MORPHO-STRUCTURAL TRANSFORMATIONS OF THE ROOT SYSTEM OF SPECIES OF THE GENUS SEDUM L. DURING SEASONAL DEVELOPMENT IN THE CONDITIONS OF THE STEPPE ZONE OF UKRAINE (ON THE EXAMPLE OF KRYVORIZHYA)

Abstract

Peculiarity of the formation of the root system of species of the genus Sedum during seasonal development in the climatic conditions of Kryvorizhya are presented. The of the root system of plants served as research material S. aizoon, S. album, S. reflexum and S. spurium. The research was conducted in the Kryvyi Rih Botanical Garden of the NAS of Ukraine, the natural and climatic conditions of which are characterized by parameters common to the steppe zone, which limit the growth of plants – lack of moisture in the air and soil, abnormally high summer air temperatures. Peculiarities of the location of the root system along the soil horizons were explored taking into account the character of the physiological functions of the roots – the growth and nourishing part. The length of additional and contractile roots, the intensity of branching of lateral roots were determined. During seasonal development of plant of S. album, S. reflexum, S. spurium and S. aizoon was marked the increase of amount of nourishing roots – additional and lateral on them, which in the phase of completion of forming of superficial vegetative sphere (May) branch out to the second order, while in the phase of completion of vegetation (October) – to the third. At the end of the active sea-sonal development in plants S. album, S. reflexum the nutrient part of the root system is disposed is nearer to the surface and reach a wide lateral extension. In plants of S. spurium the nourishing roots deepen in the soil, in S. aizoon they do not change their location. The development of the growth part of the root system was marked by an increase the length of anchor and contractile roots, a slight in-crease in their number and a deepening in of the soil. The main volume of nourishing roots (up to 65%) has a lateral location in the upper layer of the soil 0–10 cm, except S. spurium for plants which it is a layer of soil 0–15 to 20 cm. The roots performing mechanical functions in the studied species reach a depth of 20–30 cm, and only in S. reflexum these roots grow to a depth of 15 cm. Additional roots in S. album, S. reflexum and S. spurium are formed in the internodes of plagiotropic ground shoots, which subsequently function as rhizomes. S. aizoon is characterized by the regrowth of addi-tional roots only in the basal part of vegetative shoots, which prevents the active spread of plants.