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We studied the recovery of the growth and physiological parameters of Scots pine seedlings after long-term zinc toxicity. The removal of excess zinc from the nutrient solution resulted in the rapid recovery of primary root growth but did not promote the initiation and growth of lateral roots. The recovery of root growth was accompanied by the rapid uptake of manganese, magnesium, and copper. Despite the maximum rate of manganese uptake by the roots, the manganese content in the needles of the recovering plants did not reach control values during the 28 days of the experiment, unlike magnesium, iron, and copper. In general, the recovery of ion homeostasis eliminated all of the negative effects on the photosynthetic pigment content in the needles. However, these changes, along with recovery of the water content in the needles, were not accompanied by an increase in the weight gain of the recovering seedlings compared with that of the Zn-stressed seedlings. The increased accumulation of phenolic compounds in the needles persisted for a long period after excess zinc was removed from the nutrient solution. The decreased lignin content in the roots and needles is a characteristic feature of Zn-stressed plants. Moreover, the removal of excess zinc from the nutrient solution did not lead to an increase in the lignin content in the organs.

Abstract Forests dominate the landscape at high latitudes in the boreal regions and contribute significantly to the global carbon stock. Large areas are protected and provide possibilities to analyze natural forest dynamics including resilience to climate change. In Fennoscandia, Scots pine (Pinus sylvestris L.) and downy birch (Betula pubescens Ehrh.) often coexist in natural forests close to the limits of their ecological ranges. Tree growth in these forests is generally thought to be limited by temperature, and changes in growth trends can therefore serve as early indicators of the impact of global warming on natural ecosystems. We sampled 592 Scots pine and downy birch trees along two elevational gradients spanning the transition from the forest zone to the coniferous treeline in Tjeggelvas nature reserve, northern Sweden. Based on the tree‐ring data, we compared annual basal area increment (BAI) trends from 1902 to 2021, analyzed the ring‐width indices (RWI) in relation to local climate data, and investigated trends in climate–growth relationships. We found that the mean annual growth of both species was higher in more recent years than at the beginning of the 20th century. The RWI were positively correlated with summer temperatures, however, we found a much stronger relationship for Scots pine than downy birch. We noticed a decrease in the importance of summer temperature for Scots pine growth, whereas the importance of late spring temperatures increased over the 120‐year‐long study period. Due to strongly positive BAI trends combined with a decrease in temperature sensitivity, the overall conclusion of our study is that the influence of increasing temperatures is still positive and outweighs the negative impacts of climate change on Scots pine growth in natural forests in northern Sweden, particularly at higher elevations. Natural forests are important natural experiments that contrast the managed forests and are key to understanding the latter.

Background and Aims: Secondary plant metabolites, including organic acids and phenolic compounds, have a significant impact on the properties of organic matter in soil, influencing its structure and function. How the production of these compounds in foliage that falls to the forest floor as litterfall varies across tree age and seasonality are of considerable interest for advancing our understanding of organic matter dynamics. Methods: Monthly, we collected fallen needles of Scots pine (Pinus sylvestris L.) across stands of five different age classes (20, 40, 60, 80, and 100 years) for one year and measured the organic acids and phenolic compounds. Results: Seven low-molecular-weight organic acids and thirteen phenolic compounds were detected in the litterfall. No differences were observed across stand age. Significant seasonal differences were detected. Most compounds peaked during litterfall in the growing season. Succinic acid was the most prevalent organic acid in the litterfall, comprising 78% of total organic acids (351.27 ± 34.27 µg g− 1), and was 1.5 to 11.0 times greater in the summer than all other seasons. Sinapic acid was the most prevalent phenolic compound in the litterfall (42.15 µg g− 1), representing 11% of the total phenolic compounds, and was 39.8 times greater in spring and summer compared to autumn and winter. Growing season peaks in needle concentrations were observed for all thirteen phenolic compounds and two organic acids (lactic, succinic). Citric acid exhibited a definitive peak in late winter into early spring. Conclusions: Our results highlight the seasonal dynamics of the composition of secondary plant metabolites in litterfall, which is most different at the onset of the growing season. Fresh inputs of litterfall at this time of emerging biological activity likely have seasonal impacts on soil’s organic matter composition as well.

