The consequences of chronic radiation exposure of scots pine in the remote period after the chernobyl accident

Long-term observations on Scots pine populations (2003–2012) were performed in areas of Bryansk region radioactively contaminated by the Chernobyl fallout. Throughout the observation period, the frequency of cytogenetic alterations in the root meristem of germinated seeds of pine trees from radioactively contaminated test sites significantly exceeded the control level. Seeds developing under chronic radiation exposure were characterized by high interannual variation in viability. The quality of the seeds and their resistance to additional γ-irradiation showed no definite relationship with the level of radioactive contamination in the site and the radiation dose absorbed by the generative organs of Scots pine.     

Assessment of the reproductive capacity of <Emphasis Type="Italic">Pinus sylvestris</Emphasis> trees growing under conditions of chronic exposure to radionuclides of uranium and thorium series

The reproductive capacity of Scots pine (Pinus sylvestris L.) has been estimated in trees from the population growing in an area used to store tailings from uranium ore processing and radium production. Under such conditions, 12- to 15-year-old trees produce seeds of a quality inferior to that in areas with a normal background radiation level. As the weighted absorbed dose rate (at a weighting coefficient of 5) for generative organs increases from 0.002 ± 0.0003 to 0.344 ± 0.059 mGy/day, a proportional increase is observed in the proportion of empty seeds and the frequency of cytogenetic disturbances in the root meristem of seedlings, while the survival rate of seedlings decreases. The minimum absorbed dose rate leading to these changes in the pine population is 0.027 mGy/day, i.e., 12 times as high as the control value.     

Genetic polymorphism of dwarf Scots pines in the south of Central Siberia

Polymorphism of 11 enzyme systems has been studied in dwarf Scots pine trees occurring on sand dunes and crags in two populations of southern Central Siberia. High genotypic variability of dwarfs and their similarity to normal trees in basic indices of genetic diversity have been revealed. Both populations, including normal and dwarf trees, are in the Hardy-Weinberg equilibrium. The sample of dwarf trees has proved to differ from the “norm” in showing an age-related trend toward decreased heterozygosity. The observed linkage disequilibrium at some pairs of loci can be explained by unequal contributions of trees to population reproduction or by a recent bottleneck event. The populations studied are similar to other Scots pine populations from the Asian part of the species range. Increased frequencies of some rare alleles in the populations from Tuva provide evidence for the probable presence of a glacial refugium for pine in this region.     

Specific Cytogenetic Characteristics of Pinus cretaceae and Pinus sylvestris

A comparative cytogenetic study has been performed in four populations of two pine species, Pinus cretaceae Kalen. and P. sylvestris L., growing on sandy and chalky substrates in Voronezh and Belgorod oblasts. Significant differences in the parameters of mitotic and nucleolar activities, as well as the rate and spectrum of mitotic pathology, between populations of P. cretaceae and P. sylvestris and between populations of P. cretaceae growing under different conditions have been found. Populations of P. sylvestris growing on sandy and chalky substrates differ from each other in nucleolar activity. These differences may be adaptive and reflect the characteristic metabolic patterns and biological plasticity of pines growing under specific conditions.     

Bioindication-based Estimation of Technogenic Impact on <Emphasis Type="Italic">Pinus sylvestris</Emphasis> L. Populations in the Vicinity of a Radioactive Waste Storage Facility

The spectrum and frequency of cytogenetic aberrations in the reproductive (seeds) and vegetative (foliage) organs of Scotch pine (Pinus sylvestris L.) have been studied in the vicinity of the LSK Radon facility for radioactive waste storage and processing and in a 30-km zone around the Chernobyl Nuclear Power Plant. The results indicate that the pine populations of these regions are exposed to mutagenic factors. In contrast to the 30-km Chernobyl zone, the increased environmental mutagenicity in the vicinity of LSK Radon and in the center of the city of Sosnovyi Bor is mainly accounted for by chemical factors. The results of additional acute γ-irradiation have shown an increased radiation resistance of Scotch pine seeds from the LSK Radon and Sosnovyi Bor populations. Regression analysis demonstrated a significant increase in the cytogenetic aberration rate in plants from the experimental plots throughout the study period (1997–2002).__________Translated from Ekologiya, No. 4, 2005, pp. 275–285.Original Russian Text Copyright © 2005 by Geras’kin, Vasil’ev, Dikarev, Udalova, Evseeva, Dikareva, Zimin.     

Self-fertility in scots pine as a mechanism of resistance to chemical mutagens

Experiments on chemical mutagenesis have shown that the seed progeny of self-fertile Scots pine trees (generations M₁ and M₂) have increased resistance to supermutagens, since the frequency of mitotic pathologies in them has proved to be even lower than in the F₁ progeny of self-sterile trees chronically exposed to anthropogenic impact (automobile exhausts). This is evidence that the use of self-fertile forms in selective breeding for general and specific resistance holds much promise.     

