首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12篇
  免费   0篇
林业   6篇
农学   1篇
  5篇
  2019年   2篇
  2018年   1篇
  2017年   1篇
  2015年   1篇
  2014年   1篇
  2013年   1篇
  2006年   1篇
  2005年   1篇
  2004年   2篇
  2002年   1篇
排序方式: 共有12条查询结果,搜索用时 31 毫秒
1.
In Central Europe,a large portion of post-mining sites were afforested with Scots pine,which is characterized by good adaptability and a tolerance for poor habitat at the beginning of forest ecosystem development.Conversion of monoculture on mine sites into more biodiverse mixed hardwood forests,especially on more fertile deposits,can be an emerging need in this part of Europe in next decades.The ability to classify the forests at these post-mining sites will facilitate proper species selection as well as the management and formation of the developed ecosystem’s stability.This work describes the guidelines that can be followed to assess reclaimed mine soil(RMS)quality,using the mine soil quality index(MSQI)and a classification of developed forest sites as a basis of tree-stand species selection and conversion of pine monocultures.The research was conducted on four post-mining facilities(lignite,hard coal,sulphur,and sand pit mining areas)on different RMS substrates dominant in Central Europe.Soil quality assessment takes into account the following features of the soil:texture soil nutrients(Ca,Mg,K,Na,P);acidity(pH KCl);and Corg-to-Nt ratio in the initial organic horizon.An analysis was conducted of classification systems using the MSQI validation correlation(at p=0.05)with vegetation features affected by succession:aboveground biomass of forest floor and ecological indicators of vascular plants(calculated on the basis of Ellenberg’s(2009)system).Eventually,in the analysed data set,the MSQI ranged from0.270 for soils on quaternary sands to 0.720 for a mix of quaternary loamy sands with neogene clays.Potential forest habitat types and the role of the pine in the next generation of tree stands on different RMS parent rock substrate were proposed.  相似文献   
2.
In the technological processes of ore flotation in the non-ferrous metal industry flotation, tailings constitute up to 98% of the total of the processed material. They are stored in sedimentation ponds as fine-grained drift containing an excess of heavy metals, mainly zinc, cadmium, lead and copper. After the dehydration and drying up of the surface of sedimentation ponds, these metals are carried with dust by the wind and they are accumulated in the vicinity of the ponds in humus horizons of soils causing considerable degradation and even devastation. In this publication, we have presented the results of research on the negative influence of such a structure on the soils of an adjacent fragment of forest and its dependence on the distance from the sedimentation pond. The level of degradation of the soils under research has been assessed on the basis of changes and transformations of the morphological soil profiles, the level of alkalization and accumulation of heavy metals (Zn, Pb, Cd) in the topsoil layers and their translocation in the soil horizons. The following soils have been distinguished in the investigated area: Haplic Podzols distorted and degraded as well as Urbic Anthrosols. The acquired results have served to depict the spatial accumulation of these heavy metals in the topsoil layers. The highest accumulation of heavy metals and the degradation of the forest sites connected with it has occurred in the vicinity of a sedimentation pond drain channel. Soil remediation has been recommended in this area.  相似文献   
3.
This review on current biotechnological methods in forestry for in vitro tissue cultures to define the effect of stress conditions on trees,concentrates on somatic embryogenesis.Callus tissue,the key product of somatic embryogenesis,grows over a tree wound under ex vitro conditions.Callus tissue can be used in research in areas such as pathogenic susceptibility at the embryonic level,effect of heavy metals,influence of low temperatures(cryopreservation),production of secondary metabolites and transformation of plants.Callus of arborescent plants can be induced in vitro by fungal elicitors to produce secondary metabolites for pharmaceutical and cosmetic industries and are strongly repellant to herbivores and can thus act to protect forests.Analyses of dual cultures demonstrated that callus tissue exposed to a pathogenic fungus responds by synthesizing low-molecular-mass proteins belonging to an immune protein class.Cryopreservation of embryonic callus tissue also has broad applications,e.g.,for valuable plant genotypes in gene banks.Without strategies to protect forests against stressfactors,forest ecosystems will degrade to the detriment of all life,including humans.In vitro biotechnological research using callus tissue contributes to progress in forestry and the disciplines of ecology,physiology,phytopathology,culture and selection of plants.  相似文献   
4.
Summary The aim of this study was to investigate the efficiency of ISSR, SSR, and SAMPL marker systems in detecting genetic polymorphism among 30 winter rye inbred lines and to compare the results of cluster analysis performed on data from these marker systems using different statistical methods and coefficients. Each marker system was able to discriminate among the materials analyzed with the lowest value of average genetic similarity (GS) obtained with ISSR markers (0.2888) and the highest with SAMPLs (0.5381). EST-derived SSRs turned out to be less efficient in detecting genetic diversity than those from genomic libraries (average GS values 0.3814 and 0.3221, respectively). The average GS value for combined SSR data was 0.3569. The lack of correlations between similarity and cophenetic matrices obtained with various methods systems suggests that different marker systems should be used simultaneously for a genetic diversity study to exploit as many sources of polymorphisms as possible.  相似文献   
5.
Abstract

The work presents study results on the formation of humus horizons, the accumulation of organic carbon and nitrogen as well as humus composition in successional and reclaimed soils in a sand mine cast in southern Poland. Research plots were designed in chronosequence: 5, 17, 20 and 25 years. Increased thickness of humus horizon and accumulation of organic carbon was reported both in successional soils and in reclaimed soils. However, in corresponding age groups of reclaimed soils these characteristics were two times as high as in successional soils. The estimated accumulation rate of organic carbon (Corg) was three times higher and total nitrogen (Nt) five times higher in reclaimed soils than in successional soils. In both types of soils there was an increase in the amount of carbon trapped with humic and fulvic acid (CHa + CFa) and structure of humic acids. Studies indicated that reclamation treatment significantly accelerated soil-formation in opencast sand mine.  相似文献   
6.
