ONTOGENESIS OF CHRIST’S-THORN (PALIURUS SPINA-CHRISTI MILL.)

Abstract

Background. Christ’s-thorn (Paliurus spina-christi Mill.) is a typical representative of the shibliak vegetation of the Mediterranean floristic region. This species often inhabits disturbed areas forming Paliurus-type shibliak (according to L. Adamovich) and participates in the formation of initial phytocenoses where it plays the role of an assectator. Paliurus shibliak together with Carpinus orientalis communities are considered to be one of the last and most stable stages in digression series of tree and shrub vegetation of the Mediterranean where they reinforce and protect soils from erosion. The study of P. spina-christi biology and the peculiarities of its ontogeny in natural and disturbed communities is an important task for developing a strategy for the conservation of phytocoenoses and biodiversity of the Mediterranean floristic region. Materials and methods. The research was carried out on the southern coast of Crimea, on the Black Sea coast of the Caucasus, on the coast of the Bay of Kotor (Adriatic Sea) in Montenegro. The seeds were germinated in the laboratory for study of initial stages of ontogeny; the remaining stages of ontogeny were studied from field research materials. 435 species of P. spina-christi have been analyzed. Results. Ontogenetic states and different levels of vitality have been identified and characterized; features of shoot morphogenesis have been described; the results are illustrated by figures and tables. Conclusions. P. spina-christi can be attributed to the geoxilic shrubs according to the results of the study. This species reproduces only by seeds. The following stages were identified in the morphogenesis of P. spina-christi: primary shoot, main sympodium, small tree, primary shrub, loose shrub. Signs that are significant for the determination of ontogenetic stages have been determined: the presence of cotyledons, the beginning of branching, the formation of silleptic shoots, the presence of fruiting, the intensity of fruiting, the fissuring of trunk cortex, and the death of xylopodium. Morphological multiplicity of P. spina-christi is manifested in the formation of species of different vitality and different life forms – bushlike and monocormic.

Keywords

• shibliak
• Paliurus spina-christi
• shrub
• ontogenetical state
• phase of morphogenesis
• vitality