Prospectiveness of introduced species of the genus <i>Gleditsia</i> L. for garden protection plantings of the South of Russia

Abstract

The Volgograd region is considered as a southern subject of Russia, with the potential for the active development of horticulture. The ameliorative role of garden protection plantings of openwork design and the experience of introduction work on the selection of adapted woody plants for a given type of plantings are shown. The limiting climatic conditions that determine the effectiveness of the creation and functioning of gardens of various types are identified. The goal is to identify the prospects of introduced species of the genus Gleditsia L. as an assortment for garden protection plantings in the south of Russia. An integrated approach was applied to assess the effectiveness of the introduction of four species and one form of the genus Gleditsia L. under conditions of chestnut soils (collections, forest plantations in the cadastral plots of the Federal Scientific Center for Agroecology of the Russian Academy of Sciences and its branch, Volgograd Region). The natural ranges of Gleditsia L. species were identified with the allocation of USDA frost resistance zones: G. aquatica (VIb - IXb, minimum temperatures from -19 °С to -2.5 °С) and G. texana (VIIb - IXb; from -14 °С to -2,5 °С), G. triacanthos (Vа – IX zones, with temperatures from -28 °С to -5 °С). Ecological and physiological assessment showed drought resistance in conditions of moisture deficiency and high temperatures. The water content of the leaf changed slightly (about 5 %): G. caspica – 67,8 % - 62,3%, G. triacanthos – 67,2 % - 62,0 %, G. texana – 64,5 % - 60,9 %, G. japonica – 61,5 % - 57,9 %. The inventory of the forest belt with the participation of G. triacanthos revealed the differentiation of trees according to the degree of their winter hardiness: the group with winter hardiness of 3 points – 38 % of the total number of registered specimens (280); 2 points – 41 %, 1 point – 21 %. Taxation indicators and high safety (93%) of G. triacanthos plants were obtained under conditions of chestnut soils of medium and light loamy granulometric composition, which are of practical importance for calculating the reclamation effect of plantations. The results of the arealogical analysis, ecological and physiological assessment, and the study of taxation indicators made it possible to isolate the introduced species of North American origin from the Gleditsia L. polymorphic generic complex: Gleditsia texana, G. caspica, and G. triacanthos to create effective blown few-row strips.