The aim of this study was to investigate the effect of light quality (white fluorescent light, WFL, containing UV components), red light (RL, 660 nm), blue light (BL, 450 nm), and white LED light (WL, 450 + 580 nm) on the components of the cellular antioxidant system in Pinus sylvestris L. in needles, roots, and hypocotyls, focusing on the accumulation of key secondary metabolites and the expression of related genes. The qualitative and quantitative composition of carotenoids; the content of the main photosynthetic pigments, phenolic compounds, flavonoids (catechins, proanthocyanidins, anthocyanins), ascorbate, and glutathione; the activity of the main antioxidant enzymes; the content of hydrogen peroxide; and the intensity of lipid peroxidation (MDA and 4-HNE contents) were determined. RL resulted in an increase in the content of hydrogen peroxide and 4-HNE, as well as the total fraction of flavonoids in the needles. It also enhanced the expression of several PR (pathogen-related) genes compared to BL and WL. WFL increased the content of phenols, including flavonoids, and enhanced the overall activity of low-molecular antioxidants in needles and hypocotyls. BL increased the content of ascorbate and glutathione, including reduced glutathione, in the needles and simultaneously decreased the activity of peroxidases. Thus, by modifying the light quality, it is possible to regulate the accumulation of secondary metabolites in pine roots and needles, thereby influencing their resistance to various biotic and abiotic stressors.

Somatic embryogenesis (SE) is an advanced vegetative propagation technology that, when used in combination with breeding and cryopreservation, offers the forest industry a powerful tool for the deployment of elite genotypes. Germination and acclimatization are critical and cost-intensive phases in the production of somatic plants. The efficient conversion of somatic embryos into robust plants is a necessity if a propagation protocol is to be successfully adopted by the industry. In this work, these late phases of the SE protocol of two pine species were investigated. A shortened germination protocol and more controlled acclimatization were investigated for Pinus radiata, testing embryos from 18 embryogenic cell lines. A more simplified protocol, including a cold storage phase, was also compared among 10 of these cell lines. A shortened germination period and more controlled protocols significantly improved the acclimatization of somatic embryos directly from the lab to the glasshouse. When results for all cell lines were pooled, there were significant improvements in all growth characteristics (shoot height, root length, root collar diameter, and root quadrant score). When the more simplified protocol involving cold storage was tested, improvements were seen in the root architecture. For Pinus sylvestris, the late phases of somatic embryogenesis were investigated on seven cell lines in a set of two trials (four to seven cell lines per trial). During the germination phase, a shortened and simplified in vitro period, a cold storage option and basal media were explored. Viable plants were obtained from all treatments. However, there is still the need to improve germination and related protocols together with growing regimes for Pinus sylvestris. The improvements to protocols presented here, particularly for Pinus radiata, result in greater survival and quality of somatic emblings, leading to reduced costs and increased confidence in the technology. Simplified protocols using a cold storage option show great promise and, with some further research, could lead to reductions in the cost of the technology.

