Analysis of morphometric characteristics of leaf blade in ge-nus Lycopus exemplars

The aim of this study is to investigate the variability of leaf blade epidermal structures in three species of watercress, depending on abiotic factors. The practical significance lies in determining the ecological plasticity of the studied plants when grown in agrocenosis conditions. Research was conducted at the AllRussian Research Institute of Medicinal and Aromatic Plants from 2020 to 2024. The subjects of the study were young and middleaged generative plants of watercress (Lycopus europaeum), watercress (Lycopus talliana), and watercress (Lycopus splendens), derived from individuals of vegetative origin, cultivated in a field crop rotation. The experiments were established within the medicinal crop rotation system of the Agrobiology Laboratory of the Plant Growing Center through field trials. Vegetative propagation (in spring, by stolons) was used to establish experimental plantings. The study was conducted on fully formed leaf blades from the middle tier. Epidermal sections were examined on temporary preparations. The specimens were prepared using light microscopy techniques. The studied species were found to exhibit important mechanisms of physiological adaptive responses due to adjustments in morphological structure – stomata number and increased pubescence. High ecological plasticity was demonstrated for European watercress, tall watercress, and shining watercress: unlike plants growing in natural conditions, the cultivated species lack hydathodes. In drylands, under conditions of soil and atmospheric moisture deficiency, the three watercress species exhibit xeromorphic traits: an increase in the number of simple and glandular trichomes on both sides of the leaf blade, an increase in the total number of stomata, and a reduction in their size.