首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Quantifying the Trade in Cycads ( Encephalartos Species) in the Traditional Medicine Markets of Johannesburg and Durban, South Africa. Cycads have been used for traditional purposes for centuries, mainly as a source of starch during droughts and famines. In South Africa, Encephalartos species are traded for traditional medicine (TM) in local TM markets. The 2009 IUCN Red Data assessment for South African flora lists 78% of the 37 indigenous Encephalartos species as “Threatened”, with three species already “Extinct in the Wild” (EW). South African cycads face an extinction crisis, primarily due to collecting for the horticultural trade. The trade in Encephalartos for TM also has a significant impact on several species, and is largely understudied. In this paper, the trade in Encephalartos for TM was quantified in South Africa’s two largest TM markets, Faraday in Johannesburg and Warwick in Durban. Harvesting of South African Encephalartos for TM involves the removal of bark strips and/or whole stem sections. Encephalartos species were sold at 26% and 13% of the stalls at Faraday and Warwick, respectively, with an estimated 9.0 metric tons traded at Warwick in 2009. Stem samples purchased in the markets were assigned to stem diameter size classes using a size class chart, and regression analysis was used to validate the allocations. Most harvesting was from sub-adult and adult cycads, and it appears that bark strips are removed from large arborescent plants, whereas smaller individuals and subterranean-stemmed species are harvested by removing the entire plant. There is generally a positive relationship between stem diameter and leaf base length as well as stem diameter and pith radius. The former can be used as a predictor of stem diameter size class for market samples that prove difficult to assign to diameter classes using the chart. Overall, this is the first study to quantify the trade in Encephalartos for TM in South Africa with reference to the size classes of the plants traded.  相似文献   

2.
Africa hosts a rich assemblage of cycads: 66 Encephalartos species, Stangeria eriopus and Cycas thouarsii. Most Encephalartos and S. eriopus adults appear to be fire-tolerant, and certain Encephalartos species may be fire-dependent. Four Encephalartos species and S. eriopus are primarily insect-pollinated. African cycad populations typically have sex ratios of 1:1, with very small populations often male-biased. Coning is typically infrequent and erratic, with many species exhibiting mast-seeding. Viable seed production in Encephalartos populations tends to decline with decreasing population size, and seed predation by weevils is common. Seed dispersal in Encephalartos is usually localized, but vertebrates may facilitate dispersal over longer distances. Stem material of 25 Encephalartos species and S. eriopus is used for traditional medicine, primarily in South Africa. Two-thirds of Africa’s cycad species are threatened, with four species already Extinct in the Wild. The illegal acquisition of cycads from wild populations is the principle threat to their persistence. Further research is recommended on seed and fire ecology, population dynamics, and the outcomes of conservation interventions.  相似文献   

3.
4.
The genus Plectranthus (Lamiaceae) is a significant, prolific and extensively used genus in southern Africa. It plays a dominant role in both horticulture and traditional medicine. Some 12 species are documented for their use in treating ailments by various indigenous peoples of southern Africa. It is a firm favourite in gardens and Plectranthus has been bred to further utilise the remarkable diversity of indigenous South African wildflowers with amenity horticultural potential. Although previously subjected to both horticultural (Van Jaarsveld, 2006) and ethnobotanical (Lukhoba et al., 2006) review, Plectranthus is a genus with economic potential in various sectors, and this article aims to review this potential of southern African species.  相似文献   

5.
Medicinal plants cover a broad range of taxa, which may be phylogenetically less related but morphologically very similar. Such morphological similarity between species may lead to misidentification and inappropriate use. Also the substitution of a medicinal plant by a cheaper alternative (e.g. other non-medicinal plant species), either due to misidentification, or deliberately to cheat consumers, is an issue of growing concern. In this study, we used DNA barcoding to identify commonly used medicinal plants in South Africa. Using the core plant barcodes, matK and rbcLa, obtained from processed and poorly conserved materials sold at the muthi traditional medicine market, we tested efficacy of the barcodes in species discrimination. Based on genetic divergence, PCR amplification efficiency and BLAST algorithm, we revealed varied discriminatory potentials for the DNA barcodes. In general, the barcodes exhibited high discriminatory power, indicating their effectiveness in verifying the identity of the most common plant species traded in South African medicinal markets. BLAST algorithm successfully matched 61% of the queries against a reference database, suggesting that most of the information supplied by sellers at traditional medicinal markets in South Africa is correct. Our findings reinforce the utility of DNA barcoding technique in limiting false identification that can harm public health.  相似文献   

