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1.
Summary  The original collections of Salix species described by Pallas are discussed. Eight names validated by Pallas and one by Nasarov are typified. The use of six currently accepted names, S. arbutifolia Pall., S. arctica Pall., S. berberifolia Pall., S. caspica Pall., S. divaricata Pall. and S. rhamnifolia Pall., is confirmed. Salix serotina Pall. retains its place as a synonym of S. viminalis L. Salix gmelinii Pall. is resurrected and proposed as the correct name for the taxon previously known as S. dasyclados Wimm. S. burjatica Nasarow and S. jacutica Nasarow, the old synonyms of S. dasyclados, therefore are now also synonyms of S. gmelinii. A new combination S. rosmarinifolia L. subsp. sibirica is proposed.  相似文献   

2.
Summary. Exine ontogeny is studied in five taxa of the family Zygophyllaceae sensu lato (Peganum harmala L., Zygophyllum album L., Fagonia cretica L., Tribulus terrestris L., and Nitraria retusa [Forsk.] Asch.). In the beginning of the tetrad stage, the plasmalemma is attached to the callose wall, except in T. terrestris, where it describes crests and hollows. The primexine matrix is fibrillar, bilayered in T. terrestris and unilayered in the other taxa. In all species except P. harmala, the procolumellae are heterogeneous with clear zones and they become compact later. In T. terrestris, they are built on the crests. In Z. album and T. terrestris, a primordial nexinic lamella is set up. It is tripartite with a white line seen at some levels; on its external leaflet, the foot layer is observed, and on its internal leaflet, there is the endexine with numerous lamellae. This white line disappears often in the mature exine. In T. terrestris, there is a thick nexine that is coarsely lamellate inside. In the aperture zone, the columellae are lacking, the tectum and the foot layer get thinner; they unite and form the apertural membrane with the external part of the endexine. There is a granulolamellar endexinic zone well developed in P. harmala, whereas it is threelayered and weakly developed in T. terrestris. Correspondence and reprints: Laboratoire de Botanique Fondamentale et Appliquée, Faculté des Sciences, Université de Tunis El Manar, Campus universitaire, 1060 Tunis, Tunisia.  相似文献   

3.
Fasciola hepatica is a trematode that causes zoonosis mainly in cattle and sheep and occasionally in humans. Fascioliasis has been reported in Korea; however, determining F. hepatica infection in snails has not been done recently. Thus, using PCR, we evaluated the prevalence of F. hepatica infection in snails at 4 large water-dropwort fields. Among 349 examined snails, F. hepatica-specific internal transcribed space 1 (ITS-1) and/or ITS-2 markers were detected in 12 snails and confirmed using sequence analysis. Morphologically, 213 of 349 collected snails were dextral shelled, which is the same aperture as the lymnaeid snail, the vectorial host for F. hepatica. Among the 12 F. hepatica-infected snails, 6 were known first intermediate hosts in Korea (Lymnaea viridis and L. ollula) and the remaining 6 (Lymnaea sp.) were potentially a new first intermediate host in Korea. It has been shown that the overall prevalence of the snails contaminated with F. hepatica in water-dropwort fields was 3.4%; however, the prevalence varied among the fields. This is the first study to estimate the prevalence of F. hepatica infection using the vectorial capacity of the snails in Korea.  相似文献   

4.
A new method of studying genetic factors in phenotypical variability of rodents is applied for the cycling population of water vole (Arvicola terrestris L.) in Northern Baraba. The components of the maximum additive heritability are found via the correlations “parent-offspring” in vivarium population. The interannual phenotypical variability of natural rodent populations is studied in the space of these components. It is shown that radical genetic restructuring in the population takes place in the phase of low density. The genetic specificity of different cycles of vole population dynamics is confirmed as well. The changes of common animals sizes associated with population dynamics are determined by heterozygosity effects.  相似文献   

