Aleksieieva A. Resistance of the genus Tilia L. plants in natural and technogenic ecotopes of the Steppe Dnieper

The thesis is devoted to the study of current state and to forecast of development of the genus Tilia L. plants in the natural and technogenic ecotopes of the Steppe Dnieper in the climate change conditions. An extremely high sensitivity, even to a slight increase in the aridity of the climate, was established for an aboriginal species of Tilia cordata Mill. The results of the study showed a decrease in the chlorophyll content in the leaves of T. cordata from the upper part of the slope in comparison with the lower one, as well as the correlation of the chlorophyll level with the illumination, temperature and humidity. In addition, increased accumulation of the cuticular waxes and a significant increase in the total pool of long chain high molecular hydrocarbons in their composition were detected in the sunned leaves in comparison with the shaded ones, indicating the functioning of effective mechanisms for the regulation of the biosynthesis of cuticular waxes during the adaptation of introduced species of the genus Tilia L. to the environmental conditions of the Steppe Dnieper. The changes in the activity of antioxidant protection enzymes induced by the action of the pollutants were detected in the seeds, leaves and dormant buds of the species T. platyphyllos, T. ×europaea, T. amurensis, T. tomentosa, T. begoniifolia 25 and T. cordata. Substantial rearrangement of the components of the antioxidant system in plant organs confirmed the hypothesis that the genus Tilia L. species adapt to the technogenic conditions of urban agglomerations by changing metabolic processes at all stages of ontogenesis.