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1.
The presence of several types of allelochemicals has been reported from Ajuga, a Labiatae genus comprising more than 40 species of wide distribution in extratropical regions of both hemispheres. The
genus is of great medicinal and economic importance and among the biological properties of the secondary metabolites, the
antifeedant activity against pest insects appears to be related to the presence of neo-clerodane type diterpenes. This review focuses on the isolation and structural elucidation of this type of compounds from
Ajuga species and the hemisynthetic compounds of closely related structure obtained. The reported biological activity of crude
extracts and isolated diterpenes will be briefly commented.
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Josep CollEmail: |
2.
Mycena aphanes and Mycena exilis, belonging to section Filipedes and section Polyadelphia, are proposed as new species. They are described and illustrated and compared to other species in the two sections. Mycena aphanes is a strikingly characteristic Mycena with fulvous or yellowish brown colours of both pileus and stipe. Mycena exilis is characterized by its occurrence on fallen Salix leaves, a pale brown pileus, occasionally with a pale pink tinge, narrowly adnate lamellae, four-spored basidia, and the
presence of clamp connections.
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Gro GuldenEmail: |
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4.
Augustine A. Ayantunde Mirjam Briejer Pierre Hiernaux Henk M. J. Udo Ramadjita Tabo 《Human ecology: an interdisciplinary journal》2008,36(6):881-889
Indigenous knowledge is unevenly distributed. Individual knowledge level may be affected by many factors such as gender, age,
ethnicity, profession, religious and cultural beliefs, abundance and usefulness of the species. This study documents indigenous
knowledge of herbaceous and woody plant species of farmers and herders in southwestern Niger. Specifically, we examine the
effects of age, gender, and ethnicity on knowledge of local vegetation. Results from the study showed that on average a higher
proportion of woody species was identified by the respondents compared to herbaceous species. Both gender and ethnicity had
a significant effect on the identification of herbaceous species but no effect on identification of woody species. Respondents
in lower age group (10 to 30 years) identified lower number of species compared to other age classes. There seems to be a
curvilinear relationship between age of respondents and number of plant species identified. Results from this study reaffirm
the uneven distribution of indigenous knowledge within a given area due to social factors. The main challenge is how to incorporate
these social differences in knowledge of native plant species into sustainable management and conservation of community natural
resources.
相似文献
Augustine A. AyantundeEmail: |
5.
Brad E. Erisman Jorge A. Rosales-Casián Philip A. Hastings 《Environmental Biology of Fishes》2008,82(1):23-33
The sexual pattern and sexual development of the leopard grouper, Mycteroperca rosacea, were investigated from 483 specimens collected from the Gulf of California, Mexico. Histological and population data indicated
a gonochoric sexual pattern. Some juveniles passed through an immature bisexual phase of gonadal development, but no evidence
of post-maturational sex change was found. The immature bisexual phase is believed to be associated only with male development.
The size distribution and size at sexual maturity were similar for both males and females. In accordance with predictions
of the size-advantage model, the gonochoric sexual pattern of M. rosacea is likely influenced by its group-spawning mating system.
相似文献
Brad E. ErismanEmail: |
6.
Summary The tree species Berlinia korupensis Mackinder & Burgt is described as new. The species is endemic to the southern part of
Korup National Park in Cameroon. Seventeen trees have been found so far, the largest being 42 m high and having a trunk diam.
of 88 cm. The new species is assessed as Critically Endangered (CR D) under the criteria of IUCN. Two distribution maps are
included; one map indicating the single locality in Cameroon near the Nigerian border where the new species was found and
another map of the permanent plot where 14 of the 17 trees were recorded. A line drawing is also included, along with colour
photographs of the flowers and the trunk.
相似文献
Barbara A. MackinderEmail: |
7.
Large-scale scientific computing applications frequently make use of closely-coupled distributed parallel components. The
performance of such applications is therefore dependent on the component parts and their interaction at run-time. This paper
describes a methodology for predictive performance modelling and evaluation of parallel applications composed of multiple
interacting components. In this paper, the fundamental steps and required operations involved in the modelling and evaluation
process are identified—including component decomposition, component model combination, M×N communication modelling, dataflow analysis and overall performance evaluation. A case study is presented to illustrate the
modelling process and the methodology is verified through experimental analysis.
相似文献
Stephen A. JarvisEmail: |
8.
M. Irfan-Ullah Giriraj Amarnath M. S. R. Murthy A. Townsend Peterson 《Biodiversity and Conservation》2007,16(6):1917-1925
Aglaia bourdillonii is a plant narrowly endemic to the southern portion of the Western Ghats (WG), in peninsular India. To understand its ecological
and geographic distribution, we used ecological niche modeling (ENM) based on detailed distributional information recently
gathered, in relation to detailed climatic data sets. The ENMs successfully reconstructed key features of the species’ geographic
distribution, focusing almost entirely on the southern WG. Much of the species’ distributional potential is already under
protection, but our analysis allows identification of key zones for additional protection, all of which are adjacent to existing
protected areas. ENM provides a useful tool for understanding the natural history of such rare and endangered species.