Tree-ring chronologies provide high-resolution late Quaternary palaeoclimatic data. An important aim of tree-ring research is to extend the chronologies back in time, before the period covered by old living trees. Tree-ring material from historic buildings offers an opportunity to develop long chronologies that, in some regions, may cover the period of the past millennium. Such materials have remained in conditions favourable to preservation and can be used to date the construction timber by means of dendrochronology. Apart from dating, tree-ring data may prove valuable in interpreting past climatic conditions. Here we analyse the data of 111 Scots pine (Pinus sylvestris L.) tree-ring series from the Åland Islands in south-western Finland. In so doing, we illustrate the variation of wetness and drought in the region over a historical time frame (1057–1826). Non-climatic trends were removed from these series using alternative types of detrending procedures. Tree-ring chronologies constructed from the same raw data but using different types of detrending methods agreed on annual to subcentennial scales. The chronologies produced using regional curve standardization (RCS), preferably combined with implementation of a signal-free approach, were comparable with previously published sedimentary and tree-ring evidence from the same region. While non-RCS methods are effective in removing non-climatic information from the chronology, they also resulted in removal of the long-term variation (low-frequency), which did, at least in our data, represent the palaeoclimatic signal common to different types of proxy records. These records, including our data and those of gridded reconstructions developed previously as the Old World Drought Atlas, agreed in indicating dry conditions over the pre-1250 period and around the mid-15th century. The Åland chronology is characterized by notable fluctuations in the availability of tree-ring samples; the periods with low sample replication probably pinpoint years when large construction projects were suspended on these islands.

The deterioration of plant mineral nutrition during drought is a significant factor in the negative influence of drought on plant performance. We aimed to study the effects of seasonal and multiyear water shortages on nutrient supply and demand in Scots pine and Norway spruce. We studied pine and spruce trees naturally grown in the Bryansk region (Russia). The dynamics of several nutrients (K, Ca, Mg, P, Fe, Mn, Zn, and Ca) in wood, needles, and bark of current-year twigs and the dynamics of the available pools of these elements at different soil depths were analysed. To assess the physiological consequences of changes in element concentrations, lipid peroxidation products and photosynthetic pigments were measured in the needles. Water shortage increased the wood concentrations of all elements except for Mn. In pine, this increase was mainly due to seasonal water deficit, whereas in spruce, multiyear differences in water supply were more important. This increased availability of nutrients was not observed in soil-based analyses. In needles, quite similar patterns of changes were found between species, with Mg increasing almost twofold and Fe and Mn decreasing under water shortage, whereas the remainder of the elements did not change much under differing water supplies. Neither the concentrations of photosynthetic pigments nor the contents of lipid peroxidation products correlated with element dynamics in needles. In summary, water shortage increased the availability of all elements except Mn for the plant; however, needle element contents were regulated independently of element availability for plants.

In boreal forests, autumn frost tolerance in seedlings is a critical fitness component because it determines survival rates during regeneration. To understand the forces that drive local adaptation in this trait, we conducted freezing tests in a common garden setting for 54 Pinus sylvestris (Scots pine) populations (>5000 seedlings) collected across Scandinavia into western Russia, and genotyped 24 of these populations (>900 seedlings) at >10 000 SNPs. Variation in cold hardiness among populations, as measured by QST, was above 80% and followed a distinct cline along latitude and longitude, demonstrating significant adaptation to climate at origin. In contrast, the genetic differentiation was very weak (mean FST 0.37%). Despite even allele frequency distribution in the vast majority of SNPs among all populations, a few rare alleles appeared at very high or at fixation in marginal populations restricted to northwestern Fennoscandia. Genotype–environment associations showed that climate variables explained 2.9% of the genetic differentiation, while genotype–phenotype associations revealed a high marker-estimated heritability of frost hardiness of 0.56, but identified no major loci. Very extensive gene flow, strong local adaptation, and signals of complex demographic history across markers are interesting topics of forthcoming studies on this species to better clarify signatures of selection and demography.

Pinus sylvestris L. f. serpentina L. V. Orlova & V. V. Byalt var. nova (Pinaceae) – a new form of Scots pine with very specific long serpentine winding lateral shoots – was founded in the Udelnyi park (St. Petersburg) and described. Information on the location, the difference between a new form and close taxa (Latin diagnosis is given), the type specimens and their storage sites are indicated. The article is illustrated by three photos of this form in nature, a the photo of the holotype stored in LE, and a the map.

