In petroleum-producing territories of West Siberia (Russia), oilwell gas flares have a thermal effect on nearby plant communities. Such communities can be used as models for studying plant acclimation to global warming. In the present study on the effect of the hydrothermal regime at the flare sites on mesophyll and stomatal functional traits of Betula pubescens , leaves were collected from trees at 250 m (control site [CS]), 200, 150 and 100 m (maximum impact site [MIS]) from a flare. From the CS to MIS site, the average annual air temperature increased by 0.5 °C and bog water level decreased by 17 cm. On plants from the MIS, stomata were 16% smaller and density was 20% lower compared to those at the CS, resulting in lower maximum stomatal conductance in plants from the MIS (mean ± SE: MIS 0.84 ± 0.05 mol·m −2 s −1 , CS 1.24 ± 0.06 mol·m −2 s −1 ; F = 12.6, P < 0.01). Mesophyll cell volume was 1.9 times lower at MIS than at CS. Chloroplast numbers per cell also declined with distance from the flares, from 21 (MIS) to 18 (CS; F = 15.6, P < 0.001), and chloroplast volume was 24% higher at the CS, whereas the number of mesophyll cells and chloroplasts numbers per unit leaf area were 1.9 and 1.8 times higher at the MIS than at the CS, respectively. As a result, leaves from the MIS had a large total mesophyll cell ( A mes / A ) and chloroplast ( A chl / A ) surface area per unit leaf area, resulting in a 46% increase in mesophyll conductance in plants from the MIS. Thus, structural changes in leaf epidermis consisted of a decrease in stomatal size and number, could lower transpiration losses with higher temperatures and less water. To compensate for the reduction in leaf conductance due to a decrease in stomatal conductance under these conditions, an increase in the number of mesophyll cells and chloroplasts per unit area provides a greater gas-exchange area and mesophyll conductance.

Structural and functional parameters of leaves were studied in 19 dominant and abundant species growing in shallows and wet riversides at the mouth of the Maksimikha River (Barguzinsky district, Republic of Buryatia). To evaluate the species ecological optimum Tsyganov’ scales were used (Tsyganov, 1983). To assess the resistance, the potential ecological valence of the species on the illumination scale, as well as the climatic and soil tolerance indices of the species were applied (Zhukova et al., 2010). It was shown that the index of climatic tolerance of the species was negatively correlated with the leaf mass per area (LMA) (r = -0,68) and positively with the chlorophyll photosynthetic activity of (r = 0,51). A tendency was revealed to decrease in LMA and leaf dry matter content (LDMC) and increase in the chlorophyll photosynthetic activity in more thermophilic wetland plants. Leaf area positively correlated with the scores of the species optimum on the soil moisture and acidity scales (r = 0,59 and r = 0,72, respectively). LMA, the content and photosynthetic activity of chlorophyll correlated with the optimum scores on the soil nitrogen supply scale (r = -0,53, r = -0,50 and r = 0,72, respectively). The tolerance index of the species to soil factors was associated only with the content of chlorophylls (r = 0,68) and carotenoids (r = 0,55) per unit leaf area. The potential ecological valence of the species to illumination was positively correlated with leaf density and LDMC (r = 0,58 and r = 0,57, respectively). It was concluded that the thermoclimatic optimum of species of wetland plants, as well as their climate sustainability, are associated with changes in the LMA and chlorophyll photosynthetic activity. Edaphic factors had a greater influence on the structural and functional parameters of leaves than climatic ones, which manifested in a large number of relationships between soil scales and leaf traits. Wetland plant tolerance to a wider range of edaphic conditions was associated with a high content of chlorophylls and carotenoids.

