Group variability of the morphological features of the leaf of Betula pendula Roth (Betulaceae, Magnoliópsida) in the gradient of weather conditions and technogenic soil transformation

The group variability of morphological features of the leaves of Betula pendula Roth was studied in the gradients of adverse weather conditions and technogenic soil transformation. The studies were carried out on the territory of the Tagil zone of the Middle Urals in 2016–2019. It has been revealed that most of the studied leaf traits have an average level of variation, while a high one is characteristic of the shape index, and a low one is characteristic of the leaf blade index and the angles between the main and lateral vein of the first order, located in the middle and upper parts of the leaf. In the gradient of deterioration of weather conditions, the variability of the features increases, whilst it decreases in the gradient of technogenic soil transformation. The morphological features making the greatest contribution to the variability of the size and shape of the leaf were identified by the method of principal component analysis. Leaf variability is mainly determined by dimensional features. Allometric features are more stable. To assess the resistance of an organism to adverse factors, it is proposed to use the stability coefficient, which reflects the number of trait transitions from one level of variability to another one. This indicator increases both in the gradient of technogenic soil transformation and in the gradient of unfavorable weather.