Sorption of cadmium and their effects on growth, protein contents, and photosynthetic pigment composition of Veronica anagallis-aquatica L. and Ranunculus aquatilis L.

Toxic metal pollution of waters is a major environmental problem. Pollution et al. 1987), Azolla pinnata (Jackson et al. 1990), Lemna minor (Mo et al. 1989), of the biosphere with toxic metals, has accelerated dramatically since the beginning of the industrial revolution (Niriago 1979; Settle and Patterson 1980). The primary sources of this pollution are the mining and smelting of metalliferous ores, burning of the fossil fuels, municipal wastes; fertilizes, pesticides and sewage (Kanbata and Pendias 1989). Cadmium enters the aquatic environment through anthropogenic sources such as industry and agriculture (Kay et al. 1986). Cadmium is not known to be an essential element to plants. Although a limited transport of Cadmium to shoots and binding to cell walls occur in the roots (Balsberg 1989). In many ways living plants can be compared to solar driven pumps which can extract and concentrate certain elements from their environment (Raskin et al. 1994). Aquatic plants and algae are known to accumulate metals and other toxic elements from contaminated water (Wang et al. 1995). All plants have the ability to accumulate from sail and water, those heavy metals (Fe, Mn Zn, Cu, Mg, Mo and Ni) which are essential for their growth and development (Raskin et al. 1994). Certain plants also have the ability to accumulate heavy metals (Cd, Cr, Pb, Co, Ag, Se and Hg) which have no known biological function (Raskin et al. 1994; Baker and Brooks 1989). However excessive accumulation of these heavy metals can be toxic to most plants. The ability to both tolerate them to unusually high concentrations has evolved both independently and together in a number of different plant species (Ernst et al. 1992; Banuelas et al. 1990). The aquatic plants are often the first link in aquatic food chains, the metal concentrations of a few plant species have been analysed in relation to metal contents of aquatic environments (Baker et al. 1989). Some aquatic or semiaquatic macrophytes such as Eichornia crassipes (Dierberg at al. 1987) Azolla pinnata (Jackson at al. 1990), Cladophora glomerata (Mc Hardy 1990), Spirogyra fluviatilis (Saygideger, 1998) can take up Zn, Pb, Cu, Cd Fe and Hg from contaminated solutions. They are also known to be tolerant to these metals. This study was carried out to investigate, the short-term uptake of Cd by Veronica anagallis-aquatica L. and Ranunculus aquatilis L. Effects of Cadmium on growth, protein contents and photosynthetic pigment composition, as well as to determinate tolerance to Cadmium were investigated.