Root-shoot partitioning of copper, chromium and zinc in Lycopersicon esculentum and Amaranthus hybridus grown in cement-polluted soil

摘要

Tomato (Lycopersicon esculentum) and amaranth (Amaranthus hybridus) were grown on cement-polluted soil in a greenhouse under ambient conditions and natural photoperiod. Plants were harvested two months after planting and their roots and above ground parts were cleaned and separated. Heavy metals (Cu, Zn and Cr) in roots, shoots and soil samples were determined by atomic absorption spectrophotometry. There was no significant difference in total accumulation of Cu and Zn in biomass between the two vegetables. However, significant differences in their partitioning were observed. Both vegetables exhibited large transfer of Cu and Zn from soil to roots, but translocation of Cu to above-ground parts was significantly reduced for both species. Translocation of Zn to above-ground parts in amaranth plants was relatively high, but it was restricted in tomato. Cr uptake was significantly restricted within roots of tomato whereas roots of amaranth did not accumulate Cr. These findings showed that both tomato and amaranth have a potential to absorb excessive Cu and Zn into roots, but tranlocation of Cu to above-ground parts occurred only in amaranth.