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林蛙在中国的分布 总被引:7,自引:2,他引:5
作者收集有关我国林蛙分布的资料绘制了林蛙分布图,其中图1标明了主要分布于中国北方的中国林蛙种绀(Rana chensinensis species-group)和黑龙江林蛙种组(R.amurensis species-group)的分布,图2标明出了在亲缘关系上与日本林蛙很相近(R.jaonica)的分布于南方的长肢林蛙种组(R.longicrus species-group)的分布,图3重点标明了环渤海区域已知6种林蛙的分布。最后,作者提出环渤海区域是林蛙重要的分布中心,并对镇海林蛙(R.zhenhaiensis)和中国林蛙(R.chensinensis)的一些可疑或有争议的分布问题进行了简要讨论。 相似文献
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生活史的研究可以为系统发育研究和珍稀濒危物种的保护和管理对策的制定提供参考资料。林蛙是我国分布比较广泛而复杂多样的一个类群,在山东半岛的昆嵛山和崂山,分别分布有昆嵛林蛙(Rana kunyuensis)和中国林蛙(R.chensinensis)。本文报道我们从1997年到2006年,对这两种林蛙在山东半岛的地理分布、繁殖习性、蝌蚪特征和生长发育以及冬眠等方面的调查和观察研究结果。结果表明昆嵛林蛙和分布于崂山的中国林蛙尽管在栖息地生境方面比较相似,但在生活史方面表现出较大的不同。 相似文献
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四种林蛙核型及银带研究 总被引:5,自引:1,他引:4
林蛙又称棕蛙(brownfrog),是广布欧洲、亚洲和北美洲的一个自然类群,约有28种,我国记载达10种(谢锋,1995)。国内对2n=26的林蛙染色体研究报道主要有李树深等(1981,1982)、王子淑等(1983)、陈文元等(1983)、韦今来(... 相似文献
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目的中国林蛙(Rana chensinensis David,1875)是我国林蛙属分布最为广泛的特有种,在上一世纪对其分类问题多有争议,曾被认为广布于中国、蒙古、俄罗斯、日本和朝鲜半岛等。随着对其分类地位的确定,其分布范围也发生了很大变化。为了保护和可持续利用这一重要资源,本文对其分类研究历史和分布进行了总结。方法通过收集、整理和分析研究文献,结合本实验室多年来掌握的野外资料,进行系统的总结。结果中国林蛙自1875年由戴维(中文名为谭卫道)命名以来,曾被划归欧洲林蛙的亚种,并将多种其他林蛙归并入其下。1981年,经过细胞分类学研究,正式恢复为有效种,随后进一步划分出5个亚种。直至本世纪初,经过进一步的分类学研究,厘清了其与东北林蛙和西北林蛙的关系,从而确定其为仅分布于中国的特有种。在此基础上,对其分布也进行了重新确立。结论中国林蛙隶属于蛙科林蛙属中国林蛙种组,目前没有种下分化和亚种形成,分布于我国华北、华中及其周边地区,分布海拔不高于2500m。 相似文献
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东北林区半人工养殖林蛙对当地自然生态保护影响的调查与分析 总被引:1,自引:0,他引:1
应用资料收集法和实地调查法,调查、评估并分析了东北林蛙养殖区域自然生态变化趋势、东北林蛙养殖业从业人员行为的影响及养殖业发展的可持续性.结果表明开展林蛙半人工养殖的区域几乎全部是自然生态状况良好、具有重要保护价值的区域;林蛙半人工养殖方式极大地提高了区域性森林生态系统中林蛙的数量,进而将导致自然生态系统发生一系列变化,这些变化对自然生态状况的影响有利有弊,并存在不确定性;林蛙养殖从业人员的从业行为或行为倾向,既有有利于当地自然生态保护的一面,也有不利于当地自然生态保护的隐患.在调查与分析的基础上,提出了如下建议:加强林蛙资源本底调查,坚持对林蛙半人工养殖区域自然生态变化的监测和研究,统一林蛙半人工养殖区域各经营活动的经营权,研究制定东北林蛙半人工养殖技术规范,引导从业人员规范操作等. 相似文献
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P. N. Diouf N. Delbarre D. Perrin P. Grardin C. Rapin J. P. Jacquot E. Gelhaye 《Applied microbiology》2002,68(9):4377-4382
Fenton reactions are believed to play important roles in wood degradation by brown rot fungi. In this context, the effect of tropolone (2-hydroxycyclohepta-2,4,6-trienone), a metal chelator, on wood degradation by Poria placenta was investigated. Tropolone (50 μM) strongly inhibits fungal growth on malt agar, but this inhibition could be relieved by adding iron salts. With an experimental system containing two separate parts, one supplemented with tropolone (100 μM) and the other not, it was shown that the fungus is able to reallocate essential minerals from the area where they are available and also to grow in these conditions on malt-agar in the presence of tropolone. Nevertheless, even in the presence of an external source of metals, P. placenta is not able to attack pine blocks impregnated with tropolone (5 mM). This wood degradation inhibition is related to the presence of the tropolone hydroxyl group, as shown by the use of analogs (cyclohepta-2,4,6-trienone and 2-methoxycyclohepta-2,4,6-trienone). Furthermore, tropolone possesses both weak antioxidative and weak radical-scavenging properties and a strong affinity for ferric ion and is able to inhibit ferric iron reduction by catecholates, lowering the redox potential of the iron couple. These data are consistent with the hypothesis that tropolone inhibits wood degradation by P. placenta by chelating iron present in wood, thus avoiding initiation of the Fenton reaction. This study demonstrates that iron chelators such as tropolone could be also involved in novel and more environmentally benign preservative systems. 相似文献
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Montserrat Vilà Amparo Carrillo-Gavilán Jordi Vayreda Harald Bugmann Jonas Fridman Wojciech Grodzki Josephine Haase Georges Kunstler MartJan Schelhaas Antoni Trasobares 《PloS one》2013,8(2)
Background
Despite empirical support for an increase in ecosystem productivity with species diversity in synthetic systems, there is ample evidence that this relationship is dependent on environmental characteristics, especially in structurally more complex natural systems. Empirical support for this relationship in forests is urgently needed, as these ecosystems play an important role in carbon sequestration.Methodology/Principal Findings
We tested whether tree wood production is positively related to tree species richness while controlling for climatic factors, by analyzing 55265 forest inventory plots in 11 forest types across five European countries. On average, wood production was 24% higher in mixed than in monospecific forests. Taken alone, wood production was enhanced with increasing tree species richness in almost all forest types. In some forests, wood production was also greater with increasing numbers of tree types. Structural Equation Modeling indicated that the increase in wood production with tree species richness was largely mediated by a positive association between stand basal area and tree species richness. Mean annual temperature and mean annual precipitation affected wood production and species richness directly. However, the direction and magnitude of the influence of climatic variables on wood production and species richness was not consistent, and vary dependent on forest type.Conclusions
