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1.
The results of field studies at the Krasnosamarskii Station of Samara State University (the Samara River valley, the subzone of herb–sheep's fescue–feather grass steppes on ordinary chernozem) have shown that the age structure, ecological density, age index, and regeneration capacity of green strawberry cenopopulations depend on the trophic level and moisture content of soil and on the shading and mulching action of litter.  相似文献   

2.
This study looks into T. officinale cenopopulations growing in the Techa River floodplain under conditions of chronic low-dose irradiation. It has been shown that the left-bank and right-bank cenopopulations differ from one another, as well as from the control (background) population, in the allozyme structure, viability, and radioresistance of the seed progeny and the mechanisms of antioxidant protection. In nature, cenopopulations differing in their phenogenetic structure may have different strategies of adaptation to the chronic influence of low radiation doses against the background of changing environmental conditions. The consequences of irradiation for such cenopopulations, including the viability and radiosensitivity of their seed progenies, may also differ considerably.  相似文献   

3.
Some up-to-date methods of analysis of the spatial and age structures of populations, including local population density maps and Ripley’s functions, are described using 20 cenopopulations (CPs) of Adonis vernalis L. as an example. Pregenerative plants have been found to be the most contagious, irrespective of climatic and phytocenotic conditions and land use type. The spatial distribution pattern and structure of A. vernalis are mainly determined by generative plants forming a tussock, irrespective of the climate and vegetation type. This is explained by higher competitiveness of generative plants, which results in a reduced vegetation density at small distances from them (25–50 cm). Within wider areas, plant distribution may be random due to uniformity of local conditions in microhabitats. The formation of distinct plant aggregations is accounted for by insufficient water supply and the intensity and type of anthropogenic impact.  相似文献   

4.
A comparative study of the greater plantain seed progeny was performed with samples from cenopopulations growing for a long time under conditions of radioactive contamination (in the Eastern Ural Radioactive Trace, EURT) or chemical pollution (in the impact zone of the Nizhny Tagil Iron and Steel Works, NTMK). The progeny of plants from the NTMK zone had low viability but proved to be resistant to the additional impact of a “new” factor (acute γ-irradiation) as well as of the “habitual” factor (heavy metal toxicity). Plantain seeds from the EURT area showed high viability and low heavy metal and radiation resistance; i.e., no preadaptation effect was revealed. In experiments on growing plants from different cenopopulations in plot culture, samples from the EURT zone were characterized mainly by morphoses of generative organs, while samples from the NTMK area, by morphoses of vegetative organs.  相似文献   

5.
Specific ecogenetic features of plants and parameters of seed progeny have been studied in Melandrium album cenopopulations from test plots established along the radioactive contamination gradient in the zone of the Eastern Ural Radioactive Trace (EURT), where absorbed radiation doses in buffer and impact plots exceeded the background level by factors of 2–18 and 330–418, respectively. It has been shown that interannual variation in parameters characterizing the viability of seed progeny largely depends on fluctuations of weather conditions. This dependence is more distinct in cenopopulations from the EURT than in control samples, which is indicative of interaction between radiation and other relevant ecological factors. The radioresistance of seed progeny is contingent on its viability, being independent of radiation load at the sites of maternal plant growth. Hermaphrodite plants occur only in irradiated M. album cenopopulations. This character is inherited: all F 1 descendants of such plants grown in a vegetation experiment had hermaphrodite flowers. The mutability of seed progeny formed in the EURT zone exceeds the background level. The occurrence and frequencies of recorded anomalies has proved to vary by years and, therefore, can be interpreted as nonheritable modifications.  相似文献   

6.
The authors present the results of studies on the state of cenopopulations (demographic parameters, ontogenetic structure, ageness, self-maintenance capacity, and vitality structure) of the bulbiferous perennial Lilium monadelphum Bieb. and on the ontogenetic strategy of this rare species under stress.  相似文献   

7.
The effects of two exogenous factors, ground fires and industrial air pollution, on natural regeneration of Scots pine (Pinus sylvestris L.) cenopopulations have been studied in the Transural region. It has been found that an increased level of air pollution leads to a decrease in the abundance and occurrence frequency of pine undergrowth; as the intensity of ground fire increases, these parameters of the postfire generation of undergrowth increase as well, especially in background areas. As shown by two-way ANOVA, either of these factors and their interaction have a significant effect on the density of pine undergrowth, with this effect being stronger in the case of ground fires.  相似文献   

