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1.
从形态学而论,烟杆藓属(Buxbaumia Hedw.)在苔藓植物中是一个独特的类型。该文简要介绍了烟杆藓属的历史和该属在中国的研究状况,以及该属的模式种烟杆藓首次在中国的发现。对烟杆藓在新疆的着生生境及群落状况做了详细介绍, 还就扫描电子显微镜观察烟杆藓的孢蒴、蒴齿和孢子形态、中国烟杆藓属分种检索表及属的系统关系进行观察和探讨。  相似文献   

2.
《Journal of bryology》2013,35(3):209-214
Abstract

The two species of Buxbaumia Hedw. known to occur in Europe were both originally discovered on this continent and were the earliest in the genus (as presently delimited) to be described. Already widely known, Buxbaumia aphylla Hedw., was validated by Johannes Hedwig in 1801, whereas B. viridis (DC.) Moug. & Nestl. was initially described as a variety of B. aphylla by Augustin Pyramus de Candolle in 1815. After two centuries in the bryological literature, these taxa are herein effectively typified. Lectotypes for the names B. aphylla and B. viridis are designated based on original herbarium sheets from the Hedwig-Schwägrichen and De Candolle collections in G.  相似文献   

3.
4.
ABSTRACT

In this paper, lymnaeid snails collected from 107 localities in Hokkaido, Japan were examined for infection by Fasciola larvae. DNA sequences from the snails were analysed phylogenetically based on their mitochondrial cytochrome c oxidase (COI) gene. Based on shell morphology, the snails were identified as Galba truncatula, Radix auricularia, and Austropeplea ollula and were divided into distinct clades in the COI tree. No Fasciola larvae were detected in any of the collected snails. The 58 haplotypes of Galba truncatula which were found in Hokkaido included five detected previously in snails infected with Fasciola larvae, and constituted a closely related haplogroup (Gt-c1), suggesting that Gt-c1 snails would be susceptible to Fasciola sp. The Gt14 haplotype snails were considered to be Lymnaea schirazensis, an intermediate host of F. hepatica. The COI haplotypes of A. ollula belonged to a single clade, and were considered conspecific, whereas those of R. auricularia constituted three genetically distinct haplogroups, each of which was possibly a distinct species. This study suggests that morphologically-identified lymnaeid snails possibly include additional species. Further study of these snails is required to clarify their susceptibility to Fasciola sp.  相似文献   

5.
《Journal of bryology》2013,35(4):743-746
Abstract

The spore wall ornamentation of B. indusiata (B. viridis) and B. aphylla has been characterized by SEM and is similar in both species. On the basis of the observations made, the authors define the spores of the two species as catalept and not atreme as reported in earlier literature.  相似文献   

6.
The leafless spurgeEuphorbia aphylla (Euphorbiaceae), an endemic species restricted to several of the Canary Islands where it inhabits coastal and arid localities, expresses Crassulacean Acid Metabolism (CAM) when it is subjected to summer drought. A flexible CAM is consistent with the general ecology of the species. It is the only member of sect.Tirucalli native to the Canary Islands and is at the north-western edge of the section's biogeographical range. The other members of the section have a paleotropic distribution and are found throughout Africa. Many of them are regarded as obligate CAM plants, includingE. tirucalli which was used as a comparison in ecophysiological experiments examining the response ofE. aphylla to drought and temperature.  相似文献   

