Life forms of subtropic plants and their modification under conditions of introduction in the Forest Steppe of Ukraine

Abstract

The taxonomic composition of the collection of subtropical plants of the Khorol Botanical Garden, consisting of 25 species: Asimina triloba (L.) Dunal, Cydonia oblonga Mill., Chaenomeles × californica Clarke ex Weber, Cormus domestica L., Mespilus germanica L., Crataegus azarolus L., Crataegus opaca Hooker & Arn., Prunus dulcis (Mill.) D.A. Webb, Prunus armeniaca L., Hovenia dulcis Thunb., Ziziphus jujuba Mill., Elaeagnus multiflora Thunb., Elaeagnus umbellata Thunb., Maclura tricuspidata (Carrière) Bureau, Ficus carica L., Passiflora incarnata L., Punica granatum L., Feijoa sellowiana O. Berg, Pistacia vera L., Citrus trifoliata L., Diospyros virginiana L., Actinidia chinensis Planch. Plants are presented in the collection areas «Garden of subtropical fruit crops», «Paradise Garden» and «Shaped Fruit Garden». The collection fund of the botanical garden was formed for a long time and each culture is at a certain stage of introduction. Subtropical fruit crops of the Khorol Botanical Garden: Asimina triloba L., Punica granatum L., Zizyphus jujuba Mill., Ficus carica L., Amygdalus communis L., Mespilus germanica L., Diospyros virginiana L. are studied as introductory populations. When creating garden compositions from subtropical species, attention was paid to the reaction of introducers to adverse weather conditions. According to the planting scheme, possible artificial forms of the plant crown are taken into account: formation of a plant with a low trunk and the same rounded crowns, in the form of spherical bushes, with main shoots-conductors formed in the form of ascending spirals. The search for the optimal life form for subtropical fruit introducers in the Forest-Steppe zone of Ukraine is carried out. The problematic moments are revealed and the ways of their solution are offered. During the modification of the crown shape, the morphological structure, peculiarities of growth and development of the introducer in new conditions, resistance to adverse weather conditions were taken into account. Asimina triloba, Cydonia oblonga, Chaenomeles × californica, Cormus domestica, Mespilus germanica, Prunus armeniaca, Ziziphus jujuba, Elaeagnus multiflora, Elaeagnus umbellate, Diospyros virginiana began to bear fruit at 6–9 years of age. The fruits have plants of typical and derived life form. This is the practical purpose of their introduction. Ficus carica, Punica have a modified life form. They are covered for the winter. It is established that most of the species composition of the collection of subtropical plants (22 species) have typical and derived life forms. 7 species: Laurus nobilis, Ficus carica, Camellia sinensis, Passiflora incarnate, Feijoa sellowiana, Punica granatum, Olea europaea in terms of introduction to the Forest-Steppe of Ukraine require mandatory modification of life form. Modification of life form is pruning, as well as warming the crown in the cold season.