5.
Life-cycle and foraging patterns of native Bombus terrestris populations were investigated at two sites in the Mediterranean region of Turkey, Phassalis (0 – 100 m above sea level [a.s.l.]) and Termessos (500 – 700 m a.s.l.). Bumble-bee activity was recorded during standard bee walks from November 2003 until the end of October 2004, each site being visited three times every month during the one-year period. The yearly dynamics of flight, the flowering plant species visited, and the visitation frequencies of these plants were recorded during every bee walk at both sites. There were considerable differences between the two populations with regard to the dates when the queens emerged from diapause (the emerging season), the timing of the appearance of sexuals (young queens and males), and the total number of plant species visited. Bombus terrestris queens emerged from diapause in November-December at the Phassalis site (coastal area) and in February-March at the Termessos site. The queens aestivated at the Phassalis site, whereas they hibernated at the Termessos site. Only one generation per year was produced at each site. The duration of the queens’ diapause lasted 5 – 8 months and length of the life cycle 190 – 215 days. Native B. terrestris populations were noted to forage on 47 flowering plant species from 20 families (10 at the Phassalis site and 40 at the Termessos site) during the study period. Two of the plant species (Arbutus unedo L. and Vitex agnus-castus L.) have long flowering periods and play a crucial role in the life cycle of native B. terrestris populations. The emergence of queens at the aestivation site was synchronized with the flowering of Arbutus unedo L., while the emergence of sexuals coincided with the flowering of Vitex agnus-castus L. at both sites. Received 30 May 2007; revised 5 December 2007; accepted 8 January 2008.  相似文献   

6.
1. Increasing urbanisation is often cited as a cause of declining biodiversity, but for bumblebees there is evidence that urban populations of some species such as Bombus terrestris L. may be more dense than those found in agricultural landscapes, perhaps because gardens provide plentiful floral resources and nesting opportunities. 2. Here we examine the influence of urbanisation on the prevalence of the main protozoan parasites of bumblebees in west central Scotland. We would expect transmission rates and prevalence of parasites to be higher in high density host populations, all else being equal. 3. Workers of two bee species, B. terrestris and B. pascuorum, were sampled over a 45‐day period in mid to late summer, and parasites were detected in faeces and via dissection. A comparison of the two methods suggests that faecal sampling is considerably less sensitive than dissection, failing to detect infection in 27.8%, 55.1%, and 80% of cases of infection with the parasites Crithidia bombi, Nosema bombi, and Apicystis bombi, respectively. 4. For all three parasites, broad patterns of prevalence were similar, with prevalence tending to increase with urbanisation in B. terrestris but not in B. pascuorum. The different patterns of seasonal prevalence in the two bee species suggest that intraspecific transmission is more important that interspecific transmission. 5. Our observation of greater parasite prevalence among B. terrestris in urban compared with rural areas suggests that urban habitats may present greater opportunities for parasite transmission. Greater bee densities in urban areas may be the driving factor; however, further study is still needed. For example, differences in disease prevalence between habitats could be driven by differences in the types and abundance of flowers that are available, or in exposure to environmental stressors.  相似文献   

7.
Conservation tillage combined with crop-residue mulching is increasingly important to meet soil protection targets. Concurrently, the health risk of soil-borne pathogenic fungi like Fusarium species, which produce deoxynivalenol (DON) as their major mycotoxin, is increasing. The detritivorous earthworm species Lumbricus terrestris takes part in the efficient degradation of Fusarium-infected and DON-contaminated wheat straw. Against this background, a laboratory study was conducted to quantify by means of ELISA technique the uptake of DON and its possible absorption and accumulation in tissue by L. terrestris in the short-term (5 weeks) and long-term (11 weeks). The DON concentrations in L. terrestris of the Fusarium-infected treatment were significantly different in the order of gut tissue > body wall > gut content at both dates with a decline in the long-term. The DON concentrations in the tissues decreased by an order of magnitude of weeks to months.  相似文献   

8.
Earthworm survival in oil contaminated soil   总被引:4,自引:0,他引:4  
Earthworms are an important component of the soil biota and their response to oil pollution needs to be better understood. Laboratory investigations were undertaken to determine the concentrations of crude oil in soil that leads to death of Lumbricus terrestris and Eisenia fetida and to determine the propensity of L. terrestris to move away from contaminated soil. Clemville sandy clay loam was amended to contain maximum oil contents of 1.5 – 2.5% depending on the particular experiment. Additionally, the ability of L. terrestristo survive in bioremediated oil-contaminated soil was evaluated. An oil content of 0.5% was not harmful to survival of earthworms for 7 d but an oil concentration of 1.5% reduced survival to less than 40%. Bioremediated soil containing 1.2% oil did not reduce survival of L. terrestrisduring 10 d. Survival of L. terrestrisin unweathered oil was improved when free movement between contaminated and uncontaminated soil was possible. Casts of earthworms exposed to oil-containing soil contained 0.2% total petroleum hydrocarbons. An allowable regulatory level of 1% oil contamination in soil may not allow for survival of earthworms.  相似文献   

