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1.
疆堇属的归并   总被引:1,自引:1,他引:0  
庄璇 《云南植物研究》1992,14(2):139-142
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2.
During World War II some professional botanists and graduate students who were drafted, enlisted, or commissioned in the armed forces were fortunate to be able to use their training directly or indirectly. This was especially true for the Pacific theatre. Others served their country as civilians. The roles of botanists in the military ranged from teaching or research to participation in combat or support operations. A few botanists in uniform, in spite of their occupational obligations, were able to collect botanical specimens and were encouraged to do so by civilian museum personnel. The best known projects for botanists as civilians involved the search for native supplies of strategic raw materials, particularlyCinchona andHevea, whileCryptostegia and Guayule, as possible sources of latex, were grown on plantations and studied in detail. Tropical problems of fungal deterioration of fabrics and optical equipment involved primarily civilian botanists in both military and academic laboratories. Some older botanists and those deferred for marital, dependent, or physical reasons served as instructors in regular academic programs or the special college programs for military personnel.  相似文献   

3.
At first glance botanical illustrations of the eighteenth century might be interpreted as being naturalistic portraits of living plants. A more detailed investigation, however, reveals that the pictures were meant to communicate typical features of plant species in the way of a model. To this end, botanists of the period gave botanical draughtsmen specialist training; copying earlier examples and standardised motives from drawing books was a common part of this training. The practice of copying elements of previously published drawings and integrating them into new pictures was also widespread. However, only carefully selected elements were taken over, and even these were improved in terms of their correctness and appropriateness to the new context. This procedure was a strategy that eighteenth-century botanists used so that they would present an illustration that met their own requirements more satisfactorily than existing depictions. From this perspective, botanical illustrations can serve as historical sources on the working practices of eighteenth-century botanists and draughtsmen, which are usually not mentioned in textual sources.  相似文献   

4.
By varying the thickness of the nervous tissue immersed in chlorate-osmic-formalin staining fluid (Swank and Davenport, 1935) it was found that a section 1 mm. thick can be completely and adequately stained in 24 hours. Thicker sections require a proportionately longer time. The quality of the Marchi stain in the rapidly prepared section is as good as that in the material stained for 10 days although the background is slightly lighter in the latter preparations. This method can be used where time is an important element and is especially applicable to spinal cord, small animal brains, or portions of larger brains in which serial sections are not required.  相似文献   

5.
By varying the thickness of the nervous tissue immersed in chlorate-osmic-formalin staining fluid (Swank and Davenport, 1935) it was found that a section 1 mm. thick can be completely and adequately stained in 24 hours. Thicker sections require a proportionately longer time. The quality of the Marchi stain in the rapidly prepared section is as good as that in the material stained for 10 days although the background is slightly lighter in the latter preparations. This method can be used where time is an important element and is especially applicable to spinal cord, small animal brains, or portions of larger brains in which serial sections are not required.  相似文献   

6.
In the genera Saxifraga, Saxifragodes, Saxifragella, Saxifragopsis and Zahlbrucknera foliar crystals were found to be present only in Saxifragodes and Saxifraga sections Micranthes and Irregulares . The crystals occur as stellate druses, except in Saxifraga nipponica and S. cortusifolia (section Irregulares ) where they occur as single needles. This finding indicates a close relationship between these two sections of Saxifraga . The monotypic Saxifragodes , from southern South America, does not appear to be related to Andean species of Saxifraga , which lack crystals, but rather to species of Saxifraga section Micranthes in North America. The taxonomic affinities of five species in section Micranthes that lack crystals are discussed.  相似文献   

7.
Botanists are an overlooked group of informants in ethnobotanical studies. The aim of this study was to assess their potential as sources of original ethnobotanical information. Wild food plants remembered by Polish botanists from their childhood were freelisted by 71 botanists. The results were compared with several ethnobotanical studies: three from the 21st century and one from the mid‐20th century. The botanists listed 123 species (mean of 9.3 species per individual). Although the average number of personal freelists was slightly lower for botanists than for local key informants in two of the other studies (11 and 13, respectively), the total list of species was longer than in any other Polish ethnobotanical study. Two of the ethnobotanical studies supplied richer material on past famine plants, whereas the botanists mentioned many alien plants and plants from urban habitats not mentioned in the ethnographical study. It can be concluded that botanists are possibly the best source of information for studies of contemporary or new uses of plants, but are inadequate for uses that are dying out. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 168 , 334–343.  相似文献   

8.
An improved method is described in which tissue areas can be initially identified in thick sections by light microscopy and isolated for subsequent ultrathin sections and observation by electron microscopy. This is achieved by embedding in hard Epon which can be sectioned at 25-150 μm on a sliding microtome after softening the blockface by applying a 60-70 C tacking iron to its surface immediately before each section is taken. The thick sections are then mounted on plastic slides to enable light microscopic selection of areas to be observed by electron microscopy. The selected areas are remounted on faced Epon blanks and resectioned at less than 50 nm. This technique makes it possible to obtain thick sections while maintaining an Epon hard enough for good serial ultrathin sections.  相似文献   