Phenes of Woody Plants: Identification,Scaling, and Use in Population Studies (An Example of Pinus sylvestrisL.)

The methods of identification and scaling of phenes of forest plants are described. The phene identification consists of five stages. Specific features of studies at each stage are shown using identification of the phenes of seed color, cone color, and seed scale structure in Scotch pine (Pinus sylvestrisL.) as examples. The method of phene scaling is based on the comparison of phene frequencies in a bog and in adjacent upland populations of pine. At the boundary between the bog and dry land, the frequencies of population-level phenes change, whereas those of superpopulation-level phenes remain unchanged.     

Cytogenetic Damage of Human Somatic Cells and Weeping Birch Cells in Voronezh Districts with Different Levels of Anthropogenic Pollution

Cytogenetic parameters (the mitotic rate and the frequency of pathological mitoses) of the seed offspring of weeping birch (Betula pendula Roth.) and the frequency of micronuclei in the buccal epithelium of children living in several raions (districts) of the city of Voronezh differing in environmental conditions were studied. Judging from these parameters, the environmental situation was the worst in the Sovetskii raion. A correlation was found between the frequency of pathological mitoses in the roots of birch seedlings and the frequency of micronuclei in the buccal epithelial cells of children. This indicates that the cytogenetic monitoring data obtained in plants may be extrapolated to man.     

Bioindication of the anthropogenic effects on micropopulations of Pinus sylvestris,L. in the vicinity of a plant for the storage and processing of radioactive waste and in the Chernobyl NPP zone

Results of a comparative analysis of the frequency and spectrum of cytogenetic anomalies are presented for reproductive (seeds) and vegetative (needles) samples taken from Scotch pine (Pinus sylvestris, L.) micropopulations growing at sites with differing levels of radioactive contamination in the Chernobyl NPP 30 km zone, and at the location of a facility for the processing and storage of radioactive wastes (the 'Radon' LWPE, near the town of Sosnovy Bor in the Leningrad Region). The data obtained indicate the presence of genotoxic contaminants in the environment of the tree micropopulations. Chemical toxins make the main contribution to the environmental contamination in the Sosnovy Bor area as compared with the influence of ionising radiation in the Chernobyl 30 km zone. The higher radioresistance of seeds of Scotch pine growing on the area of the 'Radon' LWPE and in the centre of Sosnovy Bor town was revealed with acute gamma-radiation.     

Analysis of consortive relationships between the Siberian stone pine and the nutcracker in the Northern Urals

The data presented have been obtained in the course of long-term stationary quantitative studies on the annual seed reproduction dynamics of Siberian stone pine (Pinus sibirica Du Tour) stands, including the abundance of seedlings, and the local population of the nutcracker (Nucifraga caryocatactes macrorhynchos C.L. Brehm) in forests of the Northern Urals. Statistically significant consortive relationships of the nutcracker population density with the yield of Siberian stone pine seeds and of the abundance of pine seedlings with the yield of seeds and the abundance of nutcrackers over preceding years have been hrevealed for the first time and formalized mathematically.     

Rapid thermal method for early diagnosis of the physiological state of Scots pine trees

Trends in stem temperature of Scots pine trees in different life states are described. Any substantial disturbances of water flow in the roots, stem, or crown have an immediate effect on the stem temperature. This temperature shows a strong inverse correlation with the state of the tree, with the coefficient of determination ranging from 0.710 to 0.974. The method of assessing the physiological state of trees by temperature parameters allows early diagnosis of decline in the viability of conifers.     

Influence of nonsymbiotic and symbiotic parameters of underground organs on the development of aboveground organs in <Emphasis Type="Italic">Pinus sylvestris</Emphasis> seedlings

A method is described for comparing the influences of nonsymbiotic and symbiotic parameters (accounted for by the plant itself and by the plant together with ectomycorrhizal fungi, respectively) of under-ground organs on the development of aboveground organs. The method has been used to analyze 4- to 12-month Scots pine seedlings from 26 habitats. The results show that 24 to 88% (on average, 54%) of total variation in the weight of aboveground organs is dependent on specific structural features of roots and mycorrhizae, with nonsymbiotic and symbiotic parameters of underground organs accounting for 5–73% (on average, 36%) and 3–45% (on average, 18%) of this variation.     

Dynamics of growth and seed production in the Siberian stone pine: The level and pattern of variation in characters

A statistical analysis of interannual variation in a set of vegetative and generative characters over 13 years has been performed to characterize the growth and seed production dynamics of the Siberian stone pine (Pinus sibirica Du Tour) in the southeast of the forest zone in western Siberia. The results have shown that the range of fluctuations in most of vegetative characters is ordinary and their distribution is close to normal. The range of fluctuations in many generative characters is enormous (from 0 to +∞), and the distribution of their values is usually skewed, with low values being recorded several times more frequently than high values. Most variable are the proportion of abortive cones and other characters that are determined mainly in the spring of the pollination year. These characters account for a very high level of variation in the total seed production.     