9.
A repetitive DNA sequence used as a specific probe for Fasciola hepatica infections in snails was examined in F. hepatica and Fasciola gigantica (36 individuals) specimens from five continents. The degree of intraspecific identity ranged from 79 to 99% in F. hepatica and from 93 to 99% in F. gigantica. The interspecific identity ranged from 81 to 100%, confirming the suggestion that the DNA probe sequence could be used worldwide as an epidemiological tool for the examination of the intermediate host snail in fasciolosis. Differentiation between F. hepatica and F. gigantica infections in snails was not possible using the probe.  相似文献   

10.
Owing to climate change, the global resurgence of vector‐borne infectious diseases has emerged as a critical public health issue. Orientia tsutsugamushi is the etiological agent of tsutsugamushi disease (scrub typhus) a mite‐borne acute febrile disease occurring in the Asia‐Pacific region. We investigated the prevalence of tsutsugamushi disease transmitted by chigger mite vectors living on rodents. Using sticky‐type chigger traps for three months during 2016–2018, 1,057 chigger mites were collected (chigger mite index, 1.31) from four locations in the Hwaseong‐si area of Gyeonggi‐do, Republic of Korea. Five species distributed among three genera were identified. In addition, 94 rodents were captured (collection rate: 7.83%) using Sherman live traps over the course of three months (April, October, and November) during 2016–2017. Three rodent species were captured and identified and the striped field mouse (Apodemus agrarius) was the dominant rodent host species in the surveyed area. A total of 10,469 ectoparasitic chigger mites were recovered from the 94 rodents, from which 13 species distributed among four genera were identified. Of the 5,250 chigger mites examined, Leptotrombidium pallidum was most abundant (n = 2,558), followed by L. orientale, L. scutellare, L. zetum, Euschoengastia koreaensis, L. subintermedium, and Neotrombicula tamiyai. Of the examined chigger mites, no groups recovered from rodent hosts tested positive for O. tsutsugamushi. This study provides fundamental regional information on vector‐borne disease data collection in the Hwaseong‐si area, Gyeonggi‐do, and will further contribute to formulating disease control and prevention strategies.  相似文献   

11.
The buff-tailed bumblebee, Bombus terrestris, was introduced into Japan in 1991 and is now widely established in Hokkaido, northern Japan. To characterize environmental factors affecting the naturalization of B. terrestris, we examined the relationship between vegetation, land use, and bumblebee fauna at various sites in Hokkaido. Increase of human-modified environments and reduced area of forest were associated with B. terrestris inhabitation. Although agricultural fields provide a huge expanse of land for B. terrestris naturalization, environmental instability (human impacts or weather factors) sometimes leads to local population extinctions. Urban and residential areas may suffer less fluctuation and provide suitable environments for B. terrestris naturalization though the total area is rather small. Presence of the both types of human-modified environments is likely to lead the introduction of B. terrestris into new areas in Hokkaido, northern Japan.  相似文献   

12.
Zusammenfassung Im Dehydrations-Experiment versuchen Lumbriciden den permanenten Wasserverlust durch Gegenregulation zu kompensieren. Dieser Prozeß wird durch funktionell gekoppelte aminerge und peptiderge Neuronenkomplexe zentralnervös kontrolliert. Durch Elektrokoagulation bestimmter Areale des Ober- und Unterschlundganglions vonLumbricus terrestris L., Durchtrennung von Bahnverbindungen (Konnektive und Kommissuren) und Injektion von Reserpin wurden mindestens fünf verschiedene zentrale Regelglieder gefunden, die sich gegenseitig fördernd oder hemmend beeinflussen. Das übergeordnete Zentrum der Dehydrations-Kontrolle liegt im ArealA III des Oberschlundganglions, in dem zwischen ependymähnlichen Fasergliaformationen kettenförmig angeordnete Zilienquerschnitte beobachtet wurden. Eine Funktion dieser Zilien als zentralgelegene Rezeptor-organe des Regelsystems wird erwogen.
The central nervous control of dehydration inLumbricus terrestris L.
Summary Lumbricidae try to compensate for the permanent water loss during experimentally induced dehydration. InLumbricus terrestris L. this process is controlled by functionally coupled aminergic and peptidergic neurons of the central nervous system. It was shown (1) by electrocoagulation of well defined areas of the supra- and sub-oesophageal ganglion, (2) by transsection of the circumoesophageal connectives and commissures, and (3) by injection of reserpine into the coelomic cavity of the third and fourth segment, that there may be five different centers controlling water loss and compensatory processes acting after the loss. The greatest water loss was observed after destruction of areaA III of the suprao-esophageal ganglion. This region was built up of ependyma-like glial cells and rows of cilia of unknown origin. The possible role of these cilia as central receptor sites in the control mechanism of water balance inLumbricus terrestris L. is discussed.
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.  相似文献   

