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1.
The structure of genotypic diversity in eight populations of the clonal triploid (2n = 3x = 36) tulip Tulipa riparia inhabiting floodplain communities in the Southern Urals was studied. Analysis of nine polymorphic enzyme systems (ADH, IDH, SkDH, PGI, PGM, FDH, NADHdh, C-EST, GOT) was performed to identify clones. Both monoclonal (D = 0) and polyclonal populations with multiple genotypes from 3 to 12 (D from 0.73 to 0.91) were identified. The polyclonal populations had a high level of heterozygosity. Dispersal of propagules (bulbs) along rivers and even from one bank of a river to the opposite was detected. Some clones disperse along riverbanks to the distance of hundreds meters (up to four kilometres). At the same time, there is an effect of “isolated” or “closed” populations. Almost each sequentially arranged population in one river system have its own set of genotypes. Assessment of the state of the reproductive system components indicates presence of a rare sexual reproduction supporting genetic diversity of T. riparia.  相似文献   

2.
Eomecon chionantha Hance, the only species in the genus Eomecon, is an angiosperm species endemic to China. Here we investigated the pollination syndrome, pollinator generalization of E. chionantha. Our results showed that the individual flower longevity of E. chionantha was 3–5 days. The flowering phenology of E. chionantha can be divided into five phases. We found significant differences in the pollination efficiency of the different insects visiting E. chionantha with bees and flies being the most efficient pollinators. This, in addition to floral morphology and phenology, suggests that E. chionantha is generalized on bees and flies and possesses an outcrossing, partially self-compatible and pollinator-dependent breeding system.  相似文献   

3.
4.
In this study we investigated the size-dependent reproductive pattern of Inula racemosa and I. royleana (Asteraceae) growing at different reaches in the environs of the Kashmir Himalaya. Size effects on reproductive pattern were evaluated by determining the size-dependency of flowering probability and reproductive effort. The results showed that the probability of flowering increased significantly with the size of the plant in all populations, indicating that individuals do not flower until they reach a threshold size and considerable between-site differences were found in the slope and the intercept of the regression between plant size and flower production. In I. racemosa, populations at high altitudes had significantly lower threshold sizes for reproduction and showed sharp increase in flowering probability with plant size, compared to other populations at lower altitudes. However, no pattern in size-dependent flower production was found relative to the altitude in I. royleana, as flower production at some sites, at high altitudes, increased more steeply with plant size than at other sites. For both taxa, reproductive effort decreased allometrically as adults grew, as can be interpreted from the allometric relationship between reproductive and vegetative biomass. Further studies are required to determine whether population differentiation in size-dependent reproductive pattern is maintained by selection.  相似文献   

5.
Experimental studies of interactions between two amphipod species (Gmelinoides fasciatus and Gammarus lacustris) showed that predation is the basic mechanism accounting for their mutual exclusion in nature. Mortality from predation among similar-sized specimens of both species at an equal abundance ratio was similar (24–25% in G. lacustris and 27–30% in G. fasciatus). The displacement of G. lacustris by G. fasciatus was observed when the latter was dominant. Adult G. fasciatus and G. lacustris successfully preyed on juveniles of their competitors and did not differ significantly in daily food consumption as a percentage of body weight: 6–24% at a fresh body weight of 18–24 mg in both species. The potential for rapid population growth under new conditions contributed to the success of the invasive Baikal species G. fasciatus in displacing G. lacustris from many water bodies of Russia.  相似文献   

6.
A comparative analysis of spatial population structure in the northern red-backed vole (Clethrionomys rutilus Pall.) and large-toothed red-backed vole (Cl. rufocanus Sund.) has been performed in the middle taiga zone of the Middle Irtysh region (Omsk oblast). Populations of these species are represented by sets of territorial groups whose numbers and spatial distribution change from year to year depending on the ratio of these species in a biotope and their population density. There is no significant interspecific competition between cohabitant Cl. rutilus and Cl. rufocanus. In particular, this follows from the fact that the population density and distribution pattern of one species are independent of those of the other species. It has been found that the size of home ranges in Cl. rutilus inversely depends on its population density, with that in Cl. rufocanus remaining approximately the same at different population densities, and that the structure of the resident part of the population in both species changes during the season, as voles from neighboring habitats or dispersing voles settle in the study area.  相似文献   

