Influence of vegetative cycle of asparagus (Asparagus officinalis L.) on copper, iron, zinc and manganese content.

The essential elements copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn) were analyzed in fresh asparagus to determine the effects of the vegetative cycle of the plant on the micronutrient content. Asparagus samples were classified in two groups by diameter (< 11 mm and > 14 mm). Asparagus from a sample group with the same diameter were divided into two portions (apical and basal) according to distance from the tip. The concentrations of copper, iron, zinc and manganese increased during the vegetative cycle of the asparagus, mainly in the apical portion which showed significantly greater concentrations with respect to the basal portion. The > 14 mm diameter asparagus presented higher levels of copper, zinc and manganese, whereas the concentration of iron was greater in the < 11 mm diameter asparagus. The mean element levels were (mg/kg dry weight): Cu, 18.9 +/- 3.9; Fe, 91.7 +/- 33.7; Zn, 69.5 +/- 24.6 and Mn, 20.9 +/- 5.0).