13.
Subgenus Cerasus species are useful genetic resources for cherry breeding programs. A total of 17 morphological traits together with 19 random amplified polymorphic DNA (RAPD) primers were used to study 39 accessions including 34 wild Cerasus subgenus genotypes belonging to Prunus avium L., P. cerasus L., P. mahaleb L., P. microcarpa Boiss., P. incana Pall., and P. brachypetala Boiss. species, along with an unknown wild Cerasus sample, two advanced cherry cultivars (‘Lambert’ and ‘Bulgar’), and two rootstocks (‘Colt’ and ‘Gisela 6’). Genotypes were separated into different groups according to their species and collection sites using cluster analysis performed by Ward’s clustering method based on morphological data. Nineteen RAPD primers from 60 screened produced 304 polymorphic reproducible bands (98.15% polymorphism). According to the similarity matrix, the lowest similarity was obtained between P. avium and P. microcarpa samples. A dendrogram was prepared by the unweighted pair-group method with arithmetic average (UPGMA), and the accessions were separated according to their species and geographic origin. In both morphological and molecular results, the advanced cultivars and rootstocks were separated from wild genotypes, and the unknown genotype was grouped with P. mahaleb accessions. Grouping by morphological characteristics was compared with the results of RAPD analysis, with no significant correlations between morphological and molecular data being found. This is the first report of molecular (RAPD) genetic diversity study in wild Cerasus subgenus genotypes from Iran, and the results demonstrate the high potential of RAPD analysis for discrimination of Cerasus subgenus genotypes.  相似文献   

14.
The South American lulo (Solanum quitoense Lam.) is a crop plant of the Andes of Ecuador and Colombia, pollinated by South American bumblebees, such as, Bombus atratus Franklin. The cultivation of lulo outside of its native range, for example in European glasshouses, requires the presence of efficient pollinators to enable high fruit set and yield. Until now, the suitability of Bombus terrestris L., native to Europe and commonly used in agriculture, has been untested for this purpose. In this study, the pollen‐collecting behaviour of B. terrestris when visiting lulo flowers was investigated. It was shown that B. terrestris adopted the lulo as a pollen source, and on average visited three flowers per minute, had five buzzing events per stay and foraged for 15 s on a single flower, independently of the previous number of visits and level of bruising to the anthers. The pollination efficiency of five different treatments was evaluated: (i) exclusion of bees, (ii) single and (iii) multiple visits of B. terrestris, (iv) self‐ and (v) cross‐pollination by hand. The results clearly demonstrated that, for fruit set, pollination is crucial. It was also found that lulo flowers can be successfully self‐pollinated, but give 25% fewer fruit set compared with pollination via multiple bumblebee visits, or cross‐pollination by hand. Fruit set, seed set and fruit size were as high with pollination by B. terrestris as with cross‐pollination by hand, indicating that this bumblebee is an appropriate pollinator for lulo. However, B. terrestris was conspicuously less effective when a flower was visited only once. Therefore, when growing lulos commercially, multiple bumblebee visits should be encouraged, but it is likely that the behaviour of B. terrestris would ensure this anyway. Our results indicate that B. terrestris is a suitable and efficient pollinator for the production of lulo fruits.  相似文献   

