The dynamics of fluctuating asymmetry	of Acer platanoides L. leaves in urbanized environment
Authors: Gavrikova V. S. , Ignatyuk O. A. 
Published: February 2018

The paper discusses the investigation of stability of developmental processes of vegetative organs of Acer platanoides L. trees from different habitats (derivative of natural stands and managed plantations). Developmental stability (instability) is appraised based on the value of the index of leaves fluctuating asymmetry. The various aspects of the dynamics of fluctuating asymmetry of Acer platanoides L. leaves are discussed from the perspective of its using with the purpose of bioindication of urbanized environmental state. The method of the detection of fluctuating asymmetry values of A. platanoides leaves using the five original morphological parameters that are well detected on recently collected leaves and can be successfully measured on the digital image is developed and suggested by authors. Modification of the method (namely, measuring by using the digital image) is admitted to avoid long-termed measuring the recently collected leaves which will wither quickly enough and change its shape and size. It is established, that there is no significant differences of asymmetry of individual leaves within the tree. The series of experiments in the “Feofania” was investigated with the purpose of studying the patterns of the dynamics of fluctuating asymmetry during the season. The assays from the same nine trees were collected in May (directly after the leaf-forming), June, July. It is showed, that the fluctuating asymmetry values of A. platanoides leaves are not changed reliably (p=0,05) within the tree and the whole habitat during the season. Therefore, biomonitoring and bioindication using the fluctuating asymmetry of leaves can be conducted at the beginning and the end of the vegetative season. The three years dynamics of fluctuating asymmetry values of A. platanoides leaves from eight habitats in Kyiv is investigated. During three years the value of fluctuating asymmetry is varied in the short interval – from 6 % to 8 %. It is founded, that the tendency of changing the fluctuating asymmetry values is different for various habitats. The fluctuating asymmetry value of A. platanoides leaves for four habitats (“Feofania”, “Lysa Gora”, “Goloseevskiy Park”, “Desnyanskiy Park”) of the eight investigated decreases during the 3-year period. The highest values are recorded for three habitats (“Pushcha-Vodytsia”, “Vossoedinenia Avenue”, “Siretskiy Grove”) in 2012. The tendency of the asymmetry increasing during the whole period of investigation is recorded in only one habitat (“Ivana Kudri Street”). The fluctuating asymmetry value in 2013 is lower than the value of this parameter in 2012 in seven of the eight habitats (except “Ivana Kudri Street”). The averaged annual fluctuating asymmetry values in all habitats of the megalopolis also suggest that there is a slight decrease of the asymmetry value in 2013 in comparison with previous years. Discovered differences of the fluctuating asymmetry values of A. platanoides leaves in studied habitats in different years show the tendency, which does not give the clear picture. Apparently, it is connected with the certain constellation of existing natural and anthropogenic factors. To discovery its regularity the more prolonged and profound investigations should be conducted. Therefore, to get representative results of monitoring we recommend conducting the bioindication with using the fluctuating asymmetry values of A. platanoides leaves during several (minimum three) years running. The comparison of the averaged (during three years) values of the fluctuating asymmetry of every habitat and the averaged value of the whole megalopolis shows normalized results. The habitats “Desnyanskiy Park” and “Vossoedinenia Avenue” demonstrate reliably higher fluctuating asymmetry. There is also the similar fluctuating asymmetry value of leaves from habitat “Ivana Kudri Street”. The averaged fluctuating asymmetry values of leaves from habitats “Siretskiy Grove” and “Goloseevskiy Park” are reliably lower than the averaged value of the megalopolis. Therefore, the highest values of the fluctuating asymmetry of A. platanoides leaves, which show the least stable developmental processes of plants, are founded on the territories, that have the maximum level of urbanization. These habitats are managed plantation. The others investigated habitats are natural stands. It is detected, that the fluctuating asymmetry value of A. platanoides leaves decreases when proportion of its dominance in the stands increases. It should be appreciated when choosing the control group of plants during the monitoring. The control group should be from the natural stand with the maximum dominance of the relevant species.