Objective – to investigate the influence of drought on allelopathic activity of Pinus sylvestris L. plants in conditions of M.M. Gryshko National Botanical Garden of the NAS of Ukraine. Material and methods. The choice of study objects was due to their habitat: plants of P. sylvestris grew in compliance with the necessary agricultural technology including regular irrigation at site 1 (control) and in the conditions of drought at site 2 that models natural ecosystems (experiment). The allelopathic activity of leaves and soil was determined. In the model experiments, Lepidium sativum L. ‘Azhur’, Triticum aestivum L. ‘Poliska 90’, Amaranthus caudatum L. ‘Rothschwanz’ were applied as the test plants. Results of the current study revealed that the allelopathic potential of needles and rhizosphere soil of P. sylvestris depends not only from the species but also from drought conditions. The inhibitory effect was stronger against root elongation than shoot elongation of seedlings. Conclusion. This study provides a laboratory-based evidence of the allelopathic effect of P. sylvestris exudates under drought stress on model plants. Studies showed that plants grown under conditions of lower soil moisture exhibit stronger inhibitory effect or slightly stimulate the growth of test objects in comparison with plants that had better water supply. This testifies to the relationship between soil moisture and seasonal allelopathic activity of the plants.

The sharing of species of ectomycorrhizal fungi (EMF) among different co-occurring host plant species could allow the formation of common mycorrhizal networks, which can alter plant–plant interactions and succession. Such sharing of EMF among woody species is thought to be common in many forests, but very few herbaceous plants form EMF, so they are assumed to be excluded from EMF networks in forests. We studied the EMF on roots of a common coniferous tree, Pinus sylvestris, and a co-occurring rare herbaceous perennial plant, Pulsatilla patens (Ranunculaceae), in northeastern Poland. We examined roots from co-occuring P. sylvestris and P. patens, visually classified EMF into morphotypes, studied tissue sections of mycorrhizal structures using compound microscopy, and used DNA sequencing to identify the fungi. On both host plant species, we observed EMF colonization, with colonized root tips exhibiting a swollen appearance, as well as a variety of colors and textures of fungal mycelium covering and emanating from those swollen tips. Sectioning and microscopic examination of an EMF morphotype common on P. patens confirmed the presence of a mantle and Hartig net, indicating the likely presence of functional ectomycorrhizal structures. The two most frequent EMF were Cenococcum geophilum and Piloderma olivaceum, and the latter was found to associate with both host plant species. Several EMF found here only on P. patens, including C. geophilum and two Russula species, are known from previous studies to also associate with P. sylvestris and other tree species. The observation of shared EMF between a coniferous tree and an understory herb indicates the potential for common mycorrhizal networks to alter interactions between these two species and may also indicate a unique way in which the distribution and abundance of a rare herbaceous plant may be influenced by shared mutualisms with a common co-occurring woody plant.

The work of this laboratory for many years with Scots pine seedlings has allowed to collect quite unique information as to the accumulation and distribution of dry matter and the reaction of plants to various environmental influences. It seems worthwhile to publish the main experimental data almost in extenso because they may be used in future work for building mathematical models of plant growth. The presented experimental data enabled to discuss controversial points of quantitative analysis of plant growth such as: the time instant and the initial value of growth to be taken as the starting points (t0 W0); exponential approximation of the growth curve; inadequacy of allometric approach in modelling vegetative growth of plants, etc. The discussion aims at defining more closely the essential notions of growth analysis.

PCR-RFLP technique has been used to detect species-specific mutations of organelles DNA for closely related dwarf mountain pine (Pinus mugo) and Scots pine (P. sylvestris). Restriction fragment patterns have been compared of amplification products for trnL-trnF cpDNA and for coxI and orf25 genes of mtDNA. The difference has been found in the Dral and Hinfl restriction patterns of the amplification products for trnL-trnF region of cpDNA with two haplotypes detected. The haplotype M is characteristic for P. mugo and the haplotype S for P. sylvestris. These markers may be useful for the analysis of the natural hybridisation and introgression between these species postulated for some sympatric populations on the basis of morphological analysis. No differences have been disclosed in the studied mtDNA regions.