9.
Perspectives of diverse constituencies need to be incorporated when developing conservation strategies. In Menri (Medicine Mountains) of the Eastern Himalayas, Tibetan doctors and professional botanists were interviewed about conservation of useful plants. We compare these two perspectives and find they differ significantly in conservation priorities (Wilcoxon Signed Ranks P < 0.05), both in how they prioritized, as well as the priorities themselves. Tibetan doctors first consider which plants are most important to their medical practice and, then secondarily, the conservation status of these plants. Additionally, perceptions of threatened medicinal plants differ among Tibetan doctors who received medical training in Lhasa, who were local trained, and who were self-taught. In contrast, professional botanists came to a consensus among themselves by first considering the conservation status of plants and then considering use. We conclude that, in order to effect community based conservation, opinions from both Tibetan doctors and professional botanists should be considered in establishing conservation priorities and sustainable conservation programs. Furthermore, we set our own research agenda based on combined perspectives.  相似文献   

10.
Question: Could we better estimate plot species richness by asking several botanists to survey the same plots and using non‐parametric estimators of richness? Location: Two French deciduous forests. Methods: Using replicated, independent censuses made by 11 professional botanists on the same eight 100‐m2 forest plots, the relative performance of different richness estimators (Lincoln‐Petersen, Jackknife 1&2, Chao 1&2, Bootstrap, Chao Mth, Darroch) and the variation in their performance with the number of botanists involved (teams with two to eight botanists) were investigated. The sensitivity of these estimators to the presence of misidentifications in the data was also assessed. Results: When misidentifications are removed, Chao Mth estimators converged fastest to true richness, but none of the tested estimators correctly accounted for differences in exhaustiveness between the teams. Finally, all estimators were highly sensitive to misidentifications. Conclusions: Richness estimators are of little help in the presence of misidentifications and are ineffective at removing between‐team discrepancies, thus strongly limiting their usefulness in practice. Methods are presented to show how surveys can be designed to remove misidentifications and limit between‐team discrepancies. A sensible sampling design for 100‐m2 plots in temperate forests would involve triplets of botanists and correcting data with the Chao N1. Pairs of botanists would already significantly improve the richness estimates, but such estimates would still be biased low. However, further research is needed to design new richness estimators that are more robust to observer effects.  相似文献   

11.
王文采   《广西植物》1995,15(2):189-192
(1)在各种花对称的分类中,Ehrendorfer的分类包括了被子植物花对称方面从原始到进化的各种类型,最为全面广德国学者Strasburer在1911年编著的第11版植物学教科书中将具2对称面的荷包牡丹属的花称为bilateral或disymmetrisch.这个类型代表了被子植物花的一种较进化的构造,应该予以肯定。由于被指定为描述具2对称面的花的术语bilateral与被指定为描述具丑对称面的花的术语bilaterallysymmetrical颇为相似,而易引起混淆.为避兔发生混淆.建议不再应用这二术语.在描述具2对称面的花时,选用disymmetrical,中文译为双面对称的,在描述具1对称面的花时,选用zygomorphic(左右对称的)或monosymmetrical,后者的中文可译为单面对称的。(2)赞同将术语tepal译为花被片,而不赞同译为“被片”。  相似文献   

12.
Synopsis The histochemical method of Adamset al. (1966) for demonstrating triglycerides in tissue sections was applied to kidneys exhibiting a wide variety of disease states. It became apparent, as would be expected, that the existing method demonstrates not only triglycerides but also free fatty acids in the same section. Even though the presence of free fatty acids could be detected in the control sections, their existence made it impossible to identify triglycerides with certainty.A modification is described which employs a potassium hydroxide-dioxan mixture to saponify and extract selectively free fatty acids from tissue sections. Fatty acids in free form can be demonstrated separately, in parallel sections, from those esterified as triglyceride. This modified technique was applied to frozen sections of formalin-fixed human and rat tissues, revealing distinct and highly characteristic distribution patterns for these two forms of fatty acid.  相似文献   

13.
Abstract: Among members of the Orobanchaceae, parasitism has led to a drastic reduction in the morphological characters useful in identification. This is especially the case of species belonging to the subsection Minores (section Orobanche ), which is a real tangle for agronomists and botanists. In this study, more than 120 specimens collected in the west of France were studied for their morphological characters and molecular markers. Their rbcL plastid gene was analyzed by RFLP and nucleotide sequencing. Because of several substitutions, insertions and deletions in the coding sequence, leading to stop codons and frameshift, this rbcL gene could be considered as a pseudogene. Variations in both 5' upstream and coding regions allowed us to distinguish among specimens inside the Minores subsection. It was then possible to point out morphological characters, not used in floras, that fit with molecular analysis and confirm the existence of four taxa. Consequently, a new key to species determination using molecular analysis or morphological characters or a combination of both is proposed for O. hederae, O. amethystea, O. minor and O. loricata. Finally, the value of plastid pseudogenes in taxonomy is discussed.  相似文献   

