Home – Home – Jornals – Contemporary Problems of Ecology 2025 number 1

The results of an anatomical description of a cross section of a shoot of Juniperus oblonga M.Bieb are presented., affected by Arceuthobium oxycedri. The anatomical structure of a healthy shoot of J. oblonga was compared with the description of the stem of J. communis L. according to literature data, and distinctive features in the structure were noted. It was noted that shoots of J. oblonga are affected by A. oxycedri up to 12 years of age. The depth of penetration of the haustorium depends on the age of the affected shoot; when young shoots are affected, the connection of the haustorium with the xylem is detected up to the perimedullary part of the pith. The haustorium is pointed towards the center of the stem and expanded towards the crustal part and joins the xylem obliquely towards the apex of the stem. At the base of the arceutobium shoot, at the site of its penetration into the juniper bark, “root cups” are formed. n the shoots of J. oblonga affected by A. oxycedri, in the places of penetration of haustoria, the shoot xylem grows, which is the result of activation and synchronization of the work of the cambium of the host plant and the haustorium of the semi-parasite. The growth of xylem occurs due to an increase in the number of layers of the early spring part of the xylem of the stem. The connection of the xylem and phloem of the juniper stem with the conducting system of the hemiparasite is carried out through disjunctive fragments of the haustorium. Each above-ground shoot of Arceutobium has its own haustorial system, not connected with other shoots, which enters the bark part of the stem and rests on the “root cup”. By eight to twelve years of life of the juniper stem, the ectophytic part of the semi-parasite system is destroyed, only “root cups” remain on the surface of the juniper bark, and excessive thickening of the shoot stops.