8.
Data are presented on the abundance, structure, and dynamics of hemipopulations of G. conopsea protocorms and autotrophic individuals at the northern boundary of the species range. The dynamics of ontogenetic structure of G. conopsea cenopopulations have a fluctuating pattern. Their response to adverse weather conditions is manifested in short-term reduction of density and increase in cenopopulation ageness in subsequent years. Deterioration of growing conditions in a series of ecotopes is accompanied by an increase in the proportion of young individuals, which allows the species to level off the impact of adverse weather factors on population size.  相似文献   

9.
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   

10.
The results of the study have shown that the stocks of 90Sr and 137Cs in the frontal part of the EURT are 6700–15000 and 200–400 kBq/m2, respectively. The coefficients of their accumulation in different herbaceous plant species in this impact zone are lower than in other areas. The accumulative capability of plants has probably decreased in the course of selection as an adaptation to the effect of radiation. The viability and growth parameters of Plantago major L. seeds from the EURT zone are similar to those of seeds from the background sample. Cenopopulations chronically exposed to radiation are characterized by a higher mutation rate in the progeny and an unstable response to additional acute irradiation in most characters studied. A high level of inbreeding is observed in all P. major cenopopulations of plantain. The cenopopulation of the impact zone is characterized by a lower variation of allozyme loci, which may be a result of stringent selection for individuals better adapted to the complex of conditions existing in its habitat.  相似文献   

11.

The ideas of the evolutionary ecology of the 20th century and its modern conceptual space are considered with regard to new knowledge of the contents of population and evolutionary synecology. The article proposes (1) a population cenotic approach to analyzing the covariation of cenopopulations of sympatric species and taxocenes in space and historical time; (2) an approach to assessing the intragroup morphological disparity in cenopopulations of sympatric species and taxocenes as a measure of morphogenetic stability. Consideration is given to experimental evolutionary ecology as a particular methodological area. Prospects for the formation of evolutionary ecology as an interdisciplinary applied science are discussed in view of the necessity of predicting regional biocenotic crises and rapid coevolutionary changes in biotic communities in a technogenic environment against the background of predicted unfavorable trends of climate changes.

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12.
Long-term studies have been performed on the seed progeny of B. inermis from test plots established along the radioactive contamination gradient in the zone of the Eastern Ural Radioactive Trace (EURT), where dose loads on maternal plants and embryos of seeds from chronically irradiated cenopopulations (with natural background radiation taken into account) exceed control values by factors of 2 to 107. Interannual and individual variation in the viability, mutability, and radiosensitivity of the seed progeny has been revealed. Against the background of high interpopulation variation in test parameters in the EURT zone, weather conditions appear to have no significant effect on seed quality, while such effects are appreciable in background cenopopulations. It has been shown that a positive correlation exist between the initial viability of the seed progeny and their radioresistance. Chronic irradiation in a wide dose range induces an increased frequency of different mutations and morphological modifications. The contents of low-molecular antioxidants in seedlings from impact cenopopulations proved to be higher than in the background sample. The results obtained characterize the potential of protective and restorative mechanisms acquired in the course of evolution that allow plants to survive in the changing environment under exposure to technogenic stress.  相似文献   

13.
Variation in morphometric parameters of the poorly studied rare species Cephalaria uralensis (Murr.) Schrad. ex Roem. et Schult. has been studied at the northern boundary of its range, in the Southern Urals (Bashkortostan). The species in the region grows in four types of steppe communities of the class Festuco-Brometea. Variation in the majority of parameters is within the species reaction norm. The most variable parameters are the numbers of vegetative and generative shoots and the number of inflorescences per shoot. As shown by discriminant analysis, all 16 cenopopulations included in the study significantly differ from each other (Wilks’ λ = 0.21), with most of them being morphologically and structurally uniform. The state of local C. uralensis appears to be satisfactory, and this species is not at serious risk for extinction in the territory of Bashkortostan.  相似文献   

14.
A comparative study of the seed progeny of dandelions was performed with samples from cenopopulations growing for a long time under conditions of radioactive contamination (the zone of the Eastern Ural Radioactive Trace, EURT) or chemical pollution (the impact zone of the Nizhnii Tagil Metallurgical Plant, NTMP). The viability of seeds proved to decrease in a similar way along with an increase in technogenic pressure, irrespective of its nature. Experiments on acute exposure to heavy metals and γ-irradiation made it possible to reveal the adaptive capacities of the seed progeny from each cenopopulation. The background sample (formed beyond the zone of any impact) was relatively resistant to irradiation and very sensitive to heavy metals. The cenopopulations from the EURT and NTMP zones manifested nonspecific responses to the effects of both habitual and new factors.  相似文献   