6.
Hydnora spp. are rarely collected root holoparasites due to the subterranean nature of the rhizomes and seasonal emergence of the flowers. Results from a recent study in South African traditional medicine markets positively identified Hydnora abyssinica A.Br. rhizomes in trade and indicated that there was a high probability of the species also occurring in southern Mozambique. An ethnobotanical study was thus conducted in two markets in Maputo, and the presence of H. abyssinica at the stalls of traditional medicine sellers is a new record for the species' occurrence in Mozambique. Most of the rhizomes were cited as being harvested in the districts of Boane and Manhica, and further research is required to verify the harvesters' accounts of its distribution.  相似文献   

7.

Background and Aims

Ontogenetic patterns of odour emissions and heating associated with plant reproductive structures may have profound effects on insect behaviour, and consequently on pollination. In some cycads, notably Macrozamia, temporal changes in emission of specific odour compounds and temperature have been interpreted as a ‘push–pull’ interaction in which pollinators are either attracted or repelled according to the concentration of the emitted volatiles. To establish which mechanisms occur in the large Encephalartos cycad clade, the temporal patterns of volatile emissions, heating and pollinator activity of cones of Encephalartos villosus in the Eastern Cape (EC) and KwaZulu Natal (KZN) of South Africa were investigated.

Methods and Key Results

Gas chromatography–mass spectrometry (GC-MS) analyses of Encephalartos villosus cone volatiles showed that emissions, dominated by eucalyptol and 2-isopropyl-3-methoxypyrazine in EC populations and (3E)-1,3-octadiene and (3E,5Z)-1,3,5-octatriene in the KZN populations, varied across developmental stages but did not vary significantly on a daily cycle. Heating in male cones was higher at dehiscence than during pre- and post-dehiscence, and reached a maximum at about 1830 h when temperatures were between 7·0 and 12·0 °C above ambient. Daily heating of female cones was less pronounced and reached a maximum at about 1345 h when it was on average between 0·9 and 3·0 °C above ambient. Insect abundance on male cones was higher at dehiscence than at the other stages and significantly higher in the afternoon than in the morning and evening.

Conclusions

There are pronounced developmental changes in volatile emissions and heating in E. villosus cones, as well as strong daily changes in thermogenesis. Daily patterns of volatile emissions and pollinator abundance in E. villosus are different from those observed in some Macrozamia cycads and not consistent with the push–pull pattern as periods of peak odour emission do not coincide with mass exodus of insects from male cones.  相似文献   

8.
South African citrus thrips (Scirtothrips aurantii) is a pest of citrus, mango and other horticultural species in its native range, which encompasses a large part of Africa. Its adventitious establishment in Australia in 2002 was a major cause for concern. The thrips, 11 years after its incursion into Australia, has remained on plants of a single host plant genus Bryophyllum (Crassulaceae). Characterization of the Specific-Mate Recognition System of the Bryophyllum population of thrips present in Australia and behavioral bioassay experiments revealed that compounds found in the insects’ body extracts play a crucial role in mate recognition of S. aurantii. Reciprocal cross-mating experiments between the Australian Bryophyllum insects and South African S. aurantii from horticultural host plants showed that mating frequencies were significantly lower in test crosses (Bryophyllum x horticultural) than in controls (Bryophyllum x Bryophyllum or horticultural x horticultural), which indicates there are at least two distinct species within S. aurantii and suggests further tests of this interpretation. The results suggest that these tiny phytophagous insects localize mates through their association with a particular host plant species (or closely-related group of species). Also, specific tests are suggested for clarifying the species status of the host-associated populations of S. aurantii in Africa.  相似文献   

9.
Few regional or continent-wide assessments of bird use for traditional medicine have been attempted anywhere in the world. Africa has the highest known diversity of bird species used for this purpose. This study assesses the vulnerability of 354 bird species used for traditional medicine in 25 African countries, from 205 genera, 70 families, and 25 orders. The orders most represented were Passeriformes (107 species), Falconiformes (45 species), and Coraciiformes (24 species), and the families Accipitridae (37 species), Ardeidae (15 species), and Bucerotidae (12 species). The Barn owl (Tyto alba) was the most widely sold species (seven countries). The similarity of avifaunal orders traded is high (analogous to “morphospecies”, and using Sørensen''s index), which suggests opportunities for a common understanding of cultural factors driving demand. The highest similarity was between bird orders sold in markets of Benin vs. Burkina Faso (90%), but even bird orders sold in two geographically separated countries (Benin vs. South Africa and Nigeria vs. South Africa) were 87% and 81% similar, respectively. Rabinowitz''s “7 forms of rarity” model, used to group species according to commonness or rarity, indicated that 24% of traded bird species are very common, locally abundant in several habitats, and occur over a large geographical area, but 10% are rare, occur in low numbers in specific habitats, and over a small geographical area. The order with the highest proportion of rare species was the Musophagiformes. An analysis of species mass (as a proxy for size) indicated that large and/or conspicuous species tend to be targeted by harvesters for the traditional medicine trade. Furthermore, based on cluster analyses for species groups of similar risk, vultures, hornbills, and other large avifauna, such as bustards, are most threatened by selective harvesting and should be prioritised for conservation action.  相似文献   

