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The effect of 1/2 LV, MSG, DCR-based nutrient media with different content of 2.4-D, BA and carbohydrate sources (maltose, sucrose) on the response of Pinus sylvestris L. megagametophytes containing immature embryos was studied. Plant material was collected from 10–40-year-old trees growing in Petrozavodsk seed orchard, progeny trial, and city park. A total number of 3260 and 1860 megagametophytes were cultivated in vitro in 2022 and 2023, respectively. Most frequently embryonal-suspensor mass formation occurred from explants collected from plus trees' clones at Petrozavodsk seed orchard and did not exceed 0.3%. The study identified a donor-tree genotype (864-2) whose explants, collected in different years, formed embryogenic cell masses proliferating for 9–10 months. It has been recommended to use the MSG nutrient medium for the successful embryonal-suspensor mass initiation. Prolonged embryonal-suspensor mass cultivation on the medium with high phytohormone content led to its degradation and required subculturing on the substrate with lower auxin and cytokinin content. In this study, we have induced the process of Pinus sylvestris somatic embryos maturation up to the clearly visible globular stage. [ABSTRACT FROM AUTHOR]

Determining the nutrient composition of woody plant roots is an important tool for studying the physiological response of trees to various environmental factors. Considering the complexity and labor intensity of collecting the roots of woody plants, especially coniferous plants, it is of particular importance to use a suitable method for the desorption of excess nutrients from the root surface to avoid the overestimation of nutrient content within the roots. In the present study, various methods for sample preparation of the roots of both Scots pine (Pinus sylvestris L.) seedlings grown in hydroculture with different aeration regimes and saplings grown in soil substrates were investigated to determine the contents of magnesium, potassium, calcium, phosphorus, iron, manganese, zinc and copper. The possibility of using root samples frozen in liquid nitrogen was also investigated. The effectiveness of different desorbing agents such as Na2-EDTA, dithionite-citrate-bicarbonate, CaCl2 and MES-Tris for nutrient removal from the root surface, as well as the duration of incubation, were studied. It was shown that desorption of nutrients from roots using EDTA is the preferred method when working with soil-grown roots. In the absence of iron-manganese plaques on the root surface, treatment of roots with DCB should not exceed 5-10 minutes to avoid ion leakage from root cells. If it is not possible to use any extraction methods, it is sufficient to mechanically remove the remaining soil particles from roots, rinse the roots with water and dry. However, this sample preparation method is not suitable for determining the iron content in roots. [ABSTRACT FROM AUTHOR]

Pinus species, used in traditional medicine and are an important industrial plant, suffer severe ecological and economic losses with the invasion of Thaumetopoea wilkinsoni (the pine processionary moth). Due to the damage caused by T. wilkinsoni, a biotic stress factor, the changes occur in the ecological and physiological parameters of Pinus species, which also try to cope with abiotic stress. The changes in fresh/dry weight, percent water content, chlorophyll a and b content, the total protein content, malondialdehyde (MDA) amounts, and superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities in leaf samples of the pine processionary moth-infested and non-infested Pinus sylvestris L. and P. nigra Arn. species were compared in the study. The leaf samples of P.nigra and P. sylvestris were collected from the Ondokuz Mayıs University Kurupelit Campus in Samsun, Turkey, in 2020. Individuals of the moth-infested and non-infested P. sylvestris and P. nigra formed two distinct experimental groups. It was found that the fresh/dry weight, percent water content, chl a and b content of the moth-infested individuals of both species were significantly decreased compared with non-infested individuals; the total protein contents, lipid peroxidation and SOD, CAT, APX activities were found to be significantly increased. It was also determined that the moth-infested individuals of both species had the most sesquiterpenes and the least monoterpenes. Our results clearly show that P. nigra and P. sylvestris defend themselves when attacked by the pine processionary moth, both by changing the amount of secondary metabolites and by reacting as antioxidative defense responses. [ABSTRACT FROM AUTHOR]

The toxic effects of lead (10 and 50 μM) in the nutrient solution and distilled water on Scots pine (Pinus sylvestris L.) seedlings were studied. It was shown that due to the rapid lead immobilization by the components of the nutrient solution, its measured concentrations were tens of times lower than the nominal ones already after 15 minutes after addition. The pronounced toxic Pb effects were manifested only on seedlings exposed to lead in distilled water, since the availability and stability of lead in such conditions were significantly higher and lasted longer than in the nutrient solution. The most pronounced toxic Pb effect was manifested in a decrease in the physiological activity of root cells and an increase in their oxidative status due to the accumulation of MDA and 4-hydroxyalkenals. Against this background, a decrease in the content of gallic acid equivalents, catechins and proanthocyanidins was noted in the roots of seedlings, while the contents of catechins and proanthocyanidins in the needles doubled. Lead exposure was also accompanied by large-scale imbalances in the contents of mineral nutrients (magnesium, calcium, potassium, iron, zinc and copper) in seedlings. It has been shown that Scots pine seedlings accumulate about 0.15 μmol/g of Pb in needles without showing any visible damage, with 0.8 μM of available lead in the nutrient solution. [ABSTRACT FROM AUTHOR]

