. Tulip-poplar trees may have a low threshold for Al toxicity and could show adverse effects from exposure to elevated acidic deposition and Al.