7.
Gradients of Nei's genetic distances between 15 samples of Pinus sylvestris L. trees were analyzed along three submeridional transects, from Scandinavia to the Mediterranean and Transcaucasia. As a result, distinct chorogenetic differentiation was revealed between the populations of this species growing in climatically specific regions of northern and southern Europe. Considerable Nei's distances (DN = 0.045–0.056) and their gradients, combined with differences in stable phenotypic characters (the composition of monoterpenes and morphological parameters of cones) determined at the Pyrenean and Caucasian mountain borders, suggest that the P. sylvestris species structure includes two South Eurasian subspecies, the Pyrenean P. sylvestris L., ssp. iberica Svoboda and the Transcaucasian P. sylvestris L., ssp. hamata (Stev.) Fomin.  相似文献   

8.
As climate is an important driver of vegetation distribution, climate change represents an important challenge to forestry. We (1) identify prevailing bioclimatic conditions for 49 relevant forest species in Portugal and (2) assess future shifts under climate change scenarios. We compute two bioclimatic indices (aridity and thermicity) and a new composite index, at ~1 km spatial resolution, and overlap with the species’ current ranges. Locations are based on a digital inventory, while climate parameters for both recent-past (1950–2000) and future climates (2041–2060), under RCP4.5 and RCP8.5, are provided by a multi-model ensemble of climate simulations. Results for future scenarios highlight an overall warming and drying trend. Supramediterranean and mesomediterranean climates will be significantly reduced, while thermomediterranean climates will dramatically increase, from their almost absence in current conditions to an area coverage of ~54 % in 2041–2060 for RCP8.5. There is also a clear shift from hyper-humid and humid to sub-humid and from the latter to semi-arid climates (area coverage of ~13 % in 2041–2060 for RCP8.5). Lower thermomediterranean sub-humid to semi-arid zones will cover the southern half of Portugal. These projections identify the most vulnerable (e.g. Betula pubescens, Quercus pyrenaica and Castanea sativa) and the most adapted (e.g. Quercus suber, Q. rotundifolia, Ceratonia siliqua, Pinus pinea, Quercus coccifera) species in future climates. Current bioclimatic zones associated with Eucalyptus globulus and Pinus pinaster, economically relevant species, will be moderately reduced and relocated. Possible adaptation measures are discussed to improve forest resilience to climate change, while maintaining its economic and environmental benefits.  相似文献   

9.
The composition and contents of secondary metabolites in Flavocetraria lichens from Eastern Siberia were analyzed using herbarium specimens. Based on the composition of identified metabolites, three F. cucullata chemotypes and two F. nivalis chemotypes were distinguished. Distinct geographic differentiation between the F. cucullata chemotypes was revealed, probably reflecting their adaptation to environmental conditions. The content of usnic acid in F. cucullata thalli was found to correlate with the latitude of growing region. This may be regarded as evidence for a protective role of this metabolite in lichens growing at high latitudes and exposed to excess solar irradiation during the polar day.  相似文献   

10.
The accumulation of fluorine in the trunk wood and branches of Larix gmelinii growing on soils with a naturally increased fluoride content and of L. sibirica growing in a zone affected by atmospheric emissions from an aluminum plant has been studied. Based on results of in vivo and in vitro experiments, it is concluded that larch trees manifest individual differences in their response to fluorine.  相似文献   

