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The copper (Cu) resistance of Arctostaphylos uva-ursi was tested in a pot experiment (lasting 8 weeks) using rooted cuttings originating from an area near the Harjavalta Cu-Ni smelter, SW Finland. The fine roots were moderately infected by arbutoid mycorrhizae. The plants were exposed to five Cu levels (1, 10, 22, 46 and 100 mg l(-1)) given repeatedly together with a nutrient solution. The critical Cu concentration in the nutrient solution inhibiting the growth of A. uva-ursi was below 10 mg l(-1) Cu (EC(50) value for biomass production 3.3 mg l(-1) Cu). This concentration was clearly lower than the value we have found earlier for other dwarf shrubs under similar experimental conditions. Most of the Cu given accumulated in the roots and old stems. The results suggest that A. uva-ursi cuttings were relatively sensitive to Cu despite the ability of the adult clones to grow in Cu-contaminated soil. The adult clones extend their roots into the less toxic deeper soil layers, which may facilitate the avoidance of heavy metals.

Empetrum nigrum L. (crowberry) is one of the plants surviving near the Cu-Ni 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 macronutrients and trace elements in the field and, therefore, the possible element uptake by aboveground parts of E. nigrum was studied in a greenhouse. Six different treatment solutions containing various heavy metal and macronutrient 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 concentrations in the stems, increased with increasing metal concentrations in the spraying solutions. The bark and leaves had higher heavy metal concentrations than the stems of comparable age classes. The macronutrient and Mn concentrations in E. nigrum did not change significantly with increasing element concentrations in the spraying solution. Neither the stem water potential nor the leaf chlorophyll concentrations showed any clear response to element applications. Therefore, the element uptake by aboveground parts of E. nigrum was not confirmed by this study. However, there was a tendency to a decrease in CO2 exchange rate and increase in foliar abscisic acid content in plants treated with the highest element concentrations.

The Cu and Ni tolerance of 3- to 5-year-old cuttings of crowberry (Empetrum nigrum) were tested in controlled conditions. Six levels of Cu (0.1/100 mg l-1), five levels of Ni (0/100 mg l-1) and nine levels of Cu+Ni were applied. The elongation of the shoots, new shoot and root dry weights indicated an adverse effect of increasing Cu and Ni concentrations. At low Cu levels the addition of Ni decreased the dry weights more than at high Cu levels. The resultsshow that E. nigrum accumulated high concentrations of Cu and Ni mainly in old stem tissue, which contained a maximum of over 3000 mg kg-1 Cu and 1000 mg kg-1 Ni. The concentrations ofCu and Ni in E. nigrum were higher than those measured in plants growing in areas near to Cu/Ni smelters, but the accumulation pattern was similar. The survival of the cuttings was not affected suggesting that E. nigrum possesses an internal heavy metal tolerance. [ABSTRACT FROM AUTHOR]

The copper (Cu) resistance of 1-year-old seedlings of heather (Calluna vulgaris) was tested in a greenhouse experiment. The plant material originated from seeds collected from three peatland sites located 1.2 km to the NW, and 2.5 and 5.5 km to the NE of the Harjavalta Cu/nickel (Ni) smelter, SW Finland. The plants were watered with a nutrient solution containing five different levels of Cu (1, 10, 22, 46 and 100 mg l-1). Cu clearly decreased the length growth of shoots, shoot and root biomass of C. vulgaris. More than 50% of the seedlings exposed to the highest Cu treatment died. C. vulgaris accumulated high amounts of Cu, the living old roots containing a maximum of 2200 mg kg-1 Cu and the living stems 1300 mg kg-1 Cu. Discolouring leaves contained higher Cu concentrations than green leaves. The results indicate Cu accumulation in roots and root-to-shoot transport. Some differences were found between the responses ofthe three seed provenances, but none of the populations proved to bemore resistant to Cu than the others in all the measured responses. [ABSTRACT FROM AUTHOR]