Life forms of lombardy poplar (Populus Italica (Du Roi) Moench) in quarry and dump complexes of Kryvyi Rih area

Objective — to ascertain the variety of life forms of Populus italica (Du Roi) Moench, naturally inhabiting quarry and dump complexes of Kryvyi Rih area.

Material and methods. In the quarry and dump complexes of iron-ore productions of Kryvyi Rih area, we defined the origin of plants of P. italica, places of their growing; substrate where they grow, and their age. Life forms of P. italica were classified in obedience to A.A. Chistyakova (1987, 1988). We digged out plant rootage, determined the amount of root offspring, their age, height and diameter of above-ground orthotropic shoots.

Results. Because of multi-optional progress during ontomorphogenesis, P. italica can be presented in the adulthood by some life forms: single-trunked tree, few- and multi-trunked tree or tree-bush, clump-forming tree, depending on different ecotopes. A single-trunked trees do not occur often, mainly they are trees of seed origin on the rocky slopes of old dumps in the places of soil washing-off in deepening and gullies. For such individuals, we noted a less height, habitus of crown as compared to the plants of undisturbed habitats, and also less general duration of ontogenesis or his separate periods. Little-trunked forms consist of 2–3 trunks of similar diameters, multi-trunked – from 7–11 trunks. Such life form of P. italica appears as a result of progress of shoots from the asleep buds in basale part of immature and virginil plants and as a result of progress of root shoots. In the even areas of iron-ore dump and quarry complexes, P. italica often forms life form — clumpforming tree – during ontogenesis. Such trees consist more than 90 % of number of self-inhabited plants in the dump of the Pershotravnevyi mine. The maternal individuals were 20–25-year-old, their height varied from 11 to 19 m, and the trunk diameter – from 26 to 34 cm. Area occupied by the root shoots of clump-forming tree of P. italic varied from 25 to 250 m². The root underwood of P. italica on iron-ore dumps spreads on all directions from a maternal individual and a to 15–20 m can appear in the distance from her. The clump-forming trees of P. italica, being a complex individuals, consist of the united partial formations arising up as a result of branching of superficial roots of 3–5-year-old root shoots with subsequent formation of underwood. These formations can move away from a maternal individual and prove as independent individuals.

Conclusions. The individuals of P. italica of seed origin in dumps and sides of quarries of Kryvyi Rih area stand out with high vitality and because of multioptional progress, can be presented in the adulthood by different life forms. Most often P. italica on iron-ore dumps forms such life form as clump-forming tree due to annual formation of root underwood. As a result the general assimilative surface of such complex individuals increases. Such behavioural strategy of P. italica is an adaptive response to the unfavourable terms of growing in the quarry and dump complexes of Kryvyi Rih area.