Ten isolates of the ectomycorrhizal fungus Suillus luteus have been cultured on an aluminium containing growth medium in order to determine their in vitro aluminium tolerance. Five isolates originated from a site heavily polluted by acid rain with a high availability of aluminium in the soil. Five others were collected from a site free from direct pollution. Aluminium content in the sporocarps of S. luteus differed according to the site of origin and did not reveal symptoms of bioconcentration, although such phenomena were found when mycelium isolated from the sporocarps was submited to 100 mg/L Al in liquid culture. A clear relationship between Al accumulation in vitro and the site of origin of the isolate was not observed, although the highest amount of Al was found in the mycelium derived from the polluted soil. In a second experiment all isolates were grown in agar media containing 10, 100, 500 and 1000 mg/L-1 Al and the colony diameter during culture and the final colony dry weight determined. S. luteus appeared to be very tolerant to the presence of Al in the medium. Each of the parameters used to measure the metal tolerance of the fungus ranked the isolates in a slightly different order, but those originating from the polluted area showed some superiority over the others. In polluted soils this species seems to have been submitted to a selection for higher aluminium tolerance. The results are discussed with reference to the possibilities of transformating in vitro studies to situation in the forest ecosystem.

The comparison of the genetic stucture of the population of Scots pine from Szczeliniec Wielki Mt. with the population of its progeny and three other populations from the same geographic region shows great similarity of both populations as far as the frequencies of genes and genotypes are concerned. Also other genetic parameters, such as heterozygosity, genotypic polymorphism indices and a number of alleles per locus were in both populations very similar. It seems that our data proved that the provenance trial experiments reflect rather closely the genetic structure of maternal populations. The fact that the population from Szczeliniec Wielki and its "replica" are genetically most similar to the geographically closest population from Bystrzyca Kłodzka leads to the conclusion, that these populations are of common origin. Though the relic character of the population from Szczeliniec can not be excluded. The morphological distinctness of the population from Szczeliniec is caused by a modifying influence of environmental conditions.

Isoenzymatic variation of Pinus sylvestris was analysed in populations from a provenance trial (IUFRO 1982) in Kórnik and their replication in Luboń. The two groups of populations originated from the same seed pool, but the one in Luboń was exposed to pollutants emitted during the production of nitrogen-phosphorus fertilizers, while the Kórnik provenance trial were used as a control group. The parameters determining the genetic structure of the studied populations - frequency of alleles and genotypes (average number of alleles and genotypes per locus), observed heterozygosity (Ho), and genotypic polymorphism index (Pg) - have higher values in the group of trees tolerant to pollution. Also fixation index (F), which indicates that homozygotic genotypes underwent selection in this group, as well as dendrites and dendrograms according to Nei and Hedrick, suggest that the genetic structure of the populations exposed to pollution was changed. The obtained results indicate that populations characterized by a greater genetic diversity are more tolerant to pollution.

Mycorrhizal and control seedlings of Scots pine (Pinus sylvestris L.) were grown under axenic conditions at various concentrations of nitrogen (0.17 mM, 3.78 mM, 18.92 mM) and phosphorus (0.25 mM, 5.58 mM, 23.5 mM). Enzyme activities of soluble acid phosphatase of excised roots (surface-accessible activity) and of crude enzyme preparations of root tissue (total soluble activity) were analyzed in control and mycorrhizal seedlings. The content of P in pine shoot was also measured. The intermediate supply of nitrogen and phosphorus (N = 3.78 mM, P= 5.58 mM) was optimal for development of ectomycorrhizae. Activity of acid phosphatase was stimulated by higher levels of N in the soil and was higher in mycorrhizal than non-mycorrhizal roots. Pine roots had greater acid phosphatase activity at the reduced than at the higher P concentrations. The presence of mycorrhizae increased the activities of both surface-accessible and total soluble enzyme activities at lower P supply (0.25 mM, 5.58 mM) and decreased it significantly at the highest P concentration (23.5 mM). P content in shoots was higher in mycorrhizal than non-mycorrhizal seedlings.

