Morpho-Physiological and Ecological Characteristics of Melilotus officinalis (Fabaceae, Magnoliopsida) in the Conditions of the Republic of Tatarstan

Abstract

The morphological variability of the aerial vegetative and generative organs of Melilotus officinalis in the ecotone communities of the forest-steppe zone, the forest zone of the Republic of Tatarstan including desecrated parts of the forest zone was studied. The ascorbic acid content in various parts of the plants growing in these habitats was also analyzed. It was revealed that the realization of the morpho-physiological potential of plants was determined by the conditions of botanical-geographical zones. The sweet clover, growing on black soils under the conditions of ecotone communities of the forest-steppe zone, was found to have higher indicators of “total biomass”, “biomass of leaves”, “biomass of inflorescences”, etc., as compared to the plants from similar communities growing on gray soils of the forest zone. Under the conditions of the ecotone communities of the forest-steppe zone, the content of ascorbic acid in all parts of the plant was also higher. Melilotus officinalis, growing in the conditions of a desecrated soil layer, was characterized by the maximum realization of its biomorphological potential with a low value of the coefficient of variation (CV), which reflected a stronger homogeneity of the samples. In the plants growing under extreme conditions, a sharp increase in the concentration of ascorbic acid in all parts was observed, which could be considered as an important mechanism for the adaptation of the species to survival under conditions of a sharp temperature difference of the substrate. Along with an increase in the generative period, an important component of the species adaptation was the low correlation between the indicator “biomass of inflorescences” and the concentration of ascorbic acid in inflorescences, “biomass of inflorescences” and the concentration of ascorbic acid in the leaves, which reflected the stable process of formation of the generative system of sweet clover. All coenopopulations were characterized by an incomplete ontogenetic spectrum with an absolute maximum on the plants with the middle-age ontogenetic status (95%).