Mechanisms and Strategies for Phytoremediation of Cadmium

INTRODUCTION
    Phytoremediation
    Advantages of  Phytoremediation
    Limitations of Phytoremediation

BIOAVAILABILITY OF CADMIUM 
    Cation Exchange Capacity (CEC)
    pH
    Soil Amendments
    Competitive Cations
    Fertilizer
    Mycorrhizae
    Chelation
       Phytochelatins (PCs)
       Phytochelatin Effectiveness
       Role of Sulfur in PCs
       Oxidative Stress
       Translocation
       Metallothioneins
       Organic Acids
       EDTA / EGTA

CADMIUM TOLERANCE AND
ACCUMULATION IN PLANTS
    Cell Wall Binding
    Reduced Transport
    Compartmentalization
    Chelation
    Phytoextraction factors
       Table 1.  Plant Accumulation
       Hyperaccumulators

CONCLUSIONS

LINKS

BIBLIOGRAPHY

CONCLUSIONS

      Cd phytoextraction is apparently a viable option of remediating Cd-laden soils. Addition of chelators such as organic acids, EDTA and EGTA, altering soil pH, fertilizing appropriately with NH4, K and P, adding sulfur to increase glutathione activity, investigating mycorrhizal and microbe roles and perhaps utilizing biotechnology to increase biomass of hyperaccumulators and/or increase accumulation in high-biomass species are all proven methods of impoving Cd-phytoextraction. Specific biotechnological solutions include over expressing glutathione, blocking expresson of H+/Cd2+ antiports, increasing organic acid production, over expressing phytochelatin synthase and increasing antioxidant activity inside the cell.

     The most practical solution currently available for Cd-cleanup is argueably EGTA-assisted phytoextraction using a high-biomass / high- accumulating species.

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Page Created 4-18-00
Sam Cox
Department of Horticulture
Colorado State University
samcox@lamar.colostate.edu
http://lamar.colostate.edu/~samcox/index.htm