Pinus sylvestris L. seedlings representing half-sib families of several trees of known resistance in field conditions were inoculated with three strains of Heterobasidion annosum (Fr.) Bref. representing the P intersterility group. Standardized inoculation procedure and uniform in vitro conditions allowed for evaluation of the genetically controlled host/pathogen interactions. Early and advanced stages of infection after prolonged exposure to the fungus were studied with the help of light and transmission electron microscopy. Abundance of osmiophilic material in vacuoles, necrotic reaction of cortical cells and secondary thickenings of cell walls in root regions in proximity to external mycelium were responsible for transient stagnation of pathogen spread in the cortex of resistant seedlings. Immobilized and degenerating hyphae inside vacuolar deposits in cortical cells of short roots of resistant plants are indicative of elevated toxicity of the protective materials at the initial stage of infection. Structural changes of vacuolar deposits and their subsequent disappearance, which coincided with heavy colonization of cortical cells of moderately susceptible seedlings, preceded hyphal penetration into the stele within 2-6-months after inoculation. Despite severe damage to root caps, there was no further spread of the fungus into meristems of growing roots and short dormant roots. , In susceptible seedlings, lack of a hypersensitive reaction and apparently low levels of osmiophilic material resulted in quick colonization of cortical cells, breakdown of endodermis and root abortion after entering the stele.

After prolonged (3-9 weeks) hydroponic treatment of Scots pine seedlings with different concentrations (0.5-4.0 mM) of Al (AI(N03)3), the levels of pyridine nucleotides were determined in root homogenates. After 3 weeks of Al stress, a significant decrease of the anabolic reduction charge (ARC: NADPH/(NADP+ + NADPH)) and an increase of the redox status (NAD(P)H/NAD(P)+), catabolic reduction charge (CRC: NADH/(NAD+ + NADH)) and phosphorylation capacity expressed as NADP+/NAD+ ratio was found in the 4.0 mM Al treatment. After 6 weeks, Al at concentrations of 0.5 and 1.0 mM induced an enhancement of the NADH level and a reduction of NADPH level, but the redox ratios were not changed significantly. After 9 weeks treatment with Al concentrations ranging from 0.5 to 4.0 mM, decreases of the relative level of NADP+, NADPH and NADH and increases of NAD+ were found. Consequently, the CRC, NAD(P)H/NAD(P)+ and NADP+/NAD+ ratios reached a minimum and ARC a maximum as compared to previous measurements.

One hundred and seventeen individuals representing ten hybrid families from controlled crosses between Pinus montana var. rostrata and Pinus sylvestris were examined with respect to eight traits of anatomy of their two-year old needles. The biometric data obtained by measurements of anatomical traits were used to conduct multivariant statistical analyses with discriminant analysis and Mahalanobis distances as principal methods. Some of the hybrid families were similar to parental species representing the typ Montana or Sylvestris, and some less numerous intermediate forms. The results of the anatomical studies correspond to a great extent to those obtained for isoenzymes and antigene proteins (Prus-Głowacki and Stephan 1998).

Phenolic compounds distribution was studied along the length of Scots pine needles from trees in a polluted and a control site. There is no significant difference in the content of total phenols between the studied sites. There are significant differences in distribution of phenolics along the length of needles. The highest content is in the tip part of the needle and the lowest at the base. This kind of distribution suggests a role of these compounds in the processes of necroses formation. The content of phenolic compounds is positively correlated with the toxic elements - fluorine and aluminium and negatively with the macroelements - phosphorus, potassium and magnesium.

