Copper uptake and translocation in chicory (Cichorium intybus L. cv. Grasslands Puna) and tomato (Lycopersicon esculentum Mill. cv. Rondy) plants grown in NFT system. I. Copper uptake and distribution in plants

The uptake and distribution of copper was examined in chicory (Cichorium in tybus L. cv. Grasslands Puna) and tomato (Lycopersicon esculentum Mill. cv. Rondy) plants grown in a Nutrient Film Technique System (NFT) with additio n of 0.05, 5, 10 and 20 mg Cu L-1. Biomass production of shoots and roots o f both chicory and tomato was strongly depressed by Cu concentrations highe r than 5 mg Cu L-1 in the rooting media. Although Cu concentrations in both shoots and roots of both species increased with increasing Cu concentratio ns in the rooting media, the increase in roots was very much greater than t hat in shoots, in which the range of concentrations was small. A large prop ortion of total Cu uptake was retained by roots except when plants were gro wn in solution Cu concentrations of 0.05 mg Cu L-1. Copper retention by roo ts limited Cu translocation to xylem and shoots. Copper adsorption by the r oot appears to buffer against increases of Cu in the rooting media. A cupri c-sensitive electrode used in conjunction with total Cu analysis by graphit e furnace atomic absorption spectrophotometry (GFAAS) indicated that more t han 99.6% of total Cu in xylem sap was in a complexed form. Large differenc es between measured and predicted Cu accumulation by shoots of tomato (0.13 4-0.243 mg Cu plant(-1), 0.660-4.274 mg Cu plant(-1), respectively) and chi cory (0.095-0.203 mg Cu plant(-1), 0.626-1.620 mg Cu plant(-1), respectivel y) suggest that some xylem transported Cu is recirculated to roots via the phloem.