engleski

Trace elements deposition in radish plants grown in salt-affected and Cd-contaminated organic soil.

Soil degradation under excessive salinity and pollution by potentially toxic metals are increasing rapidly in agricultural areas, representing a serious threat to food production and human food security. A factorial combination of four salt concentrations (0, 20, 40 and 60 mM NaCl) and three cadmium (Cd) levels (0.3, 2.5 and 5 mg kg-1) in peat soil on mineral uptake/distribution in radish plants (Raphanus sativus L. var. sativus) was studied under the greenhouse conditions. After 34 days of exposure to increasing NaCl concentrations, plants proportionally increased Na and Cl accumulation in leaf and hypocotyl tissues. Salinity significantly increased accumulation of Cd (up to 20%), Cu (up to 11%) and Zn (up to 7%) in leaves. In contrast, raising salinity levels did not affect Cd and Cu translocation from leaves and deposition into the edible hypocotyls, which may indicate that the phloem mobility of those elements in radish plants is relatively poor and unaffected by NaCl exposure. Increasing salinity improved Zn accumulation in the hypocotyl tissue up to 27%. Soil contamination by Cd resulted in 10-fold increases of Cd content in leaf and hypocotyl tissues, and significant decreases of Zn and Cu content in leaves. Cu and Zn deposition in radish hypocotyls was unaffected under saline conditions. Leaf accumulation of all observed metals (Na, Cd, Zn and Cu) exceeded their accumulation in edible tissues, suggesting that the apoplast and the vacuoles of leaf cells may be the sites of preferential deposition of these metals.

salinity; Cd; Zn; Cu

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