Cadmium-uptake by aquatic plant Hygrophila corimbosa stricta
1999
Damiano, C. | Starza, S.R. la | Frattarelli, A. | Giorgioni, M. (Fruit Trees Research Inst., Rome (Italy). Propagation Department) | Figliolia, A. | Ferrazza, P. | Marcussi, A.
Heavy metal pollution in soil and water has becoming a serious problem for agriculture and health. Some heavy metals are natural micronutrient in the vegetable kingdom; they are rapidly absorbed by roots and translated into whole plant. The toxic effect is checked when the heavy metals concentration in soil is higher than the normal trace amounts. However, many species developed some physiological mechanisms that allow the survival also in that status. Physiological studies on plants able to live also in presence of high concentration of heavy metals have explained the metals attachment and binding as main mechanisms for detoxification. The main classes of intracellular ligands for heavy metals are organic acids (malic acid and citric acid are essential for Zn detoxification). Aquatic plants appear a good cure for heavy metals accumulation and, therefore, for water detoxification. As to that presented in literature, some of them are well known to be able to accumulate pollutants (Cd, Co, Pb, Hg, Cu, and Zn). For our experiments we used aquatic plant Hygrophila corymbosa "Stricta" (Acanthaceae), grown in vitro on agar medium containing CdSO4. Since the concentration of Cd in the natural environment exceed 1.13 ppm very rarely; we adopted a range of concentration between 0 and 5.63 ppm, as treatments. This plant was selected because of its high attitude to in vitro regeneration from leaf disks. After in vitro multiplication, a curve of tolerance to cadmium, from 0 ppm to 5.63 ppm (CdSO4) was determined.
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