Chemical composition and ecophysiological responses of Empetrum nigrum to aboveground element application

Empetrum nigrum L. (crowberry) is one of the plants surviving near the Cu-N i smelters in Finland and Russia. According to field observations, the fine roots of E. nigrum are situated below 40 cm depth and the root biomass is reduced in the polluted sites. This could cause a reduced root uptake of ma cronutrients and trace elements in the field and, therefore, the possible e lement uptake by aboveground parts of E. nigrum was studied in a greenhouse . Six different treatment solutions containing various heavy metal and macr onutrient concentrations were applied to the stems and leaves of E. nigrum and the chemical composition and ecophysiological parameters were measured. Heavy metal concentrations in the leaves and stem bark, and Cu concentrati ons in the stems, increased with increasing metal concentrations in the spr aying solutions. The bark and leaves had higher heavy metal concentrations than the stems of comparable age classes. The macronutrient and Mn concentr ations in E. nigrum did not change significantly with increasing element co ncentrations in the spraying solution. Neither the stem water potential nor the leaf chlorophyll concentrations showed any clear response to element a pplications. Therefore, the element uptake by aboveground parts of E. nigru m was not confirmed by this study. However, there was a tendency to a decre ase in CO2 exchange rate and increase in foliar abscisic acid content in pl ants treated with the highest element concentrations. (C) 2001 Elsevier Sci ence Ltd. All rights reserved.