相似文献
M. Irfan-UllahEmail: Email: |
9.
Richard J. Robins Roland Molinié Renata A. Kwiecień Piotr Paneth Jacques Lebreton Trixie A. Bartholomeusz Albrecht Roscher Birgit Dräger Anna-Carolin Meier François Mesnard 《Phytochemistry Reviews》2007,6(1):51-63
The reaction of N-demethylation plays an important role in the degradation of some alkaloids in a number of organisms. This review presents
how our understanding of the N-demethylation of nicotine in plants has been improved through studies in cell cultures of Nicotiana plumbaginifolia and N. glutinosa using a variety of isotopic techniques. The overall aim is to understand how metabolism recycles the alkaloid skeleton, both
in terms of the metabolic route(s) exploited and the reaction mechanisms of the enzymes involved. The former has been approached
using high-resolution 2-dimensional NMR and GC-MS methods; the latter by determining kinetic isotope effects and modelling
the potential reaction steps. It appears that the mechanism for nicotine demethylation in plants is similar to but has significant
differences from that described for mammals and Pseudomonas bacteria. These differences are discussed.
相似文献
Richard J. RobinsEmail: |
10.
Competition for pollination is thought to be an important factor structuring flowering in many plant communities, particularly
among plant taxa with morphologically similar and easily accessible flowers. We examined the potential for heterospecific
pollen transfer (HPT) in a community of four Acacia species in a highly seasonal tropical habitat in Mexico. Partitioning of pollen flow among sympatric species appears to be
achieved, in part, through segregation of flowering in seasonal time, and interspecific differences in pollinator guilds.
However, two coflowering species (Acacia macracantha and Acacia angustissima) shared multiple flower visitors, raising the possibility of HPT. Each of these coflowering species showed high intraspecific
daily synchrony in pollen release, but dehisce at different times of day. Pollinators rapidly harvested available pollen from
one species before abandoning it to visit the flowers of the second later in the day. The activity of shared pollinators,
predominantly bees, is thus structured throughout the day, and potential for HPT reduced. Suggestive evidence in favour of
a resource partitioning explanation for this pattern is provided by the fact that A. macracantha showed significantly greater intraspecific synchrony when coflowering with a potential competitor (A. angustissima) than when flowering alone. We discuss our results in light of previous work on coflowering acacia assemblages in Tanzania
and Australia.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
Nigel E. RaineEmail: |
11.
H. Wernsdörfer T. Constant F. Mothe M. A. Badia G. Nepveu U. Seeling 《Trees - Structure and Function》2005,19(4):482-491
Frequently occurring red heartwood decisively restricts the volume of light-coloured beech wood, which can be processed to high-grade appearance products. Forestry and wood industry lack suitable means for maximising the yield of light timber, since the intra-tree extent of red heartwood varies considerably. The present study characterised in detail the intra-tree shape of red heartwood and its relationships to tree-external traits (dead branches, branch scars), considered as possible initiation points of red heartwood formation. An experimental method based on log scanning and image analysis was developed and applied. Using its output for three-dimensional visualisation and data analyses, external traits being linked to the local red heartwood shape were identified. Furthermore geometric relationships were established for characterising these external traits and for deriving discriminating criteria.
相似文献
H. WernsdörferEmail: |
12.
The maintenance of exceptionally high numbers of folk varieties by the Piaroa people of the Venezuelan Amazon is considered.
We cataloged 113 manioc folk varieties, their nomenclature, use and relevant characters, revealing significant insights into
the role of manioc in Piaroa social life. Through a qualitative investigation of the cultivation, processing and symbolic
significance of manioc (Manihot esculenta) in two Piaroa regions over a period of 18 years, we have found that such agrobiodiversity can only be fully explained by
a combination of multiple factors, including pragmatic and ecological considerations, the subtle and complex diversity of
Piaroa manioc preparations and a variety of sociocultural factors, such as manioc’s role as a mediator of social relationships
and as a marker of cultural and social heritage.
相似文献
Stanford ZentEmail: |
13.
Despite growing interest in traditional and local ecological knowledge for conservation and resource management, the role of migrant resource users is largely unexplored. Challenging many assumptions about what constitutes “local knowledge,” migrant and immigrant harvesters of non-timber forest products on the Olympic Peninsula, Washington possess useful ecological knowledge of overstory–understory relationships and how forestry practices affect understory biological and commercial production. Harvesters of salal (Gaultheria shallon), a shrub used in the multi-million dollar floral greens industry, were interviewed in Mason County, Washington in 2001–2003. Interviews revealed that harvesters possess different kinds of resource management knowledge depending on whether they are experienced harvesters or more recent newcomers to the area. These differences may also correlate with differences in their harvesting practices. Understanding how resource management knowledge differs between experienced and newcomer harvesters can inform forest managers in their efforts to develop effective management and permitting policies for floral greens and other non-timber forest resources in the Pacific Northwest of the United States.
