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

摘要

The uptake and distribution of copper was examined in chicory (Cichorium intybus L. cv. Grasslands Puna) and tomato (Lycopersicon esculentum Mill. cv. Rondy) plants grown in a Nutrient Film Technique System (NFT) with addition of 0.05, 5, 10 and 20 mg Cu L-1. Biomass production of shoots and roots of both chicory and tomato was strongly depressed by Cu concentrations higher 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 concentrations in the rooting media, the increase in roots was very much greater than that in shoots, in which the range of concentrations was small. A large proportion of total Cu uptake was retained by roots except when plants were grown in solution Cu concentrations of 0.05 mg Cu L-1. Copper retention by roots limited Cu translocation to xylem and shoots. Copper adsorption by the root appears to buffer against increases of Cu in the rooting media. A cupric-sensitive electrode used in conjunction with total Cu analysis by graphite furnace atomic absorption spectrophotometry (GFAAS) indicated that more than 99.6% of total Cu in xylem sap was in a complexed form. Large differences between measured and predicted Cu accumulation by shoots of tomato (0.134-0.243 mg Cu plant(-1), 0.660-4.274 mg Cu plant(-1), respectively) and chicory (0.095-0.203 mg Cu plant(-1), 0.626-1.620 mg Cu plant(-1), respectively) suggest that some xylem transported Cu is recirculated to roots via the phloem.