Sex Structure of Scotch Pine Populations in the Dry Steppe

it has been determined that the sex structure of the population is of great importance for pine adaptation to extreme environmental conditions. As environmental conditions deteriorate, differentiation of populations with respect to sex becomes more apparent, the proportion of trees of mixed type decreases, and the number of male trees increases. A tendency toward correlation between tree habitus, needle and shoot sizes, and the sex structure of population is noted. The prevalence of male trees in populations exposed to increasing stress reflects the rearrangement of such populations aimed at the more efficient use of natural resources.     

The survival strategy of Crepis tectorum L. under conditions of chronic atmospheric pollution

The results of demographic studies on Crepis tectorum L. populations from polluted and clean habitats are presented. They show that these populations significantly differ from each other in a number of parameters, including the seasonal dynamics of seed germination, the number of generations, the time of plant transition to reproduction, and the rate of generation succession in general. These data provide evidence that populations of annual or biennial plants can employ different survival strategies when growing under conditions of pollution or its absence.     

Chromosome aberrations as indicator of technogenic impact on conifer stands

The level of chromosome aberrations at different stages of mitosis has been studied in the seed sprout meristem of four conifer species growing in the Southern Urals in areas differing in the kind and degree of industrial pollution. The results provide evidence for the adverse effect of pollution on the chromosomal machinery of these species. With respect to environmental quality assessment, the Scots pine is the most sensitive indicator species among conifers growing in the Southern Urals and analysis of chromosome aberrations in anaphase-telophase cells is most effective among the cytogenetic methods tested.     

Assessment of biological effects in <Emphasis Type="Italic">Plantago major</Emphasis> L. Seed progeny in the zone of impact from a Copper Smelter

The quality of seed progeny was studied in Plantago major from populations growing for a long time in the gradient of chemical pollution around the Karabash Copper Smelter (KCS). The results showed that the range of variation in seed germination and seedling survival rates was wider in background than in impact populations. The lowest values of growth parameters (the number of seedlings with a true leaf and root length) were recorded in the sample from the most polluted plot. Challenging exposure to toxic elements (seed germination in soils from polluted plots) was found to stimulate, to different extents, the rate of leaf formation and suppress root growth in the seedlings. It cannot be stated from these results that the adaptive potential of plants grown in the zone of impact from the KCS is altered, compared to that in other samples. Evaluation of the prooxidant and antioxidant status of seedlings from this zone revealed a decrease in superoxide dismutase and catalase activities (to 60 and 33% of background values, respectively) and an increase in peroxidase activity (to 122%). The prooxidant status of seedlings in samples from the KCS zone was found to be increased, except for the sample from the most polluted plot.     

Edge effects on pine stands in a large city

Manifestations of the edge effect on Scots pine (Pinus sylvestris L.) trees and stands were evaluated in natural southern taiga forests growing in a large industrial city (Yekaterinburg, Russia). For this purpose, 14 transects were laid out, each consisting of 6–10 circular 400-m² plots arranged in a line that extended for 140–260 m into the tree stand, perpendicular to its boundary. During transect surveys, 128 records were made of parameters characterizing the state of pine trees (height, diameter, defoliation level, needle age) and stands (density and timber volume). The boundaries differed in age, i.e., the time of formation (no more than 8 years and more than 20 years ago), and type (adjoining to motorways or wastelands). The edge effect manifested itself only near old boundaries and only for tree height (5 m lower near the boundary than deep in the forest) and for stand density and timber volume (25% lower), independently of the boundary type. Since the test parameters linearly increased with distance from the boundary, it was impossible to estimate the range of the edge effect.     

Specific Karyological Features of Siberian Stone Pine (Pinus sibirica Du Tour) in Western Siberian Bogs

The results of a karyological study on Siberian stone pines growing in the bog demonstrated differences from the populations of this species studied earlier with respect to sizes of chromosomes and location of secondary constrictions. The number of nucleolar organizer regions in the chromosomes of Siberian stone pine trees growing in the bog was larger than in other populations. A wide spectrum of chromosome aberrations was revealed, which had not been observed in this species before. These were genome and chromosome aberrations of various types, as well as structural aberrations accompanied by changes in the number of chromosomes. It is assumed that the aberrations in the karyotype of Siberian stone pine resulted from stressful conditions.     

Analysis of sensitivity of different criteria in cytogenetic monitoring

A sensitivity scale for criteria used in cytogenetic monitoring was constructed on the basis of published data and the results of experiments on exposingZebrina pendula Schirt. plants to radon at various equivalent volume equilibrium activities. It was found that nucleolar activity and suppression of mitotic activity are the most and the least sensitive parameters in terms of response to stress, respectively.