Seasonal changes in chlorophyll (Chl) and carotenoid (Car) content were analyzed in needle samples from young Scots pines (Pinus sylvestris L.) growing in the thermal field zone at various distances from the petroleum gas flare. Experiments were performed in Khanty Mansi Autonomous Area (Yugra) of Russia throughout the autumn–winter–spring period. Two hypotheses were subject to verification: (1) the thermal field of petroleum gas combustion flame imitates the influence of climate warming on plants, thus affecting the pigment complex of the photosynthetic apparatus (PSA) in pine needles; (2) transformations of PSA pigment complex in pine needles throughout the autumn–winter–spring period are sensitive to a long-term rise in ambient temperature by 1–2°С. In the winter period, the seasonal dynamics of certain PSA parameters comprised maxima and minima that are supposedly due to the regulation of Chl and Car content upon changes in air temperature. In trees growing under divergent thermal conditions, seasonal changes of these parameters were not synchronous. Analysis of seasonal changes revealed that winter-related transformations of the PSA structural–functional condition in needles are subject to consistent variations at different distances from the gas flame. The PSA activity of needles throughout the studied period was higher near the flame and decreased with the distance from the gas flare. When Chl content in needles decreased in autumn–winter, the smallest reduction was observed in the location near the gas flare (site I) where temperature was 1–2°C higher than the background level. The intermediate decrease in pigment content was noted at a moderate distance from the flame (site III), while the most pronounced decrease occurred at the largest distance from the gas flare (site VII). At the same time, the Chl a/b content ratio in needles was consistently lower for trees located at site I than at site VII. Hence, the amount of light-harvesting complexes in chloroplasts from trees grown at site I was higher than the amount of photosystems in the same chloroplasts. The Chl (a + b)/Car ratio in needles of trees grown near the gas flare (site I) was higher than in locations III and VII. This ratio displayed two significant peaks in the winter dynamics, which was supposedly due to the sufficient preservation of green pigments. Divergent seasonal changes in Chl and Car content and their dissimilar correlations with air temperature indicate that the pools of these pigments are controlled by different mechanisms. The actual Chl content, determined by the balance of pigment degradation and synthesis, should depend on the environmentally modified Chl synthesis and on the protective function of Car. Photosynthesizing cells produce additional amounts of carotenoids during autumn–winter, thus preventing the photodegradation of Chl in the period from autumn to late spring. [ABSTRACT FROM AUTHOR]

The seasonal course of the water potential in branch xylem reflects the dynamics of photosynthetic СО2/Н2О exchange in the forest stand. Long-term figures of water potential in the branches of major wood species growing in East Siberia—larch (Larixcajanderi Mayr), pine (Pinussylvestris L.) and birch (Betulaplatyphylla Sukaczev)—have been analyzed. The seasonal dynamics of the water potential showed its minimum in the first half of the vegetation period. The time when the minimum of water potential was observed concurred with the earlier determined peak in seasonal dynamics of net ecosystem exchange (NEE) of C/СО2 in the forests of East Siberia. Statistical analysis of a long-term time series of atmospheric СО2 concentration along the latitudinal zone (43°07′–55°45′ N) of the transcontinental transect from Moscow (55°45′ N, 37°34′ E) to Vladivostok (43°07′ N, 135°54′ E) corroborated the existence of the seasonal minimum of atmospheric СО2 in the first half of the vegetation period. However, this transcontinental Eurasian minimum of atmospheric СО2 was reached a month before such a minimum in the region of East Siberia (Yakutsk, 62°05′ N, 129°33′09″ E). It was concluded that the minimum of atmospheric СО2 concentration is a seasonal signal of photosynthesis in the regional forest ecosystems, and time shift of this signal might serve as an indicator of modification in the regional biogenic cycle of carbon caused by climate fluctuation. [ABSTRACT FROM AUTHOR]

The preparative technique for water extraction of goat willow (Salix caprea L.) growing leaves was elaborated in order to stimulate Scots pine (Pinus sylvestris L.) seed germination by the extracts (patent no. 2662999). It was shown that the effects of the extract were accounted for by its biological activity, which considerably varied depending on the time of day for extract sampling. The maximal increase in gibberellin-like activity (equivalent to 3.4–3.6 µM GA3) and marked decrease in ABA-like activity (equivalent to 0.15‒0.30 µM ABA) were recorded in the willow leaf extracts harvested in the morning (8:00 a.m.) or evening (8:00 p.m.) in South Karelia (60° N) in mid-May. Application of the extracts to pine seeds afforded the maximal effects on their germination. Thus, the second-class seeds displayed qualitative characteristics of the first-class seeds (germination exceeding 80%) after the treatment. It is concluded that the introduction of the method into practice will allow utilization of the accessible, widespread plant raw material for production of the effective natural preparation, which is capable of improving sowing qualities of Scots pine seeds. [ABSTRACT FROM AUTHOR]

