Heavy Metal Interaction for Andropogon scoparius and Rudbeckia hirta Grown on Soil from Urban and Rural Sites with Heavy Metals Additions1
- L. J. Miles and
- G. R. Parker2
Little bluestem (Andropogon scoparius) and black-eyed Susan (Rudbeckia hirta) were grown in two soils with all combinations of Cd, Zn, Pb, and Cu at two levels each for 12 weeks. Germination and establishment were completely retarded by the addition of 2,000 µg/g Zn as ZnCl2, which was due to a salt effect. Neither Cd nor Cu additions affected germination. A slight decrease in germination was noted for Pb additions of 900 µg/g which may also be associated with a salt effect. Cadmium at 10- and 20-µg/g addition rates did not affect top or root dry weight. Lead and Cu additions reduced shoot and root dry weight yields of Andropogon scoparius, root weights being more severely affected than shoot weights. Metal additions to the urban site soil did not reduce yields to the extent they did on the rural site soil. However, yields on the urban site soil control treatment were lower compared to those for the rural site control treatment.
DTPA extraction levels of heavy metals were not well correlated to plant concentrations for comparisons between the two soils. It was concluded that DTPA soil extraction may not be acceptable for metal availability comparisons among soils of differing pH.
Circumstantial evidence was found for both synergistic and antagonistic effects among the heavy metals. These were of a low level and no consistent response could be determined over species or soils.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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