Authentication of seed provenance is an importance issue to avoid the negative impact of poor adaptation of progenies when planted outside their natural environmental conditions. The objective of this study was to evaluate the potential of near infrared (NIR) spectroscopy as rapid and non-destructive method for authentication of Picea abies L. Karst seed provenances. For this purpose, five seed lots from Sweden, Finland, Poland and Lithuania each were used. NIR reflectance spectra were recorded on individual seeds (n = 150 seeds × 5 seed lots × 4 provenances = 3000 seeds) using XDS Rapid Content Analyzer from 780 to 2500 nm with a resolution of 0.5 nm. Classification model was developed by orthogonal projection to latent structures-discriminant analysis. The performance of the computed classification model was validated using two test sets—internal (the same seed lots as the model but excluded during model development; n = 600 seeds) and external (seed lots not included in the model; n = 1158 seeds). For the internal test, the model correctly recognized 99% of Swedish, Finnish and Polish samples and 97% of Lithuanian seeds. For the external test samples, the model correctly assigned 81% of Swedish, 96% of Finnish, 98% of Lithuanian and 93% of Polish seeds to their respective classes. The mean classification accuracy was 99 and 95% for internal and external test set, respectively. The spectral differences among seed lots were attributed to differences in chemical composition of seeds, presumably fatty acids and proteins, which are the dominant storage reserves in P. abies seeds. In conclusion, the results demonstrate that NIR spectroscopy is a very promising method for monitoring putative seed provenances and in seed certification.  相似文献   
7.
Fine roots play an important role in organic matter accumulation in reclaimed mine soils. However, estimation of the increment of fine root biomass is difficult and none of the existing methods is universal. The paper examined two methods for measurement of fine roots biomass increment (FRBI): i) with using the root-ingrowth core method (RIC) and ii) the monolith sampling method (MSC). The study was conducted under alder plantings (Alnus incana, A. glutinosa and A. viridis) introduced on technosols at a combustion waste disposal site and a former open-cast sand mine. The FRBI determined using MSC method was significantly lower (33–481 g m?2 yr?1) and less variable than the FRBI measured with RIC (85–2317 g m?2 yr?1). However, the results obtained with both methods were correlated (r = 0.70, P = 0,05). Consequently, MSC is better to qualitatively compare the habitats of tree species in terms of their ability to produce fine roots. However, in the initial soils where plants very often produce more fine roots, RIC seems to be more suitable. This method shows the actual ability of trees to produce roots in order to satisfy their life needs when acquiring a new habitat on reclaimed soils. Such information is particularly important in oligotrophic soils where nutrient deficiency may be balanced only by the efficient circulation and decomposition of organic matter (SOM) including the fine roots that die off after each growing season.  相似文献   
8.
The main objectives of our study were to evaluate soil contamination on a zinc-lead spoil heap in the Upper Silesian Industrial Region in southern Poland using pollution indices, and to investigate the relation between soil properties and the natural succession of vegetation. Organic carbon and nitrogen, pH, soil texture, base cations, and heavy metal content were analyzed in soil samples at depths of 0–15 cm below the organic horizon over a regular grid of 14 sampling plots. The contents of Zn, Pb, and Cd exceeded by several times the acceptable thresholds. Measurements of soil enzyme activity were used to evaluate the progress of vegetation development in relation to soil chemical properties. The results indicate that heavy metals had a significant impact on soil enzyme activity and the development of vegetation cover. High contents of Pb and Cd reduced enzyme activity, while this activity increased with increasing amounts of soil organic matter. Further, the accumulative capacities of heavy metals in needles of Scots pine (Pinus sylvestris L.) and aboveground biomass of bladder campion (Silene vulgaris (Moench) Garcke) were examined. A high accumulation of Zn, Pb, and Cd in the aboveground tissues of S. vulgaris indicated an unusual tolerance of this species to heavy metals and the possibility of using this species in phytoremediation of post-industrial sites.  相似文献   
9.
We examined the effects of nursery and field nutrient treatments on leaf chemistry and browsing during establishment of Eucalyptus globulus (two trials; Cressy and Dunalley) and Eucalyptus nitens (one trial; Tyenna) seedlings. Seedlings had high- or low-fertilizer application treatments in the nursery, were fertilized or not in the field and were individually fenced (used for leaf chemistry sampling) or not (used for browsing assessment). The high-fertilizer nursery treatment resulted in relatively high foliar nitrogen (N) and low tannin content (all seedling types), and high total essential oils (seedling batch planted at Cressy only), but nursery fertilizer level did not affect dry matter, neutral detergent (NDF) or acid detergent fibre (ADF) or lignin. After planting, levels of N, tannins and total essential oils changed over time, but the degree differed between sites. Field fertilizing generally had no effect on leaf chemistry during 10 weeks after planting. Across sites, the pattern of browsing was the same. Seedlings with the high-fertilizer nursery treatment were browsed more than the low-fertilizer nursery treatment, though the difference was only significant at two of the three sites. Thus trends in browsing damage were consistent with differences in foliar N and tannins as a result of nursery- and not field fertilizing treatment. Manipulation of seedling chemistry, using particular fertilizer application regimes in the nursery, may be one tool for managers wishing to decrease seedling damage by browsers, particularly when browsing severity is not extreme.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号