Variability of Tilia cordata Mill. by a complex of morphological and phenological features as a measure of environmental quality

Abstract

The article presents the findings from a long-term study on the environmental quality of the city of Yoshkar-Ola, Russia, based on an analysis of the intra-population diversity of Tilia cordata Mill. according to morphological and phenological indicators. Tilia cordata Trees have been studied at different stages of their ontogenesis, during the generative phase. The selected ecotopes differed in the degree of anthropogenic load – pollution from motor vehicles and industrial businesses. Heterogeneity of the ontogenetic groups of Tilia cordata was established by morphological and phenological features using principal component analysis. The linear size has decreased, and the leaves’ area has shown a reduction, while damage to leaves caused by atmospheric toxicants has increased in the context of urban pollution. The index of fluctuating leaf asymmetry does not differ in trees from different ecotopes. The most informative indicators of the environmental state in T. cordata specimens are morphometric - the size and number of structural components of buds and stems, and phenological - the timing and duration of phenophases. The medium-aged generative trees of T. cordata are the most sensitive to environmental pollution.