The composition of lipids and fatty acids (FAs) and changes in their content in needles of summer- and autumn-vegetating conifer trees growing in the cryolithozone of Yakutia have been studied by thin-layer and gas-liquid chromatography–mass spectrometry. A comparative analysis of the content of total lipids (TL) and phospholipids (PL) has been carried out, and the FA composition of TL in needles of Pinus sylvestris L. and Picea obovata Ledeb. has been determined for summer and autumn periods. In the course of adaptation to low autumn temperatures of the Yakutian cryolithozone, the TL content in needles of P. sylvestris and P. obovata significantly (by 30%) increased compared to the summer season. During this period, the phosphatidylcholine content in needles of both species also increased from 13.8 to 31 mg/g dry wt. For both species, the FA lipid composition of needles included a high content of species-specific unsaturated polymethylene-interrupted fatty acids (Δ5-UPIFA). Increase in the content of TL, PL, total FA, and Δ5-UPIFA observed during a temperature drop significantly exceeds that in plants of these species growing in other parts of Siberia. This fact is probably caused by features of low-temperature adaptation of plants in permafrost ecosystems of Yakutia. [ABSTRACT FROM AUTHOR]

Plant growth is the physiological process that is generally the most affected by drought, and growth inhibition is one of the main contributors to ecosystem productivity loss under water stress. We investigated the relationship between water homeostasis and the growth of Scots pine (Pinus sylvestris L.) seedlings under different intensities of polyethylene glycol (PEG)-induced water deficit over a period of 21 days. In culture medium water potentials from –0.15 to –1.5 MPa, we observed dose-dependent deleterious effects on seedling roots, including root growth inhibition and the depression of root cell physiological activity. One characteristic feature of severe water stress (–1.0 MPa and lower) was a drastic increase in reactive oxygen species in root cells. In contrast to root growth, needle growth was sufficiently more resistant to the decrease in needle water content. The ability to maintain the growth of the aboveground part of the seedling in conditions of water deficiency was determined primarily by the well-developed ability for cell wall adjustment. It allowed the maintenance of the turgor pressure, despite a significant drop in tissue water content, mainly due to the decrease in the osmotic volume of needle cells. We conclude that seedling growth processes, especially shoot growth, are highly resistant to water deficit, which might underlie the high competitiveness of Scots pine seedlings under the conditions of the native habitat of this species. [ABSTRACT FROM AUTHOR]

The methods of chlorophyll fluorescence induction and HPLC were used to study the influence of autumnal temperature decrease on photochemical electron-transport activity of photosystem II (PSII), nonphotochemical quenching of excessive excitation energy, and the composition of pigments in the firstyear needles of Pinus sуlvestris L. trees grown naturally in Central Yakutia. In the period from the beginning of September to October 10, the chlorophyll content was reduced by half, while the Chl a/b ratio increased from 2.9 to 4.3-4.5, indicating the degradation of peripheral antenna complexes. The decrease in average daily temperature to 4.9-6.4°C led to a transient increase in the quantum yield of nonphotochemical quenching (ΔpH-dependent parameter φNPQ). These changes were accompanied by a slow accumulation of unregulated zeaxanthin fraction insensitive to illumination conditions. The further decrease in average daily temperature to near-zero levels was paralleled by a sharp increase in zeaxanthin content, while the pH-dependent quenching was replaced with the constitutive quenching (parameter φf,D) because of the supposed structural reorganization of PSII. These processes were accompanied by a fast decrease in PSII functional activity, which was mostly due to the impairment of plastoquinone photochemical reduction. Freezing temperatures (from-3.6 to-12.1) destructed the oxygen-evolving complex in PSII and completely inactivated the PSII reaction centers. It is concluded that the largest changes in the condition of photosynthetic apparatus occur at a near-zero temperature range and proceed until complete inactivation of PSII under the action of freezing temperatures. [ABSTRACT FROM AUTHOR]

Pine (Pinus sylvestris L.) seedlings grown under controlled conditions were subjected to water deficit (external water potentials ranging from-0.15 to-1.5 MPa) by adding polyethylene glycol 6000 (PEG) to the nutrient solution. Following this treatment, the dry weights of plant shoots and roots, as well as the ratio of variable to maximum chlorophyll fluorescence (Fv/Fm), nonphotochemical quenching (NPQ) of chlorophyll excitations, photosynthetic CO2/H2O exchange, dark respiration of needles, and water potential of mesophyll apoplast in the substomatal cavity of pine needles, were measured. The imposed water deficit was followed by the inhibition of seedling growth, suppression of photosynthesis and transpiration, and by the decreased content of photosynthetic pigments. It is shown for the first time that the closure of stomata in the needles of water-stressed pine seedlings falls into the physiological reaction norm and is caused by the reduction of water potential in the mesophyll apoplast of the substomatal cavity. [ABSTRACT FROM AUTHOR]

