EFFECTS OF CADMIUM AND SOIL TYPE ON MINERAL NUTRITION AND CARBON PARTITIONING IN SEEDLINGS OF PINUS SYLVESTRIS

摘要

The responses of Pinus sylvestris seedlings grown in organic and mineral soils in the presence of Cd were compared in order to evaluate the amelioration of Cd toxicity by soil organic matter. Low levels of ammonium acetate-extractable Cd in organic soil, compared with mineral soil, indicate a strong affinity of Cd for soil organic matter. Soil organic matter was not found to ameliorate Cd toxicity in terms of shoot growth, however Cd levels in shoots were lower in seedlings grown in organic soil than those grown in mineral soil. Root Ca and Mg concentrations were higher in organic soil. Improved nutrition of the seedlings in organic soil and organic complexing might be responsible for reduced Cd accumulation in shoots. Cd increased soluble carbohydrate concentration and decreased starch concentration in the seedlings grown in organic soil. Lower levels of total non-structural carbohydrates in the seedlings grown in the organic soil appeared to be related to an increase in stem growth.