The leaf pigment complex traits of 44 wetland plant species from the Middle Urals (Russia) were studied to analyze their diversity in relation to taxonomy and life forms. The chlorophyll content per dry weight (ChlDW) and leaf area (ChlArea), the ratio of chlorophylls a and b, and CO2 uptake rates (ADW) were determined. ChlDW varied by 10-fold from 2.20 to 21.9 mg g−1 among the wetland plant species. The influence of taxonomy at the level of classes on the variation of the pigment complex traits was revealed. Dicots had greater ChlDW and had a greater proportion of chlorophylls in the light-harvesting complex (ChlLHC) than monocots. In dicots, ChlLHC was positively correlated with leaf area ratio (r = 0.63, p < 0.01), and the effect of life forms on the content and ratio of pigments was determined. In monocots, chlorophyll content was positively correlated with ADW (r = 0.75, p < 0.001) and plant height (r = 0.66, p < 0.001). In monocots, the effect of families on the pigment content was observed. The lack of differences in ChlArea between the different systematic groups and life forms indicates a similar ability of the leaf area unit to absorb a solar energy.

We studied the leaf traits of steppe species - Artemisia austriaca Jacq. (Asteraceae) and Stipa lessingiana Trin. et Rupr. (Poaceae) in two communities of true steppe and desert steppe in Kazakhstan. The whole-leaf traits changed differently within species, mesophyll traits had similar changes with aridity. The leaf thickness and the leaf mass area increased in desert steppe in Artemisia, while in grass species these leaf traits did not change. However, mesophyll cell sizes increased in desert steppe in both species. An increase in cell sizes, as well as in the chloroplast number per cell in A. austriaca and in the cell number per leaf area in S. lessingiana, led in both species to a rise of the total chloroplasts’ surface per leaf area unit being important to carbon dioxide diffusion. We concluded that despite the generally accepted stereotype about «small-cell mesophyll» in steppe xerophytes, namely in some species an increase in cell size, aimed at increasing the internal assimilation surface of the leaf, can be considered as a mechanism for adapting the photosynthetic apparatus of steppe plants to climate aridity.

The quantitative traits of the leaf mesophyll were studied for 31 steppe and forest plant species belonging to 21 families in the Altai Mountains at an altitude of 1600-2150 m above sea level. Herbaceous perennials predominated among the studied species. The studied species had an isopalisade, homogeneous and dorsoventral type of leaf meso-phyll structure. Among the species of the forest zone, the dorsoventral type of leaf structure prevailed, in the steppe zone the proportion of species with dorsoventral mesophyll is lower due to the appearance of succulents and species with an isopalisade structure of leaf mesophyll. The species of the forest belt were distinguished low leaf density by larger mesophyll cells and their low number per unit of leaf area compared to steppe plants. As a result the integral leaf mesophyll parameters of the steppe belt species - the number of chloroplasts and the total surface of chloroplasts per unit area of the leaf had higher values compared to the forest belt. It is concluded that the integral parameters of the mesophyll of the leaf strictly correspond to the conditions of species growth.

Structural and functional parameters of leaves were studied in 21 dominant and abundant species growing in shallow waters and excessively moistened banks at the mouth of the Maksimikha River (Barguzinsky district, Republic of Buryatia). The analysis of the variation coefficients revealed that in hydrophilic plants, the most variable were indicators associated with the size of the leaf blade - the area and thickness of the leaf (170 and 130 %, respectively). The parameters associated with the leaf structure, leaf density and dry matter content (DMC), depended on the degree of plant hydrophilicity. On average, the leaves of hygrophytes had denser leaves (by 41 %) with a higher DMC (by 38 %) compared to helophytes. The functional photosynthetic apparatus indicators of wetland plants, such as the content of chlorophylls per unit mass and leaf area, as well as the rate of CO2 uptake, were the most stable among the studied parameters (variation coefficients were 37, 33, and 29 %, respectively). On average, hygrophyte leaves had a 38 % lower transpiration rate and 29 % higher water use efficiency compared to helophytes. It was concluded that with a decrease in the degree of hydrophilicity of plants in the series helophytes - hygrophytes, the structural rearrangement of the leaf occurs in the direction of increasing its density and dry matter content, which is accompanied by a decrease in the transpiration rate and an increase in the water use efficiency.