The idea that water deficit strengthening induces concerted changes of plant physiological parameters is rather widespread. However, such changes are often difficult to identify due to challenges in establishments and maintenance of required water stress intensities using solid substrates. Therefore, we exposed Scots pine (Pinus sylvestris L.) seedlings to the range of water potentials from-0.15 to-1.5 MPa in PEG-water culture to identify the series of physiological parameters differently sensitive to water stress. We observed that even mild water stress (-0.15 MPa) inhibited root elongation, which could be one of the main pine seedlings vulnerabilities under drought. Active accumulation of osmolytes was already induced by mild water deficit and further increased with water stress severity. Plant fresh biomass growth sensitivity was more related to changes of relative water content (RWC) than to changes in tissue water content or dry weight accumulation. Plants were able to grow and accumulate dry weight down to-0.5 MPa, but lower medium water potentials (-1.0 and-1.5 MPa) suppressed growth and heavily damaged root cells, as judged from many-fold increase of Ca2+ content in roots. Chlorophyll a content was surprisingly sensitive to water stress, while carotenoids level was increased under severe stress conditions. In conclusion, the experimental system with stepwise water potential values allowed us to analyze the sensitivity scale of a range of P. sylvestris physiological processes to water stress. It was largely similar to those described earlier for other plant species, but its peculiarities were high sensitivity of root elongation, marked resistance of biomass growth to water deficit and well-developed ability to osmotic adjustment. [ABSTRACT FROM AUTHOR]

We studied seasonal changes in the content and ratio between photosynthetic pigments in one-yearold needles of Scotch pine ( Pinus sylvestris L.) growing in Central Yakutia. Maximum accumulation of chlorophylls in developed young needles occurred in July when light and temperature conditions were favorable. In this period, the needles were notable for a relatively high level of β-carotene and neoxanthin and a reduced content of lutein and the pigments of violaxanthin cycle (VXC). In the course of autumn hardening, the content of chlorophylls decreased two times. Total content of carotenoids remained the same, but pigment composition considerably changed when plants progressed from a vegetating to frost-resistant state. We revealed time and temperature ranges of variation for individual carotenoids. In the beginning of hardening at reduced and low abovezero temperatures, the content of β-carotene in the needles decreased, the pigment-protein complexes (PPC) became enriched in lutein, the pigment pool of VXC gradually increased, and the content of neoxanthin transiently rose. When average daily air temperature further decreased to near- zero values, the content of zeaxanthin sharply rose. In winter, high levels of lutein and zeaxanthin were maintained. Main changes in pigment complex of the needles of P. sylvestris were completed before the coming of steady below-zero temperatures. The obtained data suggested that, upon seasonal decrease in temperature in early stages of hardening, a decrease in the level of chlorophyll promotes a reduction in the quantity of absorbed radiant energy. Apparently, this is accompanied by activation of the role of lutein and neoxanthin that perform specific photoprotective functions in antenna PPC associated with a gradual decrease in plants' ability to quench singlet energy of excited chlorophyll. Accumulation of zeaxanthin as a result of inhibition of back reaction of epoxidation at near-zero temperatures creates necessary prerequisites for turning on the mechanisms of steady dissipation of absorbed light energy, which do not depend on transmembrane proton gradient of thylakoids. At the same time, zeaxanthin can perform antioxidant functions both in PPC and in the lipid phase of thylakoid membranes. The obtained data point to an adaptive nature of the observed reactions and a specific role of individual pigments in structural and functional reorganization of photosynthetic machinery in the course of development of frost-resistance in the needles. [ABSTRACT FROM AUTHOR]

The fatty acid (FA) composition of common pine ( Pinus sylvestris L.) needle lipids was studied. It was shown that FA composition of needle lipids changed during the entire growth period (from March to October) under the influence of environmental factors (temperature, solar radiation) affecting the biosynthesis of chloroplast membrane lipids in pine needles. Among needle lipid FAs, unsaturated polymethylene-interrupted FAs (Δ5-UPIFA) were identified: pinolenic, skiadonic, coniferonic, and other); in March and April, their content attained 16.1 and 16.9% of total FAs; it decreased in June to 6.0% and increased again in September to 20.4%. [ABSTRACT FROM AUTHOR]

Effect of mineral composition and pH of nutrient medium on the growth of Scots pine ( Pinus sylvestris L.) seedlings and their tolerance to toxic effect of zinc ions was investigated by modifying the standard Knop-Hoagland medium (pH 6.6) (M1). The improved medium (M2) was more acid (pH 4.5) and notable for 2.7-fold lower osmolarity, with equimolar ratio between ammonia and nitrate nitrogen, assimilable form of iron (9 μM Fe), and the presence of 0.02 μM Co and 2 mM Cl. Owing to balanced mineral composition and low pH, M2 enhanced seedling growth under normal conditions and reduced the toxic effect of 100 μM ZnSO. Rapid development of the root system (main root, the number and total length of lateral roots) on M2 was maintained even under stress conditions (100 μM Zn); as a result, the ratio between the biomass of aboveground organs and the biomass of the root system remained on the level of 2.5, whereas on M1, it increased to 3.9. At the same time, on M2 we observed accelerated production of the needles with elevated content of photosynthetic pigments therein. Investigation of the operation of individual components of antioxidant system (superoxide dismutase, catalase, ascorbate peroxidase, and guaiacol peroxidases) and peculiarities of proline accumulation showed that Scots pine seedlings grown on M2 experienced less oxidative stress than the seedlings grown on M1. The probable physiological foundation of the observed phenomena is discussed. [ABSTRACT FROM AUTHOR]