11.
Present study was carried out to determine pollinators’ diversity and their efficiency with modular approach; foraging behaviour, number of loose pollen adhered on their body and number of pollen deposited on the stigma. The observations explicitly indicate that Megachile spp., Xylocopa tenuiscopa, Amegilla zonata and Nomia sp. were true pollinators and out of these, Megachile spp. were key pollinators of pigeonpea. Among megachilids, Megachile lanata was the most efficient pollinator. Sufficient pollination meticulously accomplished in pigeonpea by true pollinators under this agro-ecological region.  相似文献   

12.
Fifteen A. baikalensis populations growing in natural and disturbed habitats in the dark-taiga forest belt of the Western Sayan Mountains have been studied with respect to age composition, numbers, and variation and interrelation of vegetative characters and parameters of productivity. Specific features of the effect of gaps in the tree canopy on the state of A. baikalensis cenopopulations have been revealed.  相似文献   

13.
Methods of geometric morphometrics and population phenogenetics have been used to evaluate morphogenetic rearrangements in two sympatric species of Myodes voles (M. glareolus Schreb. 1780 and M. rutilus Pall. 1779) from syntopic populations recovering after exposure to local “ecological vacuum” created as a result of rodent extermination in a natural focus of hemorrhagic fever in the southern taiga subzone of the Udmurt Republic. The model used in the study simulates the situation that arises upon nonselective elimination of rodent populations and communities in spring and their subsequent recovery. Analysis of variation in the size and shape of the mandible and in a complex of 30 nonmetric cranial characters has revealed similar (parallel) and species-specific morphogenetic and epigenetic changes occurring during the recovery of local rodent community. Species-specific differences in the pattern of change in the parameter characterizing within-group morphological disparity in the mandible shape (MNND) have been revealed between the dominant species (M. glareolus) and the subdominant species competing with it for territory (M. rutilus). Different reactions of close Myodes species in the course of filling the ecological vacuum are considered as a result of reduction in the level of competition for the subdominant species and a compensatory increase of morphological disparity in the dominant species under conditions of low density and incomplete composition of the community, in accordance with Chernov’s (2005) ecological compensation principle.  相似文献   

14.
The taxonomic diversity of the Hirudinea fauna and its dependence on the ecological conditions in the Bukhtarma Reservoir (Eastern Kazakhstan) have been studied. The morphological analysis has shown that these leeches belong to two orders and three families: Rhynchobdellida (families Glossiphoniidae and Piscicolidae) and Arhynchobdellida (family Erpobdellidae). On the whole, eight leech species from five genera (Alboglossiphonia, Helobdella, Theromyzon, Piscicola, and Erpobdella) have been identified. Among them, there are three glossiphoniid species (A. heteroclite, H. stagnalis, and T. tessulatum), two species of piscicolids (Piscicola geometra and Piscicola sp.), and three species of predatory leeches (E. octoculata, E. vilnensis, and Erpobdella sp.). Possible effects of hydrochemical parameters of the aquatic environment on the species diversity have been analyzed. Correlation has been revealed between the abundance of species and the physical and chemical characteristics of the environment.  相似文献   

15.
It is shown that the basidiocarps of many wood-decomposing fungi are inhabited by taxonomically and biomorphologically various eukaryotic (Charophyta, Chlorophyta, and Ochrophyta) and prokaryotic (Cyanophyta/Cyanobacteria) algae. They represent widespread eurybiont species and do not include any specialized mycetobionts. The communities formed by them have a host preference and green algae are their basic and obligate component, while other organisms are facultative components. Basidiocarps in which mycetobionts include heterocytic cyanoprokaryotes (Anabaena sp., Calothrix parietina, Hassallia byssoidea, Nostoc commune, N. punctiforme, Nostoc sp., and Scytonema ocellatum) are capable of molecular nitrogen fixation. Its activity is 0.044–0.903 mg of C2H4/m2/h in the basidiocarps of Bjerkandera adusta, Cerrena unicolor, Gloeophyllum sepiarium, and Trametes ochracea and 0.001–0.008 mg of C2H4/m2/h in the basidiocarps of Onnia leporina, Phellinus chrysoloma, Ph. tremulae, and Trametes pubescens. Basidiocarps without algae and those inhabited only by eukaryotic algae have no nitrogenase activity.  相似文献   