15.
Paranosema (Nosema) locustae Canning has persisted in grasshopper populations in the Inner Mongolia Rangeland since spore treatment was applied in 1993. In the treatment year, a 58.32–71.43% reduction of grasshoppers was recorded and 59.26–80.36% of surviving grasshoppers of various species were infected. In the years following application, prevalence of P. locustae varied from 13.65% to 60.71%, demonstrating that P. locustae remains in grasshopper populations for many years. Infection prevalence was more than 60.00% for Dasyhippus barbipes (F.-W.), Bryodema luctuosum luctuosoma (Stoll) and Angaracris barabensis (Pall.) in 1993 but was very variable, ranging from 20.00% to 60.71% over the subsequent nine years. Disease prevalence was 43.72–60.71% in 1993 and 1994 for Oedaleus asiaticus B.-Bienko and Myrmeleotettix palpalis (Zub.) but gradually declined to approximately 20%, where it remained. Persistence of P. locustae in grasshopper populations may be important in keeping densities below economic thresholds for a number of years after application. Handling Editor: Helen Roy.  相似文献   

16.
To explore the possibility of an effectively long-term preservation of the germplasm of the HR lines of medicinal plant Astragalus membranaceus, Gentiana macrophylla Pall., and Eruca sativa Mill., both cold storage and cryopreservation approaches were attempted and compared. After 5-month cold storage on half strength Murashige and Skoog (1962) (1/2 MS) agar medium (AM), up to 82.9, 75.7, and 100% of the A. membranaceus, G. macrophylla and E. sativa hairy roots (HRs) recovered growth, respectively. The survival rates of A. membranaceus and G. macrophylla HRs significantly decreased, whereas that of E. sativa HR was unchanged with the addition of increased levels of exogenous abscisic acid (ABA) during cold storage. Using the encapsulation–vitrification (EV) method for cryopreservation, the G. macrophylla HRs died, whereas up to 6 and 73% of the A. membranaceus and E. sativa HRs survived, respectively. The HR lines evaluated with both methods showed no significant differences in morphology and growth rate compared with controls that were not subjected to preservation methods. These results suggest that cold storage is a more suitable alternative for the HR lines of the three studied plant species and that specificity of plant species have profound effects on the effectiveness of preservation.  相似文献   

17.
Abstract. The decline of deciduous woodland populations of Anemone hepatica L. in southern Sweden is documented and possible causes are discussed. The study was based on (1) re‐investigations of 6.25 km2 grid‐squares first studied in 1938–1970, (2) distribution of A. hepatica in woodland sites with well‐known soil chemical properties and (3) a detailed study over 12 consecutive years into the relationships between biological characteristics of the species (number of individuals, vegetative development, flowering frequency) and environmental variables (temperature, precipitation), soil chemistry and time. There was a close relationship between soil acidity (pH, solubility of Al3+) and both distribution and biological characteristics. The biological variables declined significantly over time but were not related to climatic variability. Increasing soil acidity and Al3+ solubility are concluded to be the main factors responsible for the decline of A. hepatica in S. Swedish deciduous woodlands.  相似文献   

18.
19.
Th effect of fenvalerate 20% EC (a synthetic pyrethroid) on the growth of two ectomycorrhizal fungi, Thelephora terrestris and Laccaria laccata, was studied in vitro. In the case of T. terrestris, mycelial growth was promoted at lower concentrations of the insecticide but inhibited at higher concentrations; mycelial growth of L. laccata decreased with increase in concentration. The effect of the insecticide at three concentrations (0.25, 0.5, 1.5 ppm) was also studied on ectomycorrhizal formation in 4-month-old seedlings of Pinus patula in nursery trials. At lower concentrations the insecticide had no significant effect on mycorrhizal formation.  相似文献   

20.
An exotic bumblebee species, Bombus terrestris, has colonized in Japan and becomes dominant in some local communities. We examined the effects of land use and bumblebee abundance on the number and body size of bumblebees collected using window traps in a lowland area in the southern Ishikari district, Hokkaido. In 2004, we collected 922 bumblebees of six species using 70 traps at 17 sites. A statistical model fitted to the data demonstrated that dispersion from commercial B. terrestris colonies used in greenhouses positively affected the number of B. terrestris caught by each trap. This exotic species was abundant in sites where paddy fields were prevalent, but three native species, B. hypocrita, B. ardens, and B. diversus, were abundant in sites where farms and woodlands were widespread. The local abundance of B. terrestris was not associated negatively with the number and body size of native bumblebees. Thus, we did not find any competitive interactions between exotic and native bumblebees although habitat conditions seem to be common determinants of the bumblebee populations. A morphological analysis showed that B. terrestris had intermediate tongue length between B. hypocrita and B. ardens.  相似文献   

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