One year old pine seedlings transferred from the nursery and potted in a greenhouse were watered with nitrogen solutions of different form and concentration (urea 0.36 mM and 0.90 mM, ammonium tartrate 0.36 mM and 1.79 mM, calcium nitrate 0.36 mM, 1.79 mM and 3.58 mM). After 10 months the growth and IAA content in needles were compared. Nitrogen fertilization affected shoot growth considerably, but its effects on root growth were less pronounced. The highest shoot weight was obtained after application of ammonium tartrate in 1.79 mM concentration. The lowest concentration of urea (0.36 mM) caused the same effect, as did the most concentrated calcium nitrate solution (3.58 mM). Auxine content increased in the needles after nitrogen fertilization as compared with control. The highest accumulation of IAA was found in seedlings treated with low concentrations of urea.

Auxin was collected from the cambial region of Pinus sylvestris by applying agar strips to the cut surfaces of stem sections which comprised a single layer of 2 to 4-mm long, mainly intact fusiform cells. Sections of the agar strips were either bioassayed immediately to determine their auxin content or stored for several months at -80oC, extracted with 80% MeOH and redissolved in hot agar prior to bioassay. Auxin concentrations were determined by Went's oat coleoptile test, as described by Funke, which was modified considerably to give highly reproducible results. The modifications proved essential for good replication of results and are described in detail together with the use of the bioassay to determine changes in cambial cell polarity during ageing and senescence in P. sylvestris.

Results of experiments performed with 6-mm high stem sections of Pinus sylvestris L. confirmed the hypothesis that the fusiform cells of the cambial region respond to the arrival of indole-3-acetic-acid (IAA) at the signalling concentration in the apoplastic space around their apical ends by increasing the basipetal efflux of endogenous natural auxin. Thus, the auxin signal propagation along the stem cambial region could be a chain of reactions between the axially neighbouring cells, each capable of responding and contributing to the change of auxin concentration in the apoplast which requires only transduction of the foreign auxin signal by each of the cells to increase the basipetal efflux of their own endogenous auxin. The rate of auxin signal propagation in this system is not limited by the rate of auxin molecular transport, and if it functions in conjunction with feedback inhibition, it may produce oscillations of the auxin basipetal efflux generating supracellular auxin waves. Inhibitors of the proteinaceous auxin efflux carrier associated with the plasmalemma (NPA and TIBA), although reducing total basipetal transport of the natural auxin, did not prevent the stimulated additional efflux of this phytohormone. The studied auxin-signal transduction processes seem to be intracellular but not mediated by the Ca-calmodulin complex. The natural auxin basipetal efflux increased significantly within 45 min following the period when it had been strongly reduced by successive collections to agar receivers replaced several times at the basal ends of 6-mm high stem sections in which the intact fusiform cells of the cambial region in about 90% are arranged in only one axial row. Such exhaustion of the cellular reserve of auxin did not prevent the additional auxin basipetal efflux stimulated by the IAA apical treatment. The results may suggest an effect of the auxin signal upon the supply of newly-synthesised auxin directly to the system responsible for its basipetal efflux.

This study dealt with the species distribution and frequency of ophiostomatoid fungi associated with the bark beetle Ips typographus on Norway spruce and Scots pine in north-eastern Poland. At all locations high spruce bark beetle damage has occurred in 2002-2003. Fungi were isolated from beetles and from brood systems of trees infested by the spruce bark beetle. The ophiostomatoid fungi were represented by 13 species. A similar spectrum of ophiostomatoid fungi as that recorded from Picea abies was associated with I. typographus on Pinus sylvestris trees. The most frequent ophiostomatoid species isolated from beetles, phloem and sapwood of Norway spruce were O. bicolor and O. penicillatum. The frequency of occurrence of ophiostomatoid fungi varied significantly among the examined locations. O. bicolor was the most frequently found species on Scots pine infested by I. typographus. The potential role of ophiostomatoid fungi in the epidemiology of I. typographus is discussed. Additionally, we also recorded how the ophiostomatoid fungi associated with spruce bark beetle could grow into phloem and sapwood of Pinus sylvestris trees.