14.
This is an historical paper examining the scientific background of George Ledyard Stebbins, Jr. (b. 1906), one of the foremost botanists of this century and one of the architects of the evolutionary synthesis, the intellectual event that brought together genetics and selection theory in the interval between 1920 and 1950. It considers his scientific influence and research, beginning with his Harvard education in 1924 and ending in 1950 with the publication of his book Variation and Evolution in Plants. The paper also more broadly assesses the contributions of other botanists to the evolutionary synthesis, including discussion of the work of Edgar Anderson (1897-1967) and others. It also traces the larger historical patterns of American botany, which saw a shift from East Coast botany as exemplified by Harvard botany, to West Coast botany, as exemplified by California botany.  相似文献   

15.
In microradiography the thickness of the specimen usually governs the degree of discrete structural detail attainable. A cause of poor detail in the historadiography of bone sections thinner than 30 micra is distortion attributable to lack of uniform contact between the undecalciiied specimen and the photographic emulsion. The use of a strong but radio-lucent supporting membrane on which the section can be mounted is an approach to the solution of this difficulty. Cementing the polished section under pressure to a 2 μ nylon membrane mounted on a modified specimen ring produces a flat section in close contact with the film. By mounting microtome-cut sections of frozen-dried developing bone directly on a supporting film of a polyvinyl resin, histochemical staining as well as microradiography can be performed on the same section.  相似文献   

16.
中国现代植物区系(地理)学的学派形成和展望   总被引:2,自引:0,他引:2  
简要回顾了中国近代植物区系 (地理 )学的历史。记述了吴征镒的植物区系的热带亲缘理论和张宏达的华夏植物区系理论的形成和主要特点 ,比较异同 ,以期通过他们及其研究群体联手协作 ,形成具有中国特色的植物区系学新学派  相似文献   

17.
A procedure is described in which thick sections (2-10 mu or more) of plastic-embedded plant tissues are mounted in serial order on slides for use in routine light microscopy. Sections are cut with a steel knife on a rotary microtome while the block and blade are bathed with 40% alcohol. The cut sections are placed, in order, in 50% alcohol in the small wells of modified plastic trays where they become flat, pliable and suitable for subsequent handling. Sections remain separate and in correct order in the trays while they are stained, washed, and prepared for final mounting on slides. Mounting involves a simple and rapid procedure of transferring the sections to a slide and heating first on a 70-75 C hot plate (to slowly evaporate the water around the section and to partially affix the section) and then on a C hot plate. This second heating ensures adhesion when xylene-base mounting media, which tend to loosen weakly adhered plastic from the slides, are used. The technique of staining the sections loose provides the following advantages: (1) the problems of section loss and entrapment of stain between section and slide during staining are eliminated, (2) relatively high staining temperature, alkalinity, and alcohol concentration of the stain solvent (all of which promote loosening of pre-affixed sections from slides during staining) is allowed, and (3) staining is more even and selective. The procedure has been found to be reliable and fast enough to be of value in a significant variety of routine light microscope studies.  相似文献   

18.
This article describes the slight impact of Lysenkoism upon Polish botany. I begin with an account of the development of plant genetics in Poland, as well as the attitude of scientists and the Polish intelligentsia toward Marxist philosophy prior to the World War II. Next I provide a short history of the introduction and demise of Lysenkoism in Polish science, with a focus on events in botany, in context with key events in Polish science from 1939 to 1958. The article outlines the little effects of Lysenkoism upon botanists and their research, as well as how botanists for the most part rejected what was often termed the “new biology.” My paper shows that though Lysenko’s theories received political support, and were actively promoted by a small circle of scientists and Communist party activists, they were never accepted by most botanists. Once the political climate in Poland altered after the events of 1956, Lysenko’s theories were immediately abandoned.  相似文献   

19.
The system of tree architecture proposed by Hallé and Oldeman consists of 23 models named after botanists playing leading roles in elucidating tree architecture. This system gives no indication why other models do not occur. A symbolism is presented here which can serve as a shorthand in recording tree architectures without assumptions about models. and immediately interpretable. Using this symbolism to represent the models proposed by Hallé and Oldeman permits creation of general rules of tree architecture. some of which raise interesting theoretical questions. Two further tree models that might well be expected to exist and several which would not be expected. are described.  相似文献   

20.
Phanerozoic mass extinctions have been studied primarily by analysing global diversity patterns compiled from the published literature. However, such compilations are beset by problems of incorrect correlation, imprecise age assignments and changing taxonomy. An alternative approach is to analyse mass extinctions by the ‘best sections’ method. This method identifies abundantly fossiliferous, well‐studied, stratigraphically dense and temporally extensive fossil records in strata that contain geochemical and other relevant non‐palaeontological data from a single depositional basin or geographically restricted outcrop area as the ‘best sections’ by which to analyse extinctions. A strength of the best sections method is that it allows the extinctions identified to be compared directly to changes in facies and other factors recorded in the best section. And, the hypothesis of a widespread extinction based on an extinction seen in a best section can be tested by its presence or absence in temporally equivalent sections. What we need are more field‐based studies of the best sections that encompass mass extinctions (real and hypothetical) and less of a reliance on literature‐based diversity compilations to produce a more reliable and comprehensive understanding of the history of extinctions.  相似文献   

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