Проведен сравнительный анализ параметров растений, принадлежащих к разным структурно-функциональным типам (СФТР) в степных районах Северной Евразии. Показано, что при изменении климата изменяется соотношение СФТР. С увеличением аридности климата увеличивается доля двудольных травянистых растений с изопалисаднымстроением мезофилла листа и доля С-видов, уменьшается доля растений с дорзовентральной структурой листьев. Таким образом, анализ соотношения СФТР среди степных видов растений может служить индикаторным признаком происходящих климатических изменений. A comparative analysis of the parameters of plants belonging to different structural and functional types (SFTP) in the steppe regions of Northern Eurasia is carried out. It is shown that the ratio of SFTP changes with climate change. With an increase in climate aridity, the proportion of dicotyledonous herbaceous plants with an isopalisade structure of the mesophyll of the leaf and the proportion of C-species increases, the proportion of plants with a dorsiventral leaf structure decrease. Thus, the analysis of the ratio of SFTP among steppe plant species can serve as an indicator of the ongoing climatic changes.

To identify habitat conditions, indirect ordination methods on the basis of environmental scales are used widely in Europe. However, many alien plants are absent from those scales. Bidens frondosa (Asteraceae) is an invasive alien species distributed widely in Europe. It is becoming a significant part of natural plant communities, sometimes forming monospecific stands. This study aimed to empirically determine environmental factor values using analysis of the flora accompanying B. frondosa in 22 regions of European Russia collected in a 34-year time span. In European Russia, Tsyganov environmental scales are widely used for such analyses. We determined intervals of values for each environmental factor according to Tsyganov environmental scales, namely thermoclimatic scale (TM: 7.3–9.4), climate continentality (KN: 6.0–9.4), climate aridity/humidity (OM: 6.1–8.6), cryoclimatic scale (CR: 5.3–8.8), soil moisture (HD: 9.9–17.6), scale of the soil salt regimen (TR: 5.1–10.7), soil nitrogen availability (NT: 4.4–8.5), soil pH (RC: 4.8–8.8), habitat shading (LC: 2.0–4.5), and soil-moisture variability (FH: 0.7–5.9). These data on environmental factor values can be further used in ordination analyses of plant communities where B. frondosa appears in the subzone of coniferous-deciduous forests of Eastern Europe. Results of this study demonstrate the ecological preferences of this species and can be used to determine conditions of habitats invaded by B. frondosa.

Mountain climate and vegetation change rapidly with altitude therefore many plant species may be found within a narrow elevation range. In the mountains of northern Mongolia, a relict shrub Prunus sibirica L. occurs within restricted upland areas. We studied 25 whole-plant and leaf traits of P. sibirica at 10 locations in the Khentei Mountains. A comparison with a global trait variation of terrestrial plants and a path model of apricot data measured were used to evaluate the pattern of functional response to altitude. The intraspecific variation of pigment content found in Siberian apricot was surprisingly comparable to the ranges of interspecific variation among terrestrial plants over a global scale. Increasing altitude caused a dramatic increase in both chlorophylls and chlorophyll/carotenoid ratio and a decrease in the chlorophyll a/b. We also found a decrease in leaf thickness contributed to transpiration and water use efficiency. Photosynthetic capacity and kinetics, plant sizes and biomass were not affected by altitude. The path modelling revealed that pigment content and leaf structure were two independent ways to maintain the plant carbon and water balance. Our results identify the important role of intraspecific variation in leaf pigments and structure in plant response to altitude. We propose that these leaf traits could be used as predictors for the species altitudinal limits.

Инвазионный потенциал вида определяется его физиологическими особенностями, то есть способностью вида выживать, расти и размножаться в данных условиях физической среды, а также успешно конкурировать с местными видами. Проведены исследования физиологических особенностей инвазионных видов растений в разных типах экосистем в окрестностях г. Тюмень. Изученные виды существенно различались по габитуальным и морфологическим признакам, однако, были найдены общие функциональные черты инвазионных видов, связанные с основными функциями растений, прежде всего с фотосинтезом. По сравнению с аборигенными видами той же жизненной формы и со сходными экологическими свойствами инвайдеры отличались меньшей толщиной и плотностью листа, но более высокой интенсивностью фотосинтеза. При этом инвазионные растения имели низкую эффективность использования воды. Сделано заключение, что функциональные параметры листьев могут служить индикаторами инвазионного потенциала растений. The invasive potential of a species depends on physiological peculiarities, i.e., the ability of the species to survive, grow and reproduce in the given habitat and to successfully compete with native species. We studied physiological features of invasive plant species in different ecosystems near Tyumen. The studied species differed significantly in habitus and morphology, however, we revealed common functional traits of invasive species related to the main functions of plants, primarily photosynthesis. In comparison with native species of the same life form and with similar ecological properties, the invaders were characterized by lower leaf thickness and density, but they had a higher photosynthesis rate. Invasive plants had low water use efficiency. We concluded that leaf functional traits can serve as indicators of the invasive potential of plants.

