Plant Introduction

The role of silicon ions in the resistance of Typha angustifolia to reduced soil moisture

Olena Nedukha — 2026-08-23

The results of the study of the localization and content of silicon in the leaves of narrow-leaved cattail (Typha angustifolia) plants, which grew in natural conditions on the shore of the Venetian Bay (in the Kyiv area), are presented: in water and on land. To determine the localization and content of silicon in the leaves, cytochemical and ultrastructural methods were used. Leaves were taken for the study in the vegetative growth phase. The presence and localization of silicon ions were studied using a laser confocal microscope and a scanning electron microscope. The presence of silicon inclusions in the epidermal walls of cells of the convex area (above midrids), and in cells of the stomata zone (stomata, cells surrounding the stomata, and in normal epidermal cells) on the upper and lower surfaces of cattails grown in water and in terrestrial soil was detected by laser confocal microscopy. The intensity of silicon fluorescence in the cells of the adaxial epidermis was significantly higher compared to that of the abaxial epidermis. The highest silicon content was found in epidermal cells of the convex zone, above the vascular bundles, with its content in the upper epidermis being 1.3 times higher than in the same cells of the lower epidermis. It was found that the content of silicon in the epidermis of terrestrial plants was more than that in the leaves of T. angustifolia grown in water. For the first time, a significant increase in the silicon content in the leaves of terrestrial plants of this species was also detected by electron microscopy and X-ray analysis. It has been established that the cells of the adaxial epidermis, particularly those above the conducting bundles (in the convex zone) and the stomata, are the main silicon accumulators. It is assumed that such localization and increased silicon content optimize the water balance of terrestrial plants and thus increase their tolerance to soil drought. It is proposed to increase attention to the study of silicon’s role in plant adaptation to adverse changes in abiotic environmental conditions.

Rare plant species of the Caucasian flora in the herbarium of the M.M. Gryshko National Botanical Garden of the NAS of Ukraine (KWHA): representativeness and chorology

Oleksandr Shynder — 2026-09-06

The Caucasus is one of the floristically richest regions of temperate Eurasia, characterized by high endemism and an exceptional diversity of rare and threatened vascular plant species. This study aims to assess the representativeness and geographical structure of rare Caucasian plant taxa preserved in the herbarium of the M.M. Gryshko National Botanical Garden of the National Academy of Sciences of Ukraine (KWHA). The study is based on a comprehensive inventory of Caucasian plant specimens, most of which were collected during the period of intensive botanical exploration of the region by Botanical Garden expeditions led by S.S. Kharkevich in the 1950s–1970s. During the inventory, species nomenclature was critically revised in accordance with modern taxonomic concepts. Protected taxa were identified based on their inclusion in the current Red Books of the Caucasian countries and their administrative regions. Chorological analysis was carried out by assigning taxa to geographical distribution types, with particular attention to endemic elements.
The inventory revealed 534 taxon names represented by herbarium specimens, corresponding to 527 currently accepted species and subspecies from 270 genera and 89 families. These include one species of lycophytes, one species of horsetails, 17 species of ferns, 11 species of gymnosperms, and 497 angiosperm taxa. A total of 210 species and subspecies are protected in the countries of Transcaucasia, including 131 taxa listed in the Red Book of Armenia, 69 in the Red Book of Azerbaijan, and 52 in the Red Book of Georgia. In addition, 403 species and subspecies are protected in the Red Books of the North Caucasus, with the highest numbers recorded in Krasnodar Krai (189 taxa) and Stavropol Krai (161 taxa). The geographical structure of the studied taxa is dominated by Mediterranean, Anatolian–Caucasian–Iranian, and Caucasian distribution types, which together account for 66.6 % of the total. This pattern reflects the biogeographical position of the Caucasus within the Ancient Mediterranean region. Among the recorded taxa, 107 species and subspecies are endemic to the Caucasus. Based on the analysis of herbarium material, two new nomenclatural combinations at the varietal rank are proposed: Buxus sempervirens var. hyrcana (Pojark.) Shynder & Bahatska (= B. hyrcana Pojark.) and Lilium martagon var. caucasicum (Miscz.) Shynder & Bahatska (= L. martagon subsp. caucasicum Miscz.). These combinations allow a more accurate representation of the morphological and geographical differentiation of Caucasian populations of these species, which are currently not recognized as independent taxa. Overall, the study demonstrated that the KWHA herbarium is a key ex situ repository for the study of Caucasian plant diversity in Ukraine, particularly for rare and protected taxa.

