Organic Matter Influence in Cadmium Uptake by Sorghum

Abstract

The influence of soil organic matter (OM) in the uptake of cadmium (Cd) by Sorghum will be studied in order to get a better knowledge in the yield and understanding of detoxification mechanisms of soils. Plants were grown for 60 days in a greenhouse pot experiment using a contaminated soil with 4.5 and 35 mg Cd kg⁻¹, in absence and presence of OM. An Irish peat moss (70 g kg⁻¹ of soil) was added as OM. In the presence of OM the biomass production of root and shoot was increased with a positive correlation between biomass increment and contamination level. For experiments with 35 mg Cd kg⁻¹ of soil the biomass production was increased of about 7 times in the presence (vs. absence) of OM. Although the presence of OM had decreased Cd root concentration by decreasing Cd bioavailability in soil, the increase of biomass in presence of OM led to an increase of about 3 times on the Cd amount in shoot, result that can be important in soil phytoremediation.

Keywords:

• Cadmium
• Organic matter
• Photoextraction
• Sorghum

Acknowledgments

This work is under the Research Project PRAXIS/P/QUI/10034/98 of FCT. It has also the financial support supplied by the Portuguese Education Ministry through the PRODEP II–Ph.D. fellowship.