CHARACTERISTICS OF THE SHAPE ASYMMETRY OF LEAF TIP AND BASE IN POPULUS NIGRA L. UNDER INDUSTRIAL DUMP CONDITIONS

The scope of this study is to reveale the nature and variability of shape asymmetry of leaf tip and base in Populus nigra L. under conditions of two types of industrial waste dumps: coal mine and overburden rock dumps. The coefficient of shape asymmetry of leaf tip ranges from 0.000 to 0.253 in the samplings of P. nigra (in ascending order): City Park arrow right coal mine waste dumps arrow right overburden rock dumps. The coefficient of tip shape asymmetry less than 0.050 is characteristic of most leaves of all analyzed samples. The coefficient of shape asymmetry of leaf base varies from 0.000 to 0.152. This value was statistically significantly higher in the leaves sampled in the overburden rock dumps. The asymmetry coefficient of base shape less than 0.015 is characteristic of most leaves of all analyzed samples. The shape asymmetry of leaf tip and base in P. nigra is fluctuating. Among three indices analyzed (overall shape pseudosymmetry index, and coefficients of shape asymmetry of leaf tip and base), the shape asymmetry coefficient of leaf base is the most informative indicator. It is most useful for differentiation of leaf blades sampled in less degraded ecosystems and those sampled in stressful ecosystems.