The study makes an attempt to analyse the width of annual rings, the width of the latewood zone and the proportion of the latewood within juvenile wood along trunks of Scots pine (Pinus sylvestris L.) trees and to verify the hypothesis about the heterogeneous properties of juvenile wood in a single trunk. It was found that the above-mentioned macrostructural elements of wood structure showed a curvilinear correlation with the height of measurement points along the tree trunk. As the distance from the base of trunk increased, the width of the annual ring and the width of the latewood zone decreased, while the proportion of the latewood increased. These types of changes can affect positively physical and mechanical properties of wood tissue. It can be assumed that there is a mechanism which modifies properties of juvenile wood causing axial diversification of the analysed type of wood tissue. It is probable that axial heterogeneity results in advantageous changes in the mechanics of the tree trunk.

The assemblage and abundance of fungal species associated with Hylurgops palliatus on Pinus sylvestris, were studied in Poland. Fungi were isolated from beetles of H. palliatus and their galleries collected from three populations. In total, 1832 fungal isolates, including 38 species, were obtained. The most important group of fungi were the ophiostomatoid fungi. Among the seven species of ophiostomatoid fungi isolated, Leptographium lundbergii and an unknown species of Graphium sp. code-named "W" were the dominant species. Ophiostoma minus and O. piceae were also relatively common. All ophiostomatoid species, except L. lundbergii occurred more frequently on the overwintered adults than in gallery systems. Ophiostoma minus and O. piliferum are documented here as new associates of H. palliatus.

The diversity of the natural habitats specific to Neagra Broşteni hydrographical basin have favoured installation of two different types of pine phytocoenoses. Although both of these plants communities are characteristic to acid substrata, one is specific to oligotrophic peat - bogs (Oxycocco – Sphagnetea) and the other to mountain versants presenting acidophilous soils and accentuated slopes (Vaccinio – Piceetea). These vegetal associations are presented in phytosociological tables and analysed in this paper from the bioforms, floristic elements and ecological requests perspectives.

Annual plant species were found to have several distinct classes of hexokinases which are specific for different hexoses, such as glucose, fructose and mannose. In conifers one isozyme of hexokinase could be found in genetic studies if only glucose was employed as substrate. If fructose was substituted for glucose, another isozyme zone different from the common hexokinase could be observed in zymograms of extracts from seed tissues of Norway spruce, Scots pine and silver fir. Hence these three conifer species possess at least two different hexokinases, glucokinase and fructokinase.

Pollen quality was investigated in four stands of Scots pine (Pinus sylvestris L.) and in four stands of Pinus pallasiana D. Don plantations. As ecologically safe territories we use 70-years plantation of P. pallasiana in arboretum of biosphere reserve Askania-Nova and 80-years stand of P. sylvestris in Kremenets forestry (Ternopil Region). The study has shown that pollen viability of both species in Kriviy Rih plantations was by 8 to 15 % lower compared to pollen of plants from other regions without man-made pollution. An increased (by times) number of abnormal pollen (ranging from 1.7 to 3.1 times for P. sylvestris and from 4.5 to 18.2 times for P. pallasiana) and abnormal pollen tubes at germinating (ranging from 3 to 4 times for P. sylvestris, and from 2.8 to 14.8 times for P. pallasiana) is characteristic for both species in Krivorizhzhya compared with the stands not exposed to pollution. These sensitive indicators of the pollen quality of both species can be used as an indicator for assessing environmental pollution in industrial lands.

The vital capacity of three natural populations of Pinus sylvestris L. of Kremenets hillocks and Small Polissia by vitality, age structure, density and number seed productivity, relation of the components of allele diversity inside and outside populations is investigated. It is found that the observed population is characterized by a high level of genetic variability and great stable vital capacity.