10.
South Africa is home to approximately 10% of the world's flora, many of which are endemic to the country. A large number of South African genera have been improved for horticultural use and many of these are economically important as cut flowers or ornamentals on international markets. The genus Crocosmia, an attractive member of the family Iridaceae, has potential both as an ornamental plant and for cut flower production, although market potential of the species may be increased by improving the size of the flowers and inflorescence. Polyploidy has been used as a tool in the improvement of ornamental plants and has led to the development of several improved ornamental species. This study established a micropropagation protocol for Crocosmia aurea, using seed as the source material. Tetraploidy was induced by treating seeds with colchicine. These seeds were subsequently germinated and multiplied in vitro using the established protocol. The resulting tetraploid plantlets were successfully hardened-off and used to study the effect of the induced tetraploidy on the plant characteristics. The tetraploid (4n) plants were found to have longer, wider leaves as well as longer inflorescence stems and fewer, but larger, flowers than their diploid (2n) counterparts. These polyploid selections have potential in the ornamental/floriculture trade.  相似文献   

11.
The presence of small knobs/nodules found on the adaxial leaflet surface of some Encephalartos species was investigated in 134 cycad species of nine genera. The knobs, referred to as collicles, were found to be the result of connecting mucilage canal ‘bridges’ over vascular bundles, connecting mucilage canals situated between adjacent parallel vascular bundles. Collicles were found on some Encephalartos species only and not always on all individuals of the same species. The possible taxonomic value of these collicles is discussed.  相似文献   

12.
While the role of various processes in inflammatory-related degenerative disorders is still being researched, many avenues of research have concentrated on the treatment and/or prevention of these disorders. Inflammatory-responses, the cholinergic system and oxidative stress have often been linked to the symptoms prevalent in aged persons and Alzheimer's patients. The current research explored the selective inhibition of cyclooxygenase (COX) enzymes, antioxidant and anti-cholinesterase activities of selected South African orchid extracts, currently traded in herbal markets along the east coast of South Africa. Out of a total of 53 evaluated extracts, significant anti-inflammatory activity was observed in nearly 40% of extracts in the COX-1 assay and 25% of extracts in the COX-2 assay. Overall, the DCM root extract of Ansellia africana was the most potent, the DCM tuber extract of Eulophia hereroensis was the only extract to significantly inhibit both COX enzymes, while all Bulbophyllum scaberulum organic root extracts exhibited COX-2 selective inhibitory activity. Bulbophyllum scaberulum DCM root extract was also the most effective anti-cholinesterase extract, performing better than galanthamine. In the single electron transfer (SET) (2,2′-diphenylpicrylhydrazyl (DPPH) free radical scavenging assay and ferric reducing antioxidant power (FRAP) reaction based assays, E. petersii pseudobulb and A. africana root extracts performed better than other extracts. In the hydrogen atom transfer (HAT) (β-carotene/linoleic acid assay) reaction-based assay, the leaf extract of Tridactyle tridentata and root extracts of Cyrtorchis arcuata and E. hereroensis exhibited the best antioxidant effects. The mutagenicity (Salmonella/microsome assay) was also determined. Organic leaf and root extracts of C. arcuata produced no genotoxic effects in comparison to the other tested species. None of the crude extracts tested demonstrated mutagenic effects using S. typhimurium strain TA98 with metabolic activation. The results obtained in this study validate the use of certain orchid species in South African traditional medicine for inflammation-related degenerative disorders.  相似文献   