Our analysis is the first to find a local scale positive relationship between tree species richness and tree wood production occurring across a continent. Our results strongly support incorporating the role of biodiversity in management and policy plans for forest carbon sequestration. 相似文献13.
An Overview of the Biology of Reaction Wood Formation 总被引:1,自引:0,他引:1
Sheng Du Fukuju Yamamoto 《植物学报(英文版)》2007,49(2):131-143
Reaction wood possesses altered properties and performs the function of regulating a tree's form, but it is a serious defect in wood utility. Trees usually develop reaction wood in response to a gravistimulus. Reaction wood in gymnosperms is referred to as compression wood and develops on the lower side of leaning stems or branches. In arboreal, dicotyledonous angiosperms, however, it is called tension wood and is formed on the upper side of the leaning. Exploring the biology of reaction wood formation is of great value for the understanding of the wood differentiation mechanisms, cambial activity, gravitropism, and the systematics and evolution of plants. After giving an outline of the variety of wood and properties of reaction wood, this review lays emphasis on various stimuli for reaction wood induction and the extensive studies carried out so far on the roles of plant hormones in reaction wood formation. Inconsistent results have been reported for the effects of plant hormones. Both auxin and ethylene regulate the formation of compression wood in gymnosperms. However, the role of ethylene may be indirect as exogenous ethylene cannot induce compression wood formation. Tension wood formation is mainly regulated by auxin and gibberellin. Interactions among hormones and other substances may play important parts in the regulation of reaction wood formation. 相似文献
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木材的物理力学属性制约树木生长发育的重要过程,也是决定木材用途的主要依据.研究木材的物理力学属性及其影响因素,可为合理应用木材、科学开展林木选育、改进林业管理等提供必要参考.目前已有的研究多关注单一的木材密度指标,且缺乏多种影响因子的比较.本研究通过建立中国木材物理力学属性及影响因素综合数据库,对自然状态下我国主要树种木材力学属性的分布格局及其驱动因素进行了探讨.结果表明,选择气干密度、弦向干缩系数和冲击韧性作为评估木材物理力学属性的基础指标,比单一木材密度指标更准确,解释率更高;在选用的生活型、气候和土壤等3类因素中,生活型是影响木材力学物理属性变化的最重要因素,气候因子次之,土壤因子基本可忽略,并且气候和土壤因子的作用被生活型所掩盖,这意味着气候因子对于木材物理力学属性的影响是通过影响物种分布而产生作用的. 相似文献
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Wood decay under the microscope 总被引:3,自引:0,他引:3
Many aspects of the interactions between host wood structure and fungal activity can be revealed by high resolution light microscopy, and this technique has provided much of the information discussed here. A wide range of different types of decay can result from permutations of host species, fungal species and conditions within wood. Within this spectrum, three main types are commonly recognised: brown rot, white rot and soft rot. The present review explores parts of the range of variation that each of these encompasses and emphasizes that degradation modes appear to reflect a co-evolutionary adaptation of decay fungi to different wood species or the lignin composition within more primitive and advanced wood cell types. One objective of this review is to provide evidence that the terms brown rot, white rot and soft rot may not be obsolete, but rigid definitions for fungi that are placed into these categories may be less appropriate than thought previously. Detailed knowledge of decomposition processes does not only aid prognosis of decay development in living trees for hazard assessment but also allows the identification of wood decay fungi that can be used for biotechnology processes in the wood industry. In contrast to bacteria or commercial enzymes, hyphae can completely ramify through solid wood. In this review evidence is provided that wood decay fungi can effectively induce permeability changes in gymnospermous heartwood or can be applied to facilitate the identification of tree rings in diffuse porous wood of angiosperms. The specificity of their enzymes and the mild conditions under which degradation proceeds is partly detrimental for trees, but also make wood decay fungi potentially efficient biotechnological tools. 相似文献
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Roland Hischier Hans-Jörg Althaus Frank Werner 《The International Journal of Life Cycle Assessment》2005,10(1):50-58
