Оценка древесных растений Juniperus L. для озеленения урбанизированных территорий малолесных регионов

Abstract

Monitoring studies of plant objects provide an array of data on the characteristics of growth, phenology, the development of generative organs, the specifics of fruiting, seed quality, and resistance to stress factors, i.e. indicators that are in a functional relationship with each other and allow estimating the degree of environmental plasticity of plants. To justify the prospects of species of the Juniperus genus, forecast the adaptability level of species outside the natural range, reliable and relevant information on the success of adaptation of introduced plants in urbanized areas of sparsely wooded regions is necessary. The purpose of the research is to justify the prospects of using species of the Juniperus genus based on the study of their biological potential under the conditions of introduction. The objects of research were species of the Juniperus genus: J. virginiana L., J. sabina L., J. communis L. and their forms introduced in dendrological collections of the Volgograd Region: Federal Research Center of Agroecology of the Russian Academy of Sciences, Cadastre No. 34:34:000000:122, 34:34:060061:10 and the Lower Volga tree breeding station, No. 34:36 0000:14:0178. The survey was conducted by the route method. The seasonal development rhythms of introduced plants were studied by the method of phenological observations. The characteristics of decorativeness, growth, and development of three species of Juniperus L. (J. sabina L., J. virginiana L., J. communis L.) in chestnut soils of the Volgograd Region, the assessment of reproductive ability, and the reproduction specifics of various cultivated species culture were revealed according to the methods of the Federal Scientific Center of Agroecology of the Russian Academy of Sciences. To determine the fruiting specifics of the study objects, the method of determining the mass of 1000 seeds was used; weighing was performed using a MASSA-K brand balance. For mathematical data processing, standard algorithms were used: the arithmetic mean with absolute and relative errors; the coefficient of variation to assess the characteristics of reproductive processes; the significance of differences between individual indicators. The characteristics of decorativeness, growth, and development of three species of Juniperus L. (J. sabina L., J. virginiana L., J. communis L.) in chestnut soils of the Volgograd Region are described. An assessment of reproductive ability is given, the features of reproduction of various cultivate species are revealed. According to the complex of the studied quantitative indicators of the seed material, it was found that the weight of seeds of Virginian juniper (Juniperus virginiana L.) (10 g) was almost half of the weight of common juniper seeds; the weight of the seeds of savin juniper (Juniperus sabina L.) (24 g) exceeded the weight of the seeds of common juniper by 1.5 times and that of Virginian juniper – by 2.5 times, in comparison with the standard data for common juniper (weight of 1000 pcs. – 16 g). A study of the fruiting specifics of Virginian juniper (J. virginiana) showed that 10.0 grams of conifer berries contained an average of 156 berries and 270 seeds, the yield of pure seeds was 15.84% of the fruit weight; 10.0 grams of cone berry of savin juniper (J. sabina) contained an average of 86 berries and 170 seeds, the yield of pure seeds was 20.09% of the fruit weight. It has been established that for landscaping the urban areas of the Volgograd Region, Juniperus virginiana is recommended to be used in alley stands, in clean groups, and as a second tier in the stands of Betula, Robinia, Pseudotsuga, Larix. Juniperus sabina is most valuable for decorating and strengthening slopes. In gardens and public parks, its use is limited, and when planting children's institutions, it is excluded (needles and fruits are poisonous). In the Volgograd Region, Juniperus communis and its forms can be used on poor sandy soils in group plantings, at the edges, and in molded hedges. Pyramidal forms are suitable in the level spaces, dwarf forms – for the design of rocky areas. The form with a golden color can be used in small groups on lawns.