15.
A study of allozyme spectra has been performed in dandelion cenopopulations growing for a long time under conditions of chemical pollution (the zone of the Nizhnii Tagil Metallurgical Plant, NTMP) or radioactive contamination (the zone of the Eastern Ural Radioactive Trace, EURT). Cenopopulations from the NTMP and EURT zones and from the background area differ significantly in the qualitative and quantitative composition of allozyme phenes. An analysis of clonal diversity has shown that all cenopopulations are phenogenetically unique. The genesis of each cenopopulation proceeded in a specific way: they had different sets of progenitor plants, whose descendants varied genetically in the course of their reproduction and more or less successful colonization of habitats, undergoing selection under the impact of natural environmental factors and technogenic stress. An increased variability of enzyme systems, compared to the sample from the background area, and, as a consequence, reduced clonal diversity may be regarded as a trait common to populations exposed to chemical or radiation stress.  相似文献   

16.
The viability and state of the prooxidant and antioxidant systems of Plantago major seed progeny from cenopopulations growing for a long time at the East-Ural Radioactive Trace (EURT) has been estimated. Radiation doses of maternal plants have been calculated using our empirical data in ERICA Tool. The absorbed dose rates for plantain in the EURT zone varied from 19 to 157 μGy/h, which is 178–1455 times higher than the background values. These relatively low levels of chronic irradiation did not cause a significant decrease in the survival rate of P. major seed progeny; the rate of root and leaf growth decreased only in seedlings from the most polluted cenopopulation. A prooxidant shift was revealed in seedlings from the EURT zone. Given the same regime of enzyme protection (SOD, CAT, and POX) against active oxygen forms, the average rate of accumulation of secondary products of lipid peroxidation (MDA) was 3.3 times higher in impact samples than in background samples. The level of prooxidant shift in impact samples is not linearly related to dose rates that are classified as low doses.  相似文献   

17.
基于上海城市气象站点数据、卫星遥感反演的土地利用数据、气象灾情记录数据和植被叶面积指数数据,运用层次分析法结合专家咨询法,建立了上海城市人居生态质量评价指标体系,并综合应用遥感和地理信息系统(GIS)空间分析技术,从湿润指数、气象灾害指数、水体密度指数、植被覆盖指数和植被质量指数开展了上海城市250m空间格网的人居生态质量评价和等级划分。结果表明:建立的评价指标体系对上海城市人居生态质量评价是可行的,上海人居生态质量在多数地区都为良或一般等级,在闵行、宝山和嘉定一些地区以及青浦和浦东个别地区人居生态质量为差,而在崇明北部和南部一些地区以及浦东、南汇和奉贤沿海极少地区人居生态质量为优等级。  相似文献   

18.
Variation of bilateral leaf structures in Middle Ural cenopopulations of the weeping birch (Betula pendula Roth.) growing in gradients of industrial pollution was studied to test the efficiency of a new method of population and individual phenogenetic monitoring allowing an indirect assessment of developmental destabilization by segregating the variance of total asymmetry (TA R 2) into its additive components, the variances of fluctuating asymmetry (FA R 2) and directional asymmetry (DA R 2). The method was tested in the impact zones of two copper-smelting plants in the Middle Urals. The degree of impact was characterized by the index of technogenic pollution (ITP) reflecting the average total contents of 15 water-soluble pollutants in snow samples. The level of asymmetry was estimated from the numbers of denticles with incoming veins (dentovenal elements) on the left and right leaf margins. Spearman’s coefficient of rank correlation between the group values of variance in fluctuating asymmetry (FA R 2) and corresponding ITP values reached r S = 0.914 (p < 0.001), providing evidence that the method is highly appropriate for ecological indication of the phenogenetic response of trees to environmental pollution.  相似文献   

19.
The endangered species Melica virgata was studied with respect to geographic distribution, the recent state of cenopopulations, the characteristics of habitats, phytocenotic relationships, morphology, and specific ecological and physiological features. The data on the introduction, biochemical composition, and economic significance of M. virgata are presented, and measures aimed at species conservation are proposed.  相似文献   

20.
Taking 248 A-share manufacturing listed companies in 2006 Shanghai Stock Exchange as example, using "index method" to measure level of environmental protection information disclosure, this paper examines the factors influencing level of environmental protection information disclosure. The findings show that the disclosure level has improved, but the overall level is still low and unable to satisfy information users; there is positive correlation between corporate size, industry type, accounting firm's type and corporate environmental disclosure index. The companies of large scale and heavy pollution and those audited by international "Big 4" and domestic "Big 10" accounting firms have a high level of environmental disclosure, while the profitability and financial leverage has no impact on the disclosure level. Finally some suggestions are put forward to establish environmental information disclosure system in China.  相似文献   

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