Goal, Scope and Background This paper gives an overview on how the wood and packaging material production is inventoried in ecoinvent. Packaging materials have been a very important topic in the area of Life Cycle Assessment for more than twenty years. Wood is the most important renewable material and regenerative fuel used worldwide, and an important raw material for paper / board. Several methodological problems arising when inventorying wood for material and energetic uses in a generic database are discussed in more detail. Within the ecoinvent project, the Swiss data base for life cycle inventory data, two reports are dedicated to these two important topics report No. 9 for wood and report No. 11 for packaging materials. Methods The whole wood chain has been modeled in a consistent way. This allows one to use this data for LCAs of building materials, bioenergy or paper production. The data represent average technologies used in Central Europe in the year 2000. A revenue-based co-product allocation approach is used for the different outputs. Correction factors are introduced for the consistent modeling of mass-based, material inherent wood properties such as solar energy, carbon uptake and land use. For packaging materials, the datasets represent European average data for the most often used materials as well as specific datasets for the production of actual packaging boxes and containers.Results and Discussion For wood, revenue-based allocation and the use of the correction factors for mass-related wood properties are shown and explained. For packaging materials, the importance of the raw material wood to the total load is shown. Furthermore trends in the data inventories for board packaging materials over the last two decades are discussed: mainly due to the increased comprehensiveness of the data, higher cumulative emissions can be observed. Conclusion For wood, the database ecoinvent provides consistent datasets for the entire chain from forestry to intermediate products such as timber, different types of wood-based boards, chips, pellets, etc. For packaging materials, the number of datasets of basic materials has been extended. A modular concept for actual packaging container datasets allows the user an easy modeling of various types of packaging containers/boxes. In the area of paper and board, a comprehensive database for the production of various types of pulp, paper and board is provided, which is representative for the average European production situation. Outlook Since wood is only limited and representative data for Europe is therefore not included, an update in the near future would be reasonable. Possible further extensions in the future could include various, final wooden products. For the data on paper/board, different levels of quality are observed, requiring a selective up-date of these data. Future extensions could include datasets for the import of pulp from overseas especially from South America and Canada. 相似文献
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橡胶树是中国重要的热带经济作物,橡胶种植的副产物橡胶木是我国木材供应的重要来源。我们以不同发育阶段的橡胶树幼茎木材为材料,借助扫描电子显微镜技术,对木质部细胞的超微结构进行了观察。结果表明,在橡胶树幼茎木材中,导管和木纤维细胞壁随着木质部发育成熟会发生明显的次生加厚,加厚方式主要为螺纹加厚;木质部各类型细胞均存在大量纹孔,纹孔排列方式主要有散生、网状、梯状和单串状等类型;在木质部发育过程中,木射线和部分薄壁细胞中会逐渐积累大量淀粉粒;木质部细胞内壁及其填充物表面存在不同类型的附着物。研究结果将为橡胶木材材性及其形成机制的研究提供一定理论参考。 相似文献
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Chunia is a monotype of Hamamelidaceae in China. The wood structure of this genus possesses some primitive properties, such as the inclining end-wall of vessel elements, the scalariform perforation plates, the absence of spiral thickening in the wall, the heterogenous rays, crystal inclusion in Cell, and scanty parenchymatous cells in the axial system. On account of its intimate relation to the genus Mytilaria, therefore, both may be represented as primitive genera in this family. 相似文献
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During the first year of hybrid poplar development, we assessed radial growth dynamics quantified by the proportion of secondary xylem tissue within the stem area, the vessel area percentage, the content of both lignin and cellulose, the lignin monomeric composition, and the macromolecular properties of cellulose. The intraannual radial growth dynamics in the proportion of secondary xylem tissue was fitted by the Gompertz regression line whereas changes in the vessel area percentage were fitted maximally by a cubic regression line. Under constant temperature and photoperiod, this study revealed that nonlinear patterns of radial growth dynamics are the result of a developmental programme which drives cambial activity and ageing. The increased proportion of guaiacyl units found may be important for the greater stability of the lignin structure in the first year of hybrid poplar development. The tensile strength of juvenile wood was ensured by the trade-off between a slight increase in the degree of polymerization of cellulose and a slight decrease in the content of cellulose during ageing. 相似文献