The annual weed Bidens frondosa L. (Asteraceae) has been registered for the first time in the Kurgan Region in 2020 during research on the riverine vegetation of the southwestern part of Western Siberia. This invasive species was found in ten locations along the Iset River banks in the Kurgan Region. We have postulated that the Sverdlovsk Region serves as a source for the B. frondosa invasion into the Kurgan Region along the River Iset. Despite a single short-term field survey, B. frondosa was found in several sites. In the Kurgan Region, this invasive species is characterized by low population density in all plots. Since B. frondosa populations are characterized by much higher density in other regions of European Russia, an increase in the number of locations and density of populations is expected in the Kurgan Region in the future.

The biomass allocation, leaf traits, and the CO2 assimilation rate in invasive Epilobium adenocaulon Hausskn and E. pseudorubescens A.K. Skvortsov and indigenous E. palustre L. were studied in the Middle Urals. E. adenocaulon had the maximum height, and E. palustre had the largest leaf canopy diameter. The most compact in linear sizes species E. pseudorubescens was characterized by the lowest biomass. The pattern of organ biomass allocation in invasive E. adenocaulon and E. pseudorubescens corresponded to plants with a ruderal strategy, which was expressed in a low proportion of roots and a large proportion of generative organs. Among the studied species, E. adenocaulon was characterized by the largest the stem mass ratio. The indigenous E. palustre had a large proportion of roots and leaves and a smaller proportion of generative organs, which indicated the stress-tolerant properties of this species. In addition to the pattern of biomass allocation, E. palustre differed from the invasive species in a large (30% on average) amount of chlorophyll and 1.2 times less carotenoid content, as well as low photosynthetic activity of chlorophyll. The rate of CO2 uptake per unit leaf area was the greatest in E. adenocaulon, which had thick leaves with a large leaf mass per area (LMA), exceeding that in species E. palustre and E. pseudorubescens with thin leaves with lower LMA by 1.8 and 1.6 times, respectively. A negative correlation between the CO2 assimilation rate per 1 g of dry weight and leaf density (LD) (r = –0.78, p < 0.001) predetermined the maximum value of the photosynthesis rate in E. pseudorubescens, which had the least dense leaves. The analysis of the general dataset of the functional traits indicated that the studied species of the Epilobium genus had different ecological strategies: E. palustre—S (stress tolerant), E. adenocaulon—CR (competitive-ruderal strategy), and E. pseudorubescens—R (ruderal species). It is concluded that invasive species do not have a direct negative effect on E. palustre, even being characterized by distinct ecological properties compared to native species. However, owing to the CR strategy, E. adenocaulon is able to invade riparian plant communities when they are affected by disturbing factors, which may lead to a decrease or to disappearance of the indigenous stress-tolerant species E. palustre and thus to its replacement in disturbed communities by the more competitive invasive species E. adenocaulon.

