Structure and functions of the types of Norway spruce (Picea abies[L.] Karst.) roots

The aim of the study was to describe variability of the structure of roots in Norway spruce (Picea abies [L.] Karst.) from their growth tips to the stem foot, i.e. anchor roots in relation to their changing functions. Histology and anatomy of plant organs were dealt with by the innumerable number of authors and fundamentals of knowledge in these disciplines have become the self-evident part of botany textbooks. The description of primary and secondary structure of roots is explained in many textbooks by means of drawings depicting the mutual position of particular systems of tissues. However, it refers mostly to the structure of herb roots in either Magnoliophytes or Liliophytes. Naturally, the structure of tree roots does not substantially differ from herb species. A certain problem is related to the secondary thickening of roots, their ramification, anastomosis and changes in the structure which are enforced by tension and pressure forces; these forces affect the roots during their mechanical load, e.g. by solifluction, soil load and compaction or through their above-ground systems. Trees can be stressed by wind gusts, snow cover, glazed frost and a number of other factors. Therefore, the structure of roots changes in the course of time as well as due to the increasing weight of the stem and crown. In terms of histological structure Norway spruce roots were studied within a forest stand in the area of the Křtiny Training Forest Enterprise, viz. Vranov Forest District (49°19´484´´N, 16°47´629´´E). Root systems were exposed with an air blast using the AIR-SPADE tool (nadezhdina, čermák 2003) and cuts of buttress roots, horizontal roots, root anastomosis and fine roots were selected. Histological studies were focused on manual transversal cuts of fine roots.