Phytocoenotic conditions of ornamental woody and shrub introducents in semi-natural communities of Chernihiv’s green infrastructure

Oleksandr Lukash — 2026-09-13

The research aims to perform a comparative phytocoenotic analysis of the growth conditions of ornamental woody and shrub introducents within four semi-natural communities of Chernihiv’s green infrastructure (the Yalivshchyna, Sviate, Podusivka Forest, and Boldyn Hills tracts). The study evaluates the impact of environmental drivers, canopy closure, and understory structure on the naturalization success of alien plants, against the backdrop of the city’s total introduced dendroflora, comprising 123 species, 2 subspecies, and 79 varieties across 33 families. Based on comprehensive architectural and adaptive criteria, the spontaneous exotic complex of 49 species recorded within the analyzed semi-natural communities was differentiated into three distinct functional-ornamental categories: shade-casting structural trees, visual and seasonal accent shrubs, and textural background, barrier, and screen plants. The work relies on field surveys conducted between 2023 and 2025, involving 58 geobotanical relevés on sampling plots of 225–625 m².
For the first time, a comprehensive analysis of Chernihiv’s forest tracts was conducted at the syntaxonomic level, identifying the pathways of their anthropogenic and climatic transformation. A direct correlation was established between decreased canopy closure (down to 20–40 %, e.g., in the Yalivshchyna tract) and the intensity of naturalization of light-demanding invasive species (Prunus serotina, Acer negundo, and Amelanchier spicata). The role of nitrogen-fixing transformer species, primarily Robinia pseudoacacia, was proven to drive the replacement of native alliances (Dicrano-Pinion) with nitrophilous communities of the class Robinietea (alliance Chelidonio-Robinion). It was substantiated that current climate warming trends, characterized by climate aridization and milder winters, act as key drivers for both drought-tolerant and previously winter-susceptible introducents to bypass historical ecological barriers, accelerating their understory expansion and altering natural successional pathways. On the slopes of the Boldyn Hills tract, the structural encroachment of Caragana arborescens and Parthenocissus quinquefolia threatens rare, relict Festuco-Brometea communities, which have been reduced to an isolated patch of approximately 10 m².
The results demonstrate a profound syntaxonomic convergence between native forest (Vaccinio-Piceetea and Quercetea pubescentis) and shrub (Rhamno-Prunetea) classes and anthropogenically induced vegetation (Robinietea and Galio-Urticetea). Ornamental introducents form stable hybrid cultural phytocoenoses that gradually diminish the natural authenticity of forest massifs, culminating in the development of the ‘urban forest’ syndrome. While relict forest cores with complex vertical structures exhibit higher ecological resilience, sparse forest-park zones and highly fragmented steppe micro-refugia require urgent differentiated management strategies and targeted population regulation of invasive transformer species.

Photosynthesis peculiarities in representatives of the Euphorbiaceae Juss. family