16.
It was studied the tolerance of five spring pea cultivars to Bruchus pisorum based on the weevil damage and chemical composition of seeds related to pea weevil tolerance. From visibly damaged pea seeds by pea weevil was isolated the parasitoid Triaspis thoracica Curtis (Hymenoptera, Braconidae). Cultivars with a lower protein and phosphorus content had a lower level of damage. The crude protein, crude fiber and phosphorus content in damaged seeds significantly or no significantly was increased. Modus, followed Glyans had emerged as tolerant cultivars against the pea weevil. They had the lowest total damaged seed degree, loss in weight of damaged seeds, values of harmfulness coefficient and lower protein and phosphorus content.  相似文献   

17.
The linear increment of Sphagnum fuscum and S. magellanicum in ombrotrophic mires of Western Siberia has been measured during two years over a transect about 2500 km long extending from forest–steppe to forest–tundra. Along the latitudinal gradient, the increment of both species has proved to be correlated with annual average air temperature and, in S. magellanicum, also with annual precipitation. The determinants of their growth differ between the southern, central, and northern parts of the study region. At the regional level, the annual and summer precipitation plays a more important role than the average air temperature. The increment of S. fuscum in the southern part is positively correlated with the amount of precipitation and negatively correlated with summer temperature, whereas the situation in the central part is inverse. In S. magellanicum, the linear increment is directly dependent on the annual average temperature and annual and summer precipitation in the south and on the annual and summer precipitation in the north of Western Siberia. The dynamics of linear growth of both species in bog pine forests during the growing season are similar: its rate is the highest in June, when the linear increment of S. fuscum and S. magellanicum amounts to 60 and 85% of the annual total, respectively.  相似文献   

18.
Accelerated aging of Drosophila strains with impaired detoxification of free radicals (Sod) and DNA repair (mus-210) under illumination as compared to the wild type has been demonstrated. In contrast, in a strain carrying a defective homolog of mammalian gene PCNA, the life span increases under conditions of round-the-clock illumination compared to constant darkness. The first review of the possible mechanisms underlying the effect of the illumination regime on the life span is presented, with special emphasis on the roles of the disturbance of normal circadian rhythms, increase in fecundity and physical activity (metabolic rate), and the neuroendocrine control of the insulin/IGF-1 pathway.  相似文献   

19.
The effect of long-term exposure to natural excretions of the European polecat on the morphological parameters and hormonal status of adult male Campbell hamsters (Phodopus campbelli) and dwarf hamsters (Ph. sungorus) was studied. Exposure to volatile components of natural excreta of a potential predator did not have any significant effect on hamsters. The combined influence of volatile and nonvolatile components of the polecat’s excretions caused physiological stress in Ph. campbelli, while in Ph. sungorus, on the contrary, an increase in thymus weight and the plasma testosterone level was recorded.  相似文献   

20.
Molecular genetic methods (AFLP and ITS1–5.8S–ITS2 rDNA analysis) have been used to study the level and structure of genetic diversity in relict populations of the Ural endemic Gypsophila uralensis Less. in the northeast of European Russia. Intraspecific genetic differentiation is most clearly manifested between G. uralensis Less. subsp. pinegensis (Perf.) Kamelin locally endemic to the north of Europe (Arkhangelsk oblast, locus classicus) the population of G. uralensis Less. subsp. uralensis on limestone outcrops along the Shchugor River, the Subpolar Urals. The cluster of Timan populations (on limestone outcrops along the Svetlaya, Pizhma, and Myla rivers) is autonomous and genetically heterogeneous. Genetic distances between model G. uralensis s.l. populations are correlated with geographic distances. The size and abundance of relict populations show a descending gradient in the forest zone, and parameters of their genetic diversity [1] and unbiased expected heterozygosity have been found to decrease along this gradient.  相似文献   

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