The content of chlorophylls (Сhl) a and b and carotenoids (Сar) during the growing season was studied in the leaves of 31 species of steppe and forest plants. In contrast to forest plants, steppe plants possessed less chlorophylls and carotenoids per leaf mass (2 and 1.5 times, respectively), a low Сhl/Сar ratio, a greater (1.5 times) content of carotenoids per leaf area, and a high Сhl a/b ratio. In spite of the low chlorophyll content per leaf mass in steppe plants, their content per leaf area was similar to forest species (3–4 mg/dm2) owing to their thicker and denser leaves. This suggests that the plants of steppe and forest communities have the same potential ability to intercept solar energy in this locality. In the period of active vegetation (mid-June -early August), parameters of the pigment complex were stable both in steppe and forest communities. However, steppe plants demonstrated the modified in content of Car and Сhl b, as well as Сhl/Сar and Chl a/b ratios, in the beginning and at the end of the season that indicated a reorganization of the light-harvesting complex. Intraspecific variation of parameters during the season was two or three times lower than interspecific. High interspecific variation in forest plants were achieved due to the presence of species with thick long-lived leaves. It was concluded that the chlorophyll content per leaf area reflects the adaptation of plants to climatic conditions of the geographic region, whereas pigment contents per leaf mass shows adaptation to local irradiation in plant community (forest or steppe).

The data concerning morphometric characterization of chloroplasts belonging to two groups of halophytes distinguished by their salt tolerance—“highly salt-tolerant” (Climacoptera aralocaspica L., Salicornia europaea L., and Suaeda arcuata (Bange)) and “moderately salt-tolerant” (Kochia prostrata (Schrad) L. and K. scoparia L.)—are presented. Plants of the first and second groups were grown for 2.5 months at soil salinization within limits 0–1000 and 0–600 mmol Na+/dm3, respectively. Morphometric parameters (linear sizes, proportion of stromal inclusions of starch and plastoglobules) of mesophyll chloroplasts of two groups were maintained at a constant level within corresponding range of soil salinization practically coinciding with limit of their stable photosynthetic activity. Based on these results, it is suggested that chloroplasts provide energy and assimilates to the processes of ionic and water homeostasis realized at cellular and overcellular levels within the organism’s response norm and, thereby, contribute to forming the system response of a plant to soil salinization.

Проведен сравнительный анализ параметров степных растений Западного Забайкалья и Монголии,принадлежащих к разным структурно-функциональным типам (СФТР). Показано, что растения разных СФТРразличались, прежде всего, по параметрам целого листа, таким как удельная поверхностная плотность листа(УППЛ) и объемная плотность листа (ОПЛ). Интегральные параметры мезофилла в большей степени зависели отаридности климата и не зависели от принадлежности растений к определенному СФТР.

Изучены функциональные листовые параметры у 15 видов растений ветландов в лесостепной зонеМонголии. Показано, что у прибрежно-водных растений наиболее вариабельными были показатели размера листовой пластинки (длина и площадь листа), наименее вариабельными – содержание сухого вещества (LDMC) иводы (LWC) в листе, промежуточное положение занимали сухой вес единицы площади листа (LMA), толщина иплотность листа. В среднем однодольные виды имели в 3 раза более толстые листья с большей в 11 раз площадью и в 2 раза большим LMA, чем двудольные. Сравнительный анализ листовых параметров у прибрежно-водных растений ветландов и зональных травянистых растений лесостепной зоны, показал, что интразональные изональные растения сходны по толщине листа. В то же время листья прибрежно-водных растений отличались отзональных меньшим LMA вследствие низкого содержания сухого вещества в листе, что связано с развитием аэренхимы у растений ветландов.

The peculiarities of the prevalence of C4 species in the relief of the Kyzylkum Desert were revealed based on botanical and geographical descriptions. In the lowlands (0–50 m above sea level), a predominance of C3 halophytes was found, while halophytes with C4 photosynthesis began to predominate at medium elevations (50–200 m above sea level). Above 200 m above sea level, a sharp decline in the contribution of halophilic flora to the biodiversity of native vegetation was detected. Thus, the penetration of halophytes above 200 m is limited by the presence of C4 photosynthesis as an adaptive characteristic to soil desalinization. A decrease in the succulence of leaf morphology in edificatory perennial plants of the Kyzylkum Desert (tamarix, saxaul, and camel thorn) was noted with a decrease in soil salinization. In the summer dry period, C4 photosynthesis provides a competitive advantage over C3 halophytes for survival on desalinated soils of elevated parts of the terrain desiccated during the summer. It was concluded that the acquisition of C4 photosynthesis by halophilic species is an adaptation of the photosynthesis of halophilic flora to seasonal desalinization and drying of the soil of the elevated parts of the Kyzylkum Desert.