13.
Large quantities of plants are traded annually in South Africa's traditional medicine or ‘muthi’ markets. A resource in high demand in the Faraday (Johannesburg) and Warwick (Durban) markets is uMavumbuka, a root holoparasite usually identified as either Hydnora africana Thunb. or Sarcophyte sanguinea Sparrm. subsp. sanguinea. However, rhizomes regularly observed in Faraday between 1994 and 2008 did not resemble either species, thereby suggesting that a third, and undocumented, species was being harvested. This was confirmed when the rhizomes were identified as H. abyssinica A.Br. by an American parasitic plant expert. An ethno-ecological study was initiated to verify its occurrence in selected muthi markets. The study further aimed to investigate the distribution of H. abyssinica through trader interviews, host species localities and some previously misidentified herbarium specimens. The study revealed that H. abyssinica was the only uMavumbuka species present in Faraday and Warwick in 2009. Furthermore, the rhizomes were being harvested in KwaZulu-Natal—an area not previously known to be part of its distribution range. Re-evaluated herbarium vouchers and recent photographs taken in the Kruger National Park have confirmed that H. abyssinica occurs in KwaZulu-Natal, Limpopo, Mpumalanga, Gauteng and Swaziland and hence eastern southern Africa. Fragments of Acacia xanthophloea Benth. roots were identified on 93% of the samples that had host roots attached, and we suspect that H. abyssinica follows the distribution of A. xanthophloea in suitable habitats north from KwaZulu-Natal and adjoining the South African border with Swaziland and Mozambique. Acacia karroo Hayne and A. grandicornuta Gerstner have also been positively identified as host species in South Africa from herbarium records. Plant harvesters in the markets cited the common names of several other species that uMavumbuka “grows under” that may be identified as hosts to H. abyssinica in the future. The collection of specimens in areas identified by the harvesters and in areas of suitable habitat is important to verify the occurrence, distribution and habitat of H. abyssinica in eastern southern Africa.  相似文献   

14.
In 2009, South Africa completed the IUCN Red List assessments of 20,456 indigenous vascular plant taxa. During that process, medicinal plant species (especially those sold in informal muthi markets) were identified so that potential extinction risks posed to these species could be assessed. The present study examines and analyses the recently documented threat statuses of South African ethnomedicinal taxa, including the number of species used, revealing family richness and the degree of endemism, and calculates the Red List Index (RLI) of species survival to measure the relative degree of threat to medicinal species. Approximately 2062 indigenous plant species (10% of the total flora) have been recorded as being used for traditional medicine in South Africa, of which it has been determined that 82 species (0.4% of the total national flora) are threatened with extinction at a national level in the short and medium terms and a further 100 species are of conservation concern (including two species already extinct in the wild). Thirty-two percent of the taxa have been recorded in traditional medicine markets in the provinces of KwaZulu-Natal, Gauteng, Eastern Cape, Mpumalanga and Limpopo. The study also reflects on the challenges associated with Red List evaluations of medicinal species, many of which, based on market reports, are extracted at a seemingly unsustainable rate. In contrast to the majority of species enumerated in the Red List of South African plants, medicinal taxa are often widespread, with large extents of occurrence. Accordingly, the population decline criteria have necessarily been applied to assess threats to their existence, even though accurate figures for numbers of remaining individuals, areas of occupancy, quantities harvested, and regeneration times are often found lacking. Factors leading to susceptibility of plant species to extinction as a result of harvesting pressure are discussed. The current findings reveal a need for greater emphasis on focussed population level research on prioritised medicinal plant species.  相似文献   

15.
The summer‐growing dwarf geophyte Eucomis amaryllidifolia Baker is native to South Africa's Eastern Cape. Following an investigation into genome sizes of all species of Eucomis, the taxon is returned from subspecies to species status, and details of its history, taxonomy and cultivation are given, accompanied by a colour plate.  相似文献   

16.
P.A. Gadek 《Phytochemistry》1982,21(4):889-890
Biflavonoid patterns from ethanolic extracts of the brightly coloured testa of eight species of Cycadales have been determined. Species from the genus Macrozamia are characterized by the occurrence of cupressuflavone- and amentoflavone-based patterns, while the Cycas species contain only amentoflavone-based patterns. The other species from the genera Encephalartos, Lepidozamia, and Zamia contain a very minor or no detectable biflavonoid component. This is the first report of the occurrence of cupressuflavone in the Cycadales.  相似文献   