Nataliia Levchyk — 2026-09-16

The article provides a literature analysis of the features and advantages of С₄ and CAM photosynthesis in Euphorbiaceae Juss. representatives compared to classic C₃ metabolism. It determines the prerequisites and possible stages in plants’ transition from C₃ to C₄ and CAM photosynthesis. The C₄ photosynthesis is a convergent evolutionary system that emerged independently more than 62 times. It involves anatomical and biochemical modifications of the C₃ pathway and ensures high productivity under hot, dry conditions, tolerance to insolation, and metabolic intensity, serving as a key model of adaptive evolution. Its formation stages include the accumulation of preadaptations, the formation of proto-Kranz anatomy, the emergence of C₂ photosynthesis, the adjustment of photosynthetic components, and the development of a full-fledged C₄ pathway with simultaneous suppression of C₃ metabolism.
In CAM plants, CO₂ fixation occurs at night through the carboxylation of phosphoenolpyruvate, producing C₄ acids. Meanwhile, during the day, with stomata closed, the internal CO₂ reserve is used after C₄ acids decarboxylation, which ensures temporal process segregation. The C₂ photosynthesis type is considered an evolutionarily important intermediate stage between the classic C₃ and efficient C₄ pathways found in Euphorbia subg. Chamaesyce (i.e., Euphorbia acuta Engelm., E. angusta Engelm., and E. johnstonii Mayfield).
The Euphorbiaceae family also exhibits 'photosynthetic mosaicism', which combines different carbon fixation pathways, a phenomenon of great scientific interest and in need of in-depth study. The combination of C₃ and CAM pathways in E. tirucalli L. ensures resilience and rapid biomass accumulation, while the intermediate strategy of E. milii Des Moul. (C₃ with partial CAM cyclization) reduces water loss and illustrates the transition between C₃ and CAM. A typical tropical C₃ plant, E. umbellata (Pax) Bruyns, adapts to seasonal drought using morphological mechanisms (fleshy leaves and latex) without involving CAM. Improving crops with advanced C₄ photosynthesis can therefore increase yields of food, industrial, and energy plants and ensure efficient use of Ukraine’s plant resources.

Invasive insect pests of introduced plants of the “Olexandria” Dendrological Park. Report 5: Notes on the biology of Pineus pineoides (Cholodkovsky, 1907) (Hemiptera, Adelgidae), a pest of Norway spruce

Grigoriy Dragan — 2026-08-27

The article describes the biological characteristics of Pineus pineoides, an invasive species that entered the “Olexandria” Dendrological Park during the introduction of Norway spruce (Picea abies). Data on phenology, feeding activity, number of generations, and life cycle pattern of this pest are provided. The existence of summer diapause in the life cycle of this species is reported for the first time. A name is proposed for the morph and its variations that appear in the seasonal development cycle of P. pineoides.

80 years of the Dendropark “Olexandria” within the National Academy of Sciences of Ukraine: Ecological and coenotic research of old-growth natural oak forest and the main park-forming species of woody plants in the Dendropark “Olexandria”

Nina Dragan — 2026-10-10

This work is a concise summary of the authors’ scientific research over a 25-year period and launches a series of publications dedicated to the 80th anniversary of the “Оlexandria” State Dendrological Park (Dendropark “Olexandria”), part of the Academy of Sciences of Ukraine. The main studies focus on the park’s landscape-forming tree species – Scots pine and pedunculate oak. A number of population studies also concerned other park-forming tree species. In the Dendropark “Olexandria”, Scots pine forms the basis of most decorative compositions, while common oak retains its role as the main species in the arboretum’s natural old-growth oak forest. To date, it possesses strong edifying properties, protects the oak forest’s floristic core, and determines its ecological value. All our research was devoted to previously unexplored issues. For Scots pine, general morphogenetic reactions and their directions during adaptation to urban conditions were examined. For the first time in Ukraine, the impact of radioactive contamination on the morphogenesis of Scots pine outside the 30 km zone of the Chornobyl accident was assessed. For the oak forest, the consequences of long-term anthropogenic interference with its integrity and structure on its viability were studied. Forest pathology monitoring of the old oak forest was initiated. The initial stage included the study of the edificator species. Later, comprehensive population studies of woody plants accompanying the oak and contributing to the oak forest’s floristic core were conducted. Subsequently, similar studies of the main park-forming species were extended to non-oak areas of the Dendropark “Olexandria”. In recent years, studies of succession processes in the old-growth oak forest have been initiated, including the determination of factors, pathways, and models of oak forest degradation; the study of the possibility of its restoration or preservation; and the consequences for phytocenoses of changes in dominant species. A large part of the research was devoted to detailed examinations of the growth conditions, structural organization, and phytosanitary condition of the old-growth oak forest of the Golendernya tract, which joined the Dendropark “Olexandria” in 2008.