相似文献
Heidi L. BallardEmail: |
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16.
Paul F. Cannon Nigel L. Hywel-Jones Norbert Maczey Lungten Norbu Tshitila Tashi Samdup Phurba Lhendup 《Biodiversity and Conservation》2009,18(9):2263-2281
The insect-pathogenic fungus Ophiocordyceps sinensis (better known as Cordyceps sinensis) is harvested over much of the Himalayan plateau as a highly prized remedy in traditional Oriental medicine. Over the past
10 years its financial value has increased dramatically, with collectors paid as much as US $12,500 kg−1 for top-quality material. This is causing significant distortion to local economies, and there is widespread concern that
the current rate of collection is unsustainable. This paper introduces the fungus and its insect hosts, documents some of
the biological and social constraints to achieving sustainability, describes the socioeconomic climate within which harvest
and sale occurs in Bhutan, and details the measures put in place by the Royal Government of Bhutan to promote wise management
of this valuable natural resource.
相似文献
Paul F. CannonEmail: |
17.
Grant Murray Barbara Neis Jahn Petter Johnsen 《Human ecology: an interdisciplinary journal》2006,34(4):549-571
Questions centered on the development of local and traditional ecological knowledge and the relationship of that knowledge to the development of conservation and management practices have recently attracted critical attention. We examine these questions with respect to the dynamic commercial fisheries of the Canadian province of Newfoundland and Labrador. The knowledge of fish harvesters coevolves with fishing practices and is embedded in a dynamic socioecological network that extends into and beyond the fisher, fishery households, and communities to include management, technologies, markets, and marine ecological conditions. Changes in these networks have moved knowledge and practices related to fishing in directions defined by policy, science, economic rationality, and new ecological realities. We characterize this movement as a shift along a continuum from local ecological knowledge (LEK) towards globalized harvesting knowledge (GHK) as harvesters become increasingly disconnected from socioecological relationships associated with traditional species and stocks. We conclude with a discussion of how LEK/GHK have interacted over time and space with other knowledge systems (particularly science) to influence management, and suggest that contingent, empirical evaluations of these interactions will provide a fruitful avenue for future interdisciplinary research.
相似文献
Grant MurrayEmail: |
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19.
A new freshwater oligochaete species (Clitellata: Enchytraeidae) from Livingston Island,Antarctica 总被引:2,自引:0,他引:2
The new enchytraeid species Lumbricillus healyae sp. n. is described from freshwater streams, with well-oxygenated and poorly mineralised waters, situated in Byers Peninsula
(Livingston Island, South Shetland Islands, Antarctica). Lumbricillus healyae sp. n. is morphologically close to L. antarcticus and L. incisus, and it is mainly distinguished by the structure of the spermatheca with a short, distinct ectal duct, the oval penial bulb
(greatest diameter in the transverse body axis) associated with strong dorso-ventral muscular fibres, and a protrusible pseudopenis.
A second undetermined Lumbricillus species is described from a small stream. Study specimens are not fully mature; however, the highly irregular form and size
of the testis-sac lobes and the absence of a penial bulb encapsulated under a muscular layer are remarkable. It is probably
related to a small group of Lumbricillus species reported from the Antarctic maritime region (L. colpites, L. griseus and L. aestum), characterised by the structure of the male duct, which ends in a simple pore surrounded by glands.
相似文献
Eugenio RicoEmail: |
20.
D. Gelli V. Ferrari A. Zanella P. Arena L. Pozzi S. Nannarelli C. Vaccaro D. Bernardini S. Romagnoli 《European Journal of Wildlife Research》2009,55(1):59-63
The loggerhead sea turtle (Caretta caretta), one of the three sea turtle species inhabiting the Mediterranean Sea, is an endangered species. However, although frequently
treated in marine animal rescue centers, and the subject of several studies in literature, as yet, few studies have been conducted
on large numbers of loggerhead sea turtles in order to establish physiological reference ranges that enable the identification
of pathological values. The lack of studies on reference parameters probably depends on the fact that marine turtles treated
in wildlife rescue centers are usually in a critical conditions, thus precluding the collection of data on healthy animals
and compromising the reliability of any data obtained from them. The present biological study was therefore conducted in order
to obtain a database from healthy animals in natural conditions. Serum biochemistry and serum protein electrophoresis were
performed on blood samples obtained from 65 healthy adult loggerhead sea turtles captured and delivered to the Sea Turtle
Rescue Center of Linosa (Italy); the blood samples were collected during the clinical examination of rescued animals. Laboratory
analyses of serum samples were made in order to establish reference parameters, commonly required for laboratory diagnoses
in mammals and diseased animals.
相似文献
D. GelliEmail: |