A structural organization of the Petasites spurius (Retz.) Rchb. Roots in connection with adaptability to the conditions of variable watering

Abstract

Background. The species native to the beaches are interesting subject of research. One of them, which forms numerous populations here, is Petasites spurius. Earlier, we described the features of the internal organization of its stem. The purpose of this work is to reveal the structural organization and internal structure of the cladogenous roots of P. spurius in order to supplement the spectrum of species’ adaptations to the biotope conditions. Materials and methods. The object of the study is the root system of the species in different parts of the shoot. Anatomical and morphological studies were carried out according to generally accepted methods. Results. The secondary homorrhizal root system of P. spurius is represented by different types of adventitious roots in different parts of the shoot. On the vertical geophilic section of the shoot, they are not differentiated and die off early. In the zone of assimilating leaves, feeding roots predominate, and the number of skeletal roots is insignificant. In a horizontal geophilic area, the ratio of root types changes. In metameres located near the apical bud, the roots are undifferentiated. In the anatomical structure of the roots, minor secondary changes in the central cylinder appear in the form of the formation of individual vessels of the secondary xylem. The main functions of the roots of P. spurius are the supply of nutrients in the crustal parenchyma, and air due to the formation of large intercellular spaces. Conclusions. At the organismic level, the main adaptations were: differentiation of roots into feeding (in the assimilating part of the shoot, mainly with a feeding function) and skeletal (on the geophilic part, mainly with anchoring and storing functions); rooting of the shoot following the growth. At the tissue level the preservation of the primary stele with minor secondary changes in the conductive tissues. The main mechanisms of these transformations are: basal abbreviation in limiting the formation of xylem and terminal prolongation in the event of schizogenetic aerenchyma cavities.

Keywords

• petasites spurius (retz.) rchb.
• morphology and anatomy root
• adaptations at organ and tissue level