Cadmium Accumulation and Tolerance of Two Salix Genotypes Hydroponically Grown in Presence of Cadmium

ABSTRACT

Two Salix genotypes (Salix alba, clone LUC-31—genotype I and Salix viminalis, clone STOTT—genotype II) were grown hydroponically for 14 d at increasing concentrations of cadmium (Cd) (0, 5, 10, and 15 μM) in order to study both Cd accumulation and genotype tolerance. Growth responses, photosynthetic performance, activities of metal-responsive enzymes, and changes in some nutrients content were used as evaluation criteria. The Genotype II assimilated more Cd (maximum leaf concentration 47.8± 2.9 mg Cd kg⁻¹ DW) compared with the Genotype I and, based on both morphological (root length, total biomass) and metabolic indicators (photosynthetic performance, activities of metal-responsive enzymes, changes in several nutrients), was classified as less tolerant to this heavy metal. However, it is considered to be more suitable for Cd phytoextraction, as it would compensate for its somewhat lower tolerance with its higher Cd accumulation, as well as its higher productivity under field conditions.

Keywords:

• cadmium
• Salix
• mineral nutrients
• enzyme activities
• leaf gas exchange
• photosynthetic pigments

ACKNOWLEDGMENTS

The support from NATO Science Fellowships Programme (BELGIUM) in providing a postdoctoral grant to Andon Vassilev and from Comunidad Autonoma de Madrid-European Social Fund in providing a postdoctoral grant to Araceli Pérez-Sanz is acknowledged.