Variability of morphological characteristics of Acer negundo L. in urbanized ecotops of the northern Mykolaiv region

The article investigates the morphometric characteristics of the fruits of Acer negundo L. in the conditions of urbanized ecotops of the Mykolaiv region. Acer negundo an ornamental plant from South America, which was completely naturalized in the conditions of Ukraine. As the data of the literature indicate, A. negundo actively spreads not only in the green plantations of cities, but also penetrates into the natural cenoses, displacing and oppressing the local plants. Thus, this species can be considered as invasive, which requires control over its spreading. In this regard, the actual issue is the study of the peculiarities of the seed reproduction of A. negundo and the establishment of its role in distribution of this species. Morphological parameters of A. negundo fruits are pretty changeable depending on environmental conditions, that is why there is a question of current interest in studying the variability of carpological parameters and the diapason of modifiability. The purpose of the article is to establish the characteristics of intraspecific variability of the linear morphological parameters of A. negundo. The subject of the research is variability of morphological parametres of the fruits of A. negundo urbanized ecotops of the Mykolaiv region. The work materials are results of measurements of fruits of 50 A. negundo individuals on 15 test areas in urbanized biotopes. The following carpological parameters of A. negundo were investigated: 1) angle of divergence of mericarps; 2) fruit's length and width; 3) width of winglet. The received data allowed to define criteria of variability and ecological flexibility of morphological features. Determination of the variability of morphological characters was carried out according to the technique of S.A. Mamaev. The level of variability of morphological characters (Cv) was assessed on an empirical scale: very low (<7%); low (8-12%); average (13-20%); increased (21-30%); high (31-40%); very high (> 40%). As a result of our investigations, we found the following carpological features of A. negundo. In the conditions of Mykolaiv region A. negundo shapes the fruits with the dimension of length from 3,0 to 4,8 cm (the mean is 3,5±0,02 cm) and with the dimension of width from 2,0 to 4,3 (the mean is 3,2±0,05 cm). Mericarps are located at an angle from 25º to 60º (40 ± 1º), elongated with an elongated wing, the width of which varies within 1,3 ± 0,03 cm. The established carpological features of A. negundo meets norms. On the basis of the study of linear morphological parameters of the fruits, the phenotypic variability of A. negundo individuals was revealed, which indicates the presence of intraspecies variability on these features. The most variable carpological parametrs of A. negundo are the angle of divergence of mericarps (Cv=29%) and width of winglet (Cv=34%); the most constant characteristic is the width of fruits (Cv=6%). Prospects for further research are the study of the biology of seeds reproduction of A. negundo and other representatives of the genus Acer in the territory of the Northern Black Sea region.