Особенности роста и развития представителей родового комплекса Robinia L в условиях интродукции

Abstract

The generic complex Robinia L. is great interest for the mobilization of genetic resources in forest protection and landscaping of the arid region. Currently wide spread in planting and forest reclamation in the South received only one kind of locust - Robinia pseudoacacia L. ( R. leachate, or black locust). The objects of research were species and forms of the genus Robinia: R. viscosa Vent.; R. luxurians (Dieck) S. K. Schneider.; R. pseudoacacia L.; R. pseudoacacia f. pyramidalis (Pepin) Rehd.; R. pseudoacacia f. unifoliola (Talou) Rehd.; R. pseudoacacia f. umbraculifera (DC) Rehd., introduced in the dendrological collections of the Volgograd region: FSC Agroecology RAS, cadastral number №34:34:000000:122, 34:34:060061:10 and the lower Volga station for selection of wood species, № 34:36:0000:14:0178. The aim of the work is to study the features of growth and development of species and forms of the genus Robinia in terms of introduction and to determine the attitude to the limiting environmental factors of the dry steppe zone of the Lower Volga Region. As a result of the research, the features of the growth and development of species and forms of the genus Robinia in terms of introduction were established, the ecological regularities of the formation of fruits and seeds were revealed, the threshold values of climatic factors in relation to the processes of life were determined, the features of growth processes in arid conditions were established. It was found that the main factors limiting the adaptation of species and forms of the genus Robinia in the dry steppe conditions of the Lower Volga region is drought and extremely high and low air temperatures (-40°, + 43°). Tolerance of plants to these climatic factors is an important indicator of the success of their introduction. Studies show that pre-existing differences in frost and drought resistance between species have been significantly reduced through gradual adaptation. This fact is explained by the high rate of adaptation of Robinia pseudoacacia to the limiting factors of the environment. Until recently, the air temperature of -25°C was considered critical for this species. As our studies have shown, this threshold in the process of acclimatization has significantly decreased and is -37°C. All studied species of Robinia have a high degree of winter hardiness in the dry steppe zone of the Lower Volga region. Less hardy turned out to be only ornamental forms of Robinia pseudoacacia f. pyramidalis (Pepin) Rehd. and Robinia pseudoacacia f. umbraculifera (DC) Rehd., propagated in culture mainly vegetative way. It is determined that Robinia can be successfully grown in different soil-geographical areas of the dry steppe zone of the Lower Volga region. Maximum size and longevity of the plantings of locust reach on Chernozem soils. The height of the plantings in the 20-year-old who-plant is 9-12 m. Planting on dark chestnut soils to 20-year-old reach 8-10 meter height, and on light chestnut-5-6 meters.