7.
We carried out translocations of three rare plants that inhabit mineral islands in the marshy Biebrza Valley in order to create alternative populations and facilitate connectivity between existing subpopulations. The species chosen were Iris aphylla and two orchids: Cypripedium calceolus and Cephalanthera rubra. Thirty soil monoliths with vegetative orchid plants or parts of I. aphylla rhizomes were dug out and transplanted to three different sites on new mineral islands (half in 2012 and half in 2013). Prior to translocation, we measured soil moisture and pH and took phytosociological characteristics in 68 potential recipient sites for orchids and 15 for I. aphylla. Then, we monitored the number of shoots for 4 years and retrospectively conducted principal component analysis (PCA) in order to compare the similarity of donor sites and chosen recipient sites. Three years after transplantation we found new C. calceolus populations in good condition, I. aphylla populations in moderate, while C. rubra transplants emerged only in the first and second season. All newly established populations of C. calceolus and I. aphylla survived. In the case of the first species, fruiting was observed in two populations, while a marked increase in shoot number was observed in one population. The most successful C. calceolus translocation site was also the most similar to the donor sites according to PCA.  相似文献   

8.
Tamarix aphylla is an evergreen tree that has invaded the drawdown zone of Lake Mead, a large reservoir on the Lower Colorado River. We performed competition experiments between T. aphylla and T. ramosissima, and between T. aphylla and the native tree Salix gooddingii. Root:shoot ratios and biomass were higher in S. gooddingii than both Tamarix species, and T. ramosissima grew taller than T. aphylla and S. gooddingii when treatments with single plants and no competition were compared. Tamarix aphylla outcompeted the native S. gooddingii, but had competitive abilities that were slightly inferior to T. ramosissima. The competitive abilities of T. aphylla may and help explain why this species is not as widespread as its congeners, although because of T. aphylla's larger size, the species may be as serious a threat to native riparian ecosystems as T. ramosissima. These results indicate that management actions should be taken to ensure that T. aphylla does not further invade riparian ecosystems in the southwestern United States.  相似文献   

9.
Nineteen microsatellite markers were developed from Tetratheca paynterae ssp. paynterae, a rare and endangered, leafless, perennial shrub. Twelve loci were polymorphic in T. paynterae ssp. paynterae with two to 14 alleles per locus and mean expected heterozygosity of 0.62. Primer pairs were tested on four other Tetratheca species from ironstone ranges in southern Western Australia. Ten loci were polymorphic in T. paynterae ssp. cremnobata and T. aphylla ssp. aphylla, three in T. harperi and four in T. erubescens. The level of polymorphism was adequate for studies of genetic structure and mating systems in three of the five taxa.  相似文献   

10.
The Pyrola picta species complex of western North America comprises four species (P. picta, P. dentata, P. aphylla and P. crypta) that grow sympatrically in some parts of their collective ranges, have remarkably similar flowers and share pollinators. These species do not exhibit the genetic signatures typical of random or heterospecific mating, but instead show genetic divergence patterns indicating that they maintain surprising levels of reproductive isolation. To better understand how species boundaries are maintained, the current study uses statistical ordination analyses to determine whether species isolation across shared geographical ranges might be achieved through subtle differences in floral characters among species. The possible contribution of differences in flowering phenology (e.g. temporal reproductive isolation) to reproductive isolation was also evaluated for the small subset of populations in which two or more species occur in direct sympatry. Among species in the P. picta complex, there are both phylogenetic and geographical trends in some floral characteristics, whereas other characters do not covary with either geography or species identity. In several sympatric populations, differences in flowering phenology among species suggest that timing plays a major role in non‐random (i.e. mainly conspecific) mating. The conclusions of this study are that reproductive isolation in the P. picta species complex is reinforced by differences in the timing of floral maturation and the morphologies of androecium and floral display characters. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 00 , 000–000.  相似文献   

11.
Summary The fungus Aspergillus terreus Thorn var. terreus isolated from an Ecuador soil sample was cultured in liquid and solid media and yielded three main metabolites identified as terreic acid (1), butyrolactone I (2) and lovastatin (3). The natural products as well as three synthetic butyrolactone I derivatives were assessed for antimicrobial activity against Gram-positive and Gram-negative bacteria and fungi as well as for seed germination and seedling growth. Furthermore, the compounds were assessed as inhibitors towards the enzymes acetylcholinesterase, β-glucosidase, and β-glucuronidