ANATOMICAL MARKERS OF THE ADAPTIVE POTENTIAL OF BETA VULGARIS L.: MESOPHYLL, IDIOBLASTS, AND THE VASCULAR SYSTEM

Abstract

This study identifies the morpho-anatomical features of the leaf and storage root of Beta vulgaris L. and evaluates their association with physiological activity and tolerance to stress factors. Fully developed leaves and storage-root samples were examined. The material was fixed using the Strasburger–Flemming method (ethanol:glycerol:water = 1:1:1); sections were prepared manually and with a freezing microtome at a thickness of 10–15 µm. Microstructural observations were carried out by light microscopy; linear measurements were taken using an ocular micrometer and the data were processed statistically. The leaf exhibited pronounced tissue differentiation: the thickness of the upper epidermis was 16.3±0.4 µm and the lower epidermis 14.2±0.7 µm; palisade mesophyll thickness was 26.1±0.8 µm and spongy mesophyll thickness 38.9±1.17 µm. Idioblasts containing dark-stained intracellular inclusions were detected in the mesophyll, along with the formation of cavities associated with water conservation, which may reflect protective responses and stabilization of the plant water regime. Vascular bundles were large and well developed, supporting efficient transport within the leaf blade. In the storage root, a well-developed periderm and a 4–5-layered primary cortex were observed; parenchyma showed accumulation of reserve substances (thickness 11.5±1.6 µm). In the central region, a diarch primary xylem pattern and secondary modifications were recorded: the vascular bundle diameter reached 187.4±2.4 µm, xylem vessel diameter was 8.4±0.1 µm, and phloem element diameter was 3.1±0.5 µm. Overall, the presence of idioblasts, the development of water-storing parenchyma, and a robust vascular system are considered key anatomical traits underpinning the high adaptive potential of Beta vulgaris L.