Variability of morphometric characteristics of Betula pendula lamina under technogenic conditions of Dnipro city

The response of a plant organism to the effects of negative environmental factors, including the effects of multicomponent pollution, can be determined using a morphometric approach, setting the range of variability of biometric indicators of assimilation organs. The obtained data allow us to identify the directions of evolution of leaf shape and parameters under conditions of anthropogenic environment. The purpose of this work is to evaluate the variability of morphometric characteristics of lamina of Вetula pendula Roth. under technogenic conditions of the city of Dnipro. Leaf samples were collected in September – October 2018 at five test areas in the city of Dnipro (100 sheets each), which differed in the level of environmental pollution. For each leaf according to the method, five dimensions were measured on the left and right sides: width of the left and right halves of the leaf; the length of the vein of the second order, the second from the base of the leaf; the distance between the bases of the first and second veins of the second order; the distance between the ends of the first and second veins of the second order; the angle between the main vein and the second vein from the base of the leaf of the second order. It is shown that by the degree of increase of variation in the conditions of influence on the plants of B. pendula under conditions of multicomponent contamination of the environment the investigated signs of the lamina can be arranged as follows: 5 < 2 < 1 < 4 < 3. It is established that the most stable feature of the B. pendula lamina in the conditions of technogenesis is the angle between the main vein and the second vein from the base of the leaf of the second order, and the most variable one is the distance between the bases of the first and second veins of the second order. A tendency was found for the differences in the reactions of plants from the relatively clean area and contaminated territories: the control trees had a coefficient of variation higher for the right half of the leaf (right-sided asymmetry), whereas plants of the technogenic zones had left-sided asymmetry.