Functioning of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APO), and guaiacol peroxidases (GPO)) and low-molecular organic ROS scavengers (proline and phenolic compounds) in various organs (roots, cotyledons, stem, and needle) of 6-week-old seedlings of pine ( Pinus sylvestris L.) developing in the chronic presence of ZnSO (50, 100, and 150 μM). Pine seedlings were grown in water culture in the climate-controlled chamber at an irradiance of 37.6 W/m with a 16-h photoperiod, an air temperature of 23 ± 1/15 ± 1°C (day/night), and a relative humidity of 55/70% (day/night). Endogenous Zn content was a key factor determining SOD activity decomposing superoxide into HO and O. Hydrogen peroxide produced is efficiently destroyed by CAT and also by APO and GPO. At the same time, the content of proline increased (especially at 150 μM ZnSO), but the content of phenolic compounds remained unchanged. All these processes help to maintain stable intracellular levels of O and HO at elevated zinc concentrations and to prevent generation of hydroxyl radical and development of oxidative stress. [ABSTRACT FROM AUTHOR]

Physiological and biochemical features of woody plants ( Pinus sylvestris L. and Betula platyphylla Sukacz.) during transition from vegetative to frost-resistant state under conditions of extremely severe climate of Yakutia were studied. In P. sylvestris such transition was accompanied by a decrease in the content of chlorophylls long before first frosts and by an increase in the proportion of Xanth and simultaneous decrease in the content of β-carotene in needles during the first and second phases of hardening. In the period of preparation to dormancy, overwintering organs of both P. sylvestris (needles) and B. platyphylla (buds) accumulated the two groups of major dehydrins, with low mol wts of 15-21 kD and middle mol wts of 66-141 kD. Simultaneously, low temperature led to a great increase in the content of polyunsaturated fatty acids (FAs) in lipids of P. sylvestris needles and B. platyphylla buds, primarily linoleic acid and also eicosenoic FAs differing in the extent of desaturation. Observed qualitative and quantitative changes in pigments, total proteins, dehydrins, and FAs during autumn hardening of P. sylvestris and B. platyphylla plants presume their important role in the development of resistance of these tree species to low-temperature stress (down to −60°C) in the cryolithic zone of Yakutia. [ABSTRACT FROM AUTHOR]

Effects of zinc (50-150 μM ZnSO) on seed germinability, morphometric and physiological characteristics of Scots pine ( Pinus sylvestris L.) seedlings during first 6 weeks of their development were studied. Scots pine turned out to be rather sensitive to elevated zinc concentrations. This was manifested in reduced seed germinability, root system growth retardation and suppression of its development (primarily, reduction in the size of the zone of secondary root formation, their number, and total length), a disturbance in the dynamics of biomass accumulation by various organs, primarily true needles, and also the content of main photosynthetic pigments. A specificity of zinc accumulation in seedling organs was established; it depended on the degree of root system development. A competition between cotyledons and needles for essential elements was observed. It was concluded that Scots pine high sensitivity to relatively low zinc concentrations (50-150 μM) makes it a more convenient model than currently used model plants ( Arabidopsis thaliana L., Mesembryanthemum crystallinum L., Brassica napus L., and others) for studying physiological and molecular mechanisms of conifers adaptation to heavy metals and also for predictions of possible ecological consequences of environment pollution with zinc for tree phytocenoses. [ABSTRACT FROM AUTHOR]

Ophiostomatoid fungi colonize the conducting tissues of conifer stems, the phloem and the xylem. These pathogenic fungi penetrate into the stem through injuries made by xylophagous insects vectoring these pathogens. In this study the response of the phloem of Scotch pine ( Pinus sylvestris L.) to wounding (treatment 1) was compared with the response to wounding combined with application of high-molecular-weight compounds isolated from the mycelium of the ophiostomatoid fungus Ceratocystis laricicola Redfern & Minter (treatment 2). Both treatments induced the appearance of necrosis in the inner bark, the formation of periderm separating living and dead tissues, and formation of the callus alongside the wound perimeter. In addition, the bark accumulated lignin, bound proanthocyanidins, and resins, with a parallel decrease in the content of free proanthocyanidins, low-molecular-weight carbohydrates, and non-lignin components of the cell wall ( P > 0.95). The size of necrotic spots, as well as changes in the content of most substances, were significantly higher in the treatment 2 than in the treatment 1 ( P > 0.95). The accumulation of lignin in cell walls of phloem sieve cells was delayed in the treatment 2 as compared with that in the treatment 1. This suggested that the mycelial extract temporarily inhibited lignification at the early stage of the wound response. This disturbance of the cell wall protective transformation led to the hypothesis that the fungal suppressors retard the repair of inner bark injured by insects, thereby favoring the invasion of conifer tissues by ophiostomatoid fungi. [ABSTRACT FROM AUTHOR]

