Differing effects of cadmium on two varieties of cottonwood Populus deltoides Bartr.

Abstract

Two varieties of cottonwood, Populus deltoides Bartr., were grown under greenhouse conditions in soil treated with differing amounts of cadmium chloride to compare various parameters of growth and uptake. Concentration levels of 5, 25, 100 and 200 μg Cd/g soil were established with a control treatment in individual 17·8 cm diameter plastic pots filled with a 1:1 mixture of Grantsburg silt loam and ‘Perlite’.

Plants were germinated and grown through one growing season of 14 weeks. Following harvest, cadmium concentrations were determined in leaf, stem and root tissue by atomic absorption spectrophotometry. Leaf, stem and root biomass, height and percent survival of the seedlings were also determined.

The two varieties studied were found to differ significantly in cadmium allocation to roots and stems and in percent survival. Leaf and root biomass and cadmium concentration of leaf tissue were found to be predominantly controlled by the cadmium level of the soil but were not variety-dependent. Stem biomass and height were variety-dependent but did not differ as a result of soil cadmium concentration.