Physiological reaction of basket willow (Salix viminalis L.) to copper excess in hydroponic medium

The influence of copper salt, in a concentration range of 50–150 mg·dm⁻³, on the physiological response of basket willow was studied on Tora variety, which were grown in hydroponics. Content of assimilation pigments, relative water content (RWC), water saturation deficit (WSD), intensity of assimilation and transpiration, stomatal conductance, photosynthetic rate of water use efficiency (WUE) and instantaneous photosynthetic rate of water use (WUEI) were determined in leaves. It was observed that the decrease in the concentration of tested physiological parameters correlated with the increase in copper salt doses in the medium. The assimilation and transpiration of basket willow were significantly limited by stomata. The addition of copper salt to the medium increased WSD in leaves of the basket willow. The obtained results of the studied physiological parameters may prove useful for the assessment of resistance of the studied willow cultivar to stress caused by increased copper ion content in medium and its applicability in reclamation of areas degraded by humans.