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Farmland soil typical for the Polish rural environment was used in pot experiment to estimate the impact of cadmium and zinc on the manganese, lead and copper uptake by lemon balm (Melissa officinalis L). Bioavailable and total forms of investigated metals in soil and metal concentrations in plants were determined by atomic absorption spectrometry. The plant photosynthesis indicators were also examined. Intensification of photosynthesis upon the high zinc and cadmium soil supplementation was observed. This effect was not detected at low metal concentrations. ANOVA proved that cadmium and zinc treatments influenced manganese, lead and copper transfer from soil and their concentration in plants. Zinc uptake and accumulation in either roots or above-ground parts in plant was inversely proportional to cadmium concentration in soil. Manganese concentration in roots decreased upon the soil supplementation with either zinc or cadmium. It suggests that the latter ions are transported via symplastic pathways and compete with manganese for similar transporters. The opposite situation was observed for lead and copper. Soil supplementation with cadmium and zinc affects manganese, lead and copper concentrations and photosynthesis intensity in lemon balm plant. The following combined interactions in either normal or stress conditions are important indicators of the migration pathways.

Lemon balm ( Melissa officinalis ) is a popular herb widely used in medicine. It is often cultivated in soils with substantial heavy metal content. Here we investigate the associated effects of cadmium and copper on the plant growth parameters augmented by the manganese, zinc, and lead uptake indicators. The concentration of all elements in soil and plants was determined by the HR-CS FAAS with the ContrAA 300 Analytik Jena spectrometer. Bioavailable and total forms calculated for all examined metals were augmented by the soil analyses. The index of chlorophyll content in leaves, the activity of net photosynthesis, stomatal conductance, transpiration rate, and intercellular concentration of CO 2 were also investigated. Either Cd or Cu acting alone at high concentrations in soil are toxic to plants as indicated by chlorophyll indices and gas exchange parameters. Surprisingly, this effect was not observed when both metals were administered together. The sole cadmium or copper supplementations hampered the plant's growth, lowered the leaf area, and altered the plant's stem elongation. Analysis of variance showed that cadmium and copper treatments of lemon balm significantly influenced manganese, lead, and zinc concentration in roots and above ground parts.