Фенотипічна мінливість листків рослин роду Acer, інтродукованих у степову зону України
Phenotypic variability of plant leaves of Acer genus, introduced into steppe zone of Ukraine

Summary/Abstract: This paper deals with studying of the patterns of ecological adaptation of wood species of Acer L. genus during their introduction into steppe zone of Ukraine. Hydrothermal conditions of the growing season in steppe zone of Ukraine are particularly unfavorable for tree and shrubbery plantings, comprising both native and introduced species. In the course of plants’ introduction, adaptive changes occur; such changes represent the spectrum of phenotypic implementation of the definite genotype under the influence of new environmental conditions. Stress environment of the region of introduction leads to occurrence of a great variety of phenotypic forms, as the different variants of genotype implementation. Studying of phenotypic variability gives an opportunity to determine the capacity to adaptation of introduced species and ways of adaptive reactions in new conditions of living. Therefore, objective of the work consists in studying of the processes of differentiation of morphological characters in species of Acer genus introduced in the regions of steppe zone with varying intensity of hydrothermal factors. Studies were carried out in the central and south-eastern steppe regions, as well as in the south of steppe zone in the coastal and continental areas. Subjects of research were 9 species of maples, differing by their botanic and geographic origin and by the degree of drought resistance in the steppe zone of Ukraine. Patterns of variability of morphostructural characters of leaves were determined by the indicator of specific weight of leaves which was calculated as a ratio of weight of dry laminas to their area (mg/cm2). Following the results of study, it was found that adaptation of maples to xerothermic factors of the environment is connected with changing of the ratio of groups of character variation and their contribution into total sample. Direct relationship is established between the probability density of expression (phenotypic implementation) of the character in the definite range of variation and degree of adaptation of the plant. Typical feature of species with the most prominent xeromorphic characters (A. campestre, A. tataricum, A. monspessulanum) is gradual increase in both the mean value of one of the components of the leaves’ specific weight distribution curve and its contribution in the total sample with the increasing hydrothermal stress. In maple species with low stability, probability of the character display is actually the same for each segregate component of total sample in the different regions of steppe zone, which indicates that these species has no adaptive potential to be realized in the specific environment. Eco-climatic adaptation of mesophytic maple species is displayed in reduction of confidence intervals in the segregate components of the integral curve and reduction of total interval of variation of specific weight of leaves, i.е. it is aimed at decrease in phenotypic polymorphism of introduced species of Acer genus in the drought conditions of steppe zone of Ukraine

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