The time courses of CO, CH, and H2 accumulation and O2 absorption at the exposure of trunk wood samples taken from living trees of birch ( Betula pendula Roth.), bird cherry tree ( Padus avium Mill.), and pine ( Pinus sylvestris L.) in the closed volume were studied. The activity of these processes at different temperatures (from 5 to 55°C) was also examined. The main components of gas exchange in all three tree species were O absorption and CO evolution. The fluxes of these gases were equal. In experiments with dehydration-hydration of wood samples, the intrawood origin of 'woody' methane was established. Emission of CH and H from the wood depended on temperature. The temperature dependence of CH emission was similar to the temperature dependence of wood respiration. The high correlation between CO, CH, and H release and O absorption was noted. The relationships between these gas-exchange parameters were not species-specific. Temperature maxima of CH emission and the respiratory activity coincided. This implies that the highest methane emission should be expected in the period of the growth season most favorable for tree physiology. For the wood from all tree species, the ratio between released CH and CO volumes was close to 1: 160. This means that the annual methane emission from living tree is about 2 Mt C, attaining 4% of total methane emission from the territory of North Eurasia. However, taking into account a temperature dependence of methane exchange between the vegetation cover and atmosphere, we can expect that, at global climate warming, methane emission volume might be substantial. [ABSTRACT FROM AUTHOR]

The fatty acid (FA) composition of callus lipids in two pine species, Pinus sibirica Du Tour and P. sylvestris L. was studied. Callus lipids were characterized by a high content of unsaturated FAs: 81.7% in P. sibirica and 63.2% in P. sylvestris. Among them, oleic and linoleic acids predominated (22.9 and 34.0% of total FAs in P. sibirica and 17.6 and 27.8% in P. sylvestris, respectively). Callus lipids also contained Δ5-UPIFA (unsaturated polymethyle-interrupted FAs), where pinoleic and sciadonic acids predominated. A comparison of FAs in the lipids of P. sylvestris calluses derived from needle and needle photosynthesizing tissues of this pine species showed that callus lipids were characterized by a greater diversity of Δ5-UPIFA but a lower degree of FA unsaturation and he higher level of Δ5-UPIFA. [ABSTRACT FROM AUTHOR]

Changes in the levels of ascorbic acid (AA), its oxidized form, dehydroascorbic acid (DHA), and uronic acids as initial precursors for the AA synthesis were studied as related to the degree of xylem and phloem cell development in the course of early and late wood formation in the trunks of Scots pine ( Pinus sylvestris L.). The cells of mature and conducting phloem, cambial zone, differently developed cells in the zones of cell enlargement and maturation were obtained by successive scraping tissue layers from trunk segments of 20–25-year-old trees; tissue identification was checked anatomically and histochemically. The contents of compounds tested were calculated per dry weight and per cell basis. We found great differences in the contents of AA and DHA and also in their ratio in dependence of the wood type developing in the pine trunks during growth period and on the stage of differentiation of xylem and phloem cells. Changes in the AA content during xylem cell differentiation were accompanied by changes in the content of uronic acids. The amounts of AA, DHA, and uronic acids were the highest at the stage of early lignification and reduced with tracheid maturation. The AA to DHA ratio changed differently in the course of early and late xylem lignification. It reduced from the start of lignification to the formation of early mature xylem and, in contrast, increased in mature late wood; this indicates a difference in the level of redox processes in these tissues. [ABSTRACT FROM AUTHOR]

The fatty acid (FA) composition of storage lipids in the seed endosperms and embryos of two pine species, Pinus sibirica and P. sylvestris, and possible biosynthetic pathways of these acids were studied by the GLC method. Linoleic acid predominated in the embryo and endosperm lipids of both P. sibirica (43.5 and 42.6%) and P. sylvestris (44.8 and 46.8%); this was evidently determined by a high expression of the gene encoding stearoyl-Δ9 acyl-lipid desaturase and the fad2 gene encoding microsomal ω6 acyl-lipid desaturase. P. sibirica lipids of the embryo and endosperm contained more oleic acid (22.0 and 24.0%, respectively) than corresponding P. sylvestris lipids (18.7 and 14%). Storage lipids of conifer seeds contain Δ5-unsaturated FAs: taxoleic (18:2Δ5,9), ephedrenic (18:2Δ5,11), pinoleenic (18:3Δ5,9,12), skiadonic (18:3Δ5,11, 14), and coniferonic (18:4Δ5,9,12,15). In the endosperm and embryos of P. sylvestris, the content of pinolenic acid was higher (22.1 and 19.6%) than in P. sibirica seeds (19.1 and 18.6%). [ABSTRACT FROM AUTHOR]

