Physiological responses of Betula pendula Roth growing in polluted areas

Plant functioning is affected by drought, extreme temperatures, heavy metal pollution and other unfavorable environmental conditions. High intensity of stress factors can be lethal to sensitive organisms or significantly decrease their condition. Intensification of stress factors is observed especially in urban and industrial areas. During the vegetative season plants purify the air and soil, decrease air temperature, increase humidity and have others psychosociological advantages. It is especially important to monitor growth of plants in areas with high anthropopression. In presented study condition of silver birch (Betula pendula Roth) growing in different stressful environments was investigated. During the research soil parameters such as pH, EC and heavy metals content were observed. Chlorophyll a fluorescence, photosynthetic pigment content, phenolic compounds concentration, ability to scavenging DPPH free radical, activity of anti-oxidative enzymes (superoxide dismutase-SOD, peroxidase-POD, catalase-CAT) were examined in the leaves to study plant response to stress factors. Investigated trees showed two types of antioxidative defense systems: with high activity of low molecular weight antioxidants (phenolics) or with high enzymatic antioxidant activity. The most stressed trees showed highest concentration of low molecular weight antioxidants (phenolics).