17.
A group of eight species ofEncephalartos, comprisingE. altensteinii, E. arenarius, E. horridus,E. latifrons, E. lehmannii, E. longifolius, E. princeps, andE. trispinosus, from the Eastern Cape Province of South Africa, was studied by analysis of iso-enzymes, ribosome DNA, and ITS 1 and 2 genes. The reason for this investigation was that the morphology of the vegetative and reproductive parts, though very distinctive in this geographical region, do not correlate, and it was hoped that molecular data would elucidate evolutionary relationships. The three sets of molecular data were found to agree to a remarkable degree. It was concluded that the vegetative morphology was misleading but that the cone characteristics agree with molecular data and provide insight into the interrelationships of these species. Thus,E. princeps was concluded to be relatively remotely related to the vegetatively similarE. lehmannii, andE. arenarius is not at all close toE. latifrons even though the two species are easy to confuse when not in cone.  相似文献   

18.
The global and national Red List status of cycads known from mainlandAfrica are presented in this study. Seventy-four taxa (including five as yetundescribed taxa) occur in Angola, Benin, Central African Republic, DemocraticRepublic of Congo, Ghana, Kenya, Malawi, Mozambique, Nigeria, South Africa,Sudan, Swaziland, Tanzania, Uganda, Zambia and Zimbabwe. South Africa has thehighest richness of cycad taxa (41). Fifty-two of the continent's cycadsare confirmed country endemics, and 59% are globally threatened. One undescribedEncephalartos taxon is categorised as extinct (Malawi) andthree, Encephalartos woodii Sander, E.relictus P.J.H. Hurter and another undescribedEncephalartos taxon (South Africa), are known only frommaterial in cultivation. The nature and extent of threats to cycads appear to bedifferent in the southern African region compared to the rest of the continent,and illegal collection is thought to be the primary factor. Taxa listed as datadeficient primarily occur in war-torn and botanically under-explored areas. Theresults of the Red Lists are interpreted in terms of life-history strategies andthreats. Continental-level conservation efforts are suggested for preservingwild stocks.  相似文献   

19.
The Sungazer (Smaug giganteus) is a threatened lizard species endemic to the Highveld grasslands of South Africa. The species faces risks from habitat loss and fragmentation, and illegal harvesting for traditional medicine and the pet trade. Despite these threats, the current conservation status of the species was poorly validated. We visited 79 Sungazer populations recorded in 1978 to assess population change since the initial surveys, and surveyed an additional 164 sites to better define the distribution and estimate the current population size. We interrogated all known historical trade data of the species. One-third of Sungazer populations have been extirpated over the past 37 years. The distribution includes two allopatric populations, with the smaller Mpumalanga population experiencing a significantly higher decline. The species has an extent of occurrence (EOO) of 34 500 km2, and an area of occupancy (AOO) of 1149 km2. The interpreted distribution is 17 978 km2, and just under 60% remains untransformed grassland. We estimate a population size of 677 000 mature individuals, down 48% from the estimated historical population, prior to commercial agricultural development. A total of 1194 live Sungazers were exported under permit from South Africa between 1985 and 2014, with a significant increase in numbers exported over the last decade. Without any evidence of captive breeding, we believe that these animals are all wild-caught. Based on the AOO, level of decline, fragmentation within the distribution and suspected level of exploitation, we recommend classification of the species as Vulnerable under IUCN Red List Criteria A2acd and B2ab(ii–v). The establishment of a protected area network, genetic research and further investigations into the pet and traditional medicine trades are urgently needed.  相似文献   

20.
Five taxa already in the literature are here removed from Chydorus to their own genus Ephemeroporus, and two new species — E. acanthodes and E. archboldi — are described, with E. acanthodes being designated the type species of the genus. These taxa, plus at least nine undescribed species and others undoubtedly waiting to be sorted out, constitute a tightly circumscribed group of species morphologically. The first two species described — E. barroisi and E. poppei — are nomina dubia for the present, as no specimens exist from the original collections, nor are any available from the type localities or reasonably close thereto. E. hybridus from Brazil has been characterized in greater detail through the availability of specimens from the type series, which has enabled one of the species in the E. hybridus group from North America to be judged conspecific with reasonable certainty. E. tridentatus, from Brazil, has been restored as a valid species, and the highly distinctive E. phintonicus from Sardinia and Algeria constitutes the seventh species in the genus. Chydorus nitidulus and Chydorus tilhoi, which have been suggested to be members of the barroisi complex, are not. What are presently called E. barroisi and E. hybridus, except for E. hybridus, sens. str., each consists of a cluster of species sharing the same number of teeth on the labrum and shell. Because of their wide, distribution, abundance, and frequency of occurrence, especially in South Asia, the species in the E. barroisi group will be especially meaningful to sort out.  相似文献   

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