The effect of boron availability on the content of fatty acids (FA) in the total lipids of needles was investigated in two-year-old seedlings of Scots pine ( Pinus sylvestris L.). The study was conducted in the forest nursery on the soil deficient in boron. Various rates of boric acid (0.01, 0.03, 0.1, 0.3, 1, 3, and 10 g/m2) were applied to soil three times throughout the growth period. When pine seedlings were supplied with extra boron, the lipid content of the seedling needles declined. The optimal boron supply elevated the content of saturated FA in total needle lipids mostly at the expense of palmitic acid, with a corresponding decline in the level of unsaturated FA and unsaturation index of FA owing to trienoic FA (mainly linolenic and hexadecatrienoic acids). At the same time, the level of monoenoic and to a lesser degree dienoic acids increased. When boron supply of the seedlings was not optimal, the content of unsaturated and low-molecular FA increased. [ABSTRACT FROM AUTHOR]

Ion-exchange properties of needle cell walls were studied on healthy and severely weakened Scotch pine ( Pinus sylvestris L.) trees subjected to industrial pollutions with sulfur and heavy metals. Three types of cation-exchange groups were identified: carboxylic groups of polygalacturonic acid, carboxylic groups unrelated to polygalacturonic acid, and phenolic OH-groups. The needles of impaired trees (vigor state IV) differed from needles of healthy plants (vigor state I) by a higher coefficient of cell wall swelling, higher nitrogen content, and lower content of ion-exchanging groups in the cell wall structure. It is supposed that differences in ion-exchange capacity of cell walls could be among the causes for distribution of pine trees into several groups according to their vigor. [ABSTRACT FROM AUTHOR]

The respiratory CO2 exchange and the growth of the annual shoots were followed in Scots pine ( Pinus sylvestris L.) trees growing under extreme continental forest-steppe conditions near the lake Baikal. The temperature coefficient of dark respiration (Q10) in growing shoots dropped down from 3.2–4.0 (in the temperature range of 10–20°C) to 1.5–2.0 (in the temperature range of 20–30°C). The changes in averaged daily respiration rates correlated with the changes in shoot growth increments and temperature (with the multiple determination coefficient of 0.94). Growth respiration of the axial shoots during the phenophase reached 80% of the total respiration costs, with the coefficients of growth respiration and maintenance respiration 0.32 and 0.021. In young crown shoots, the average value of CO2 evolution in the light combined for the whole observation period (years 1976–2004) was about 1 kg/dm2, that is 9% of CO2 evolution from the trunk surface. [ABSTRACT FROM AUTHOR]

An infrared gas analyzer was operated in an open-circuit differential mode to measure CO2 gas exchange in intact leafy and leafless parts of skeletal branches of Pinus sylvestris L. throughout the summer daylight period. The photosynthetic carbon sequestration in major types of forest phytocenoses in northern Eurasia was assessed for middle-aged and moderately dense stands. The estimates were corrected for carbon losses associated with phloem transport of photosynthetic products per each meter of transport pathway (14 kg C/(kg chlorophyll m)), as well as for respiratory losses of heterotrophic phytomass. A high correlation (R2 = 0.82) was found between this component of production process in the current growth season and the chlorophyll index for major forest associations of northern Eurasia. It is concluded that the transport-related carbon losses of photosynthetic products in the phloem over the current growth period (1100 h) enlarge significantly as the mean stand height increases during the tree growth and upon the regional shift from north to south. [ABSTRACT FROM AUTHOR]

Pine (Pinus sylvestris L.) callus culture was treated with the mycelium extracts from six Fusarium strains. Previously, pine seedlings were infected with a spore suspension in order to test the pathogenicity of the used strains. Callus culture infection resulted in a decrease in the free proanthocyanidin (PA) and an increase in bound PA content. After treating the calli with all strains except F. oxysporum var. orthoceras, the lignin content became lower than the control one. The most considerable changes involved the p-hydroxybenzoic acid (HBA) content, and its greatest change was observed after treating the calli with F. nivale, when the HBA concentration (1229 μg/g dry wt) exceeded fourfold the control one. There was a positive correlation (R = 0.81) between the HBA content in the callus culture cells treated with a fungal extract and the virulence of Fusarium strains. At the same time, there was an inverse correlation (R = –0.80) between the lignin content in a callus culture and the fungal virulence; the latter did not affect the contents of both free and bound PA. [ABSTRACT FROM AUTHOR]

Twelve-day-old seedlings of Scots pine (Pinus sylvestris L.) were infected with a virulent spore suspension of the fungus Fusarium sporotrichiella var. sporotrichioides Bilai. 72 h after infection, the seedlings were divided into infection-susceptible and infection-resistant ones, and phenolic compounds in the seedling hypocotyls were analyzed. Susceptible seedlings contained 4.3-fold less lignins, 1.4-fold less free and bound proanthocyanidins, 12.7-fold less free hydroxybenzoic acids, 56.6-fold less bound hydroxybenzoic acids, 2-fold less quinic acid, and 5.1-fold less shikimic acid as compared to the resistant seedlings. At the same time, L-phenylalanine content was increased 3-fold and that of L-tyrosine, 1.3-fold. The activity of quinate:NAD(P)+ oxidoreductase and L-phenylalanine ammonia-lyase in the hypocotyls of susceptible seedlings was 2.3-fold and 1.4-fold lower, respectively, whereas the activity of shikimate:NAD(P)+ oxidoreductase remained unchanged. [ABSTRACT FROM AUTHOR]

The CO2 exchange of pine (Pinus sylvestris L.) shoots was continuously monitored over several years. The spatial and temporal variability of gas exchange was thoroughly investigated for three forest types. The net uptake of CO2 by current-season shoots in a bilberry pine stand equaled 5.4 g CO2 per g dry wt for the growing season. The net CO2 assimilation by one-year-old shoots over a growing season constituted 9.9 and 2.4 g CO2/(g dry wt year) in the upper and lower crown parts, respectively. The nighttime respiration of the current-season shoots released 0.7 g CO2/(g dry wt year), and the respiration of one-year-old shoots in the upper and lower parts of the canopy released 0.45 and 0.36 g CO2/(g dry wt year), respectively. Recalculation of three-year data per entire crown yielded an annual average carbon assimilation of 1.54 g C/(g dry wt year). Water relations markedly affected CO2 fixation. Nevertheless, the daily average values of photosynthesis in the summer were similar for pine stands with bilberry, heather, and dwarf shrub–polytric as understory dominants. It is shown that the realization of changes in photosynthetic function is related in time to growth processes. [ABSTRACT FROM AUTHOR]

Morphophysiological correlations were studied in medium-aged (20- to 60-year-old) Scots pine trees under the northern taiga conditions. Under various ecological conditions, pine trees developed a well-balanced structure, with close linear relationships between needle and root weight and their cross-section areas in all components of the continuous transport network (the coefficient of determination was between 0.88 and 0.999). When the annual cycle of soluble and insoluble carbohydrate contents was followed in various pine tissues, the total concentrations of soluble and insoluble carbohydrates were maintained at constant and tissue-specific levels, except in the growth period. The maximum level of carbohydrates was observed in all tissues at the beginning of rapid growth, and the minimum, at growth cessation. The qualitative composition and amount of carbohydrates matched the phenological phases of development and were not affected by the ecological growth conditions pertinent to the particular environment. The authors conclude that assimilate synthesis and partitioning are related to structural development, and the state of sink centers determines the attracting capacity, whereas the transport network, from roots to needles, and its conducting capacity are essential for the realization of systemic relationships and the control over growth and development in Pinus sylvestris L. [ABSTRACT FROM AUTHOR]

The pigment composition and light-response curves of the indices of prompt chlorophyll fluorescence were investigated in needles sampled from various parts of the tree crown in pine trees growing under natural conditions at various distances from a source of industrial air pollution (a copper-melting works). Shading and pollution decreased the threshold light level of the state corresponding to the second phase of the light-response curve of nonphotochemical chlorophyll fluorescence quenching, increased a nonradiating dissipation of the absorbed light energy, and decreased the rate of electron transfer between PSII and PSI. The patterns thus established demonstrate the existence of nonspecific chloroplast responses to pollution and shading similar in their mechanism, which decrease the efficiency of light energy utilization. [ABSTRACT FROM AUTHOR]

CO2exchange in the leafy and skeletal parts of attached shoots of Pinus sylvestrisL. was measured with an infrared gas-analyzer in an open differential system during daylight hours. The 14CO2assimilation rates in the leafy parts of shoots and 14CO2evolution from current photosynthetic products in the lower skeletal part of shoots were measured in afternoons. Chlorophyll content was measured in the needles of the same shoot. The carbon of exported assimilates contributed only about 4% to CO2exchange in the heterotrophic tree tissues. Only this component of CO2evolution from the surface of the skeletal part of the tree was related to the losses of the net primary photosynthetic production (NPP) in the aboveground part of the pine stand during the current growth period. [ABSTRACT FROM AUTHOR]

The morphological and functional organization of the needles of Scotch pine ( Pinus sylvestris L.) and Siberian fir ( Abies sibirica Ledeb.), which differ in their light requirement were studied. The characteristic properties of the high-light-requiring pine included high rates of apparent photosynthesis and dark respiration, high assimilation number, numerous folds in mesophyll cell walls, and increased partial volume of intercellular spaces and hyaloplasm in the mesophyll. In the needles of shade-enduring fir, the higher efficiency of photosynthesis at low light intensities depended on the higher number of membranes and higher pigment content in the chloroplasts. The low assimilation number in fir indicated a shortage of photosynthetic reaction centers. The relative volume of the vascular cylinder and the vascular bundles in the needles and the partial volume of chloroplasts in the hyaloplasm, are considered as indices of the rate of assimilate export from mesophyll cells and their possible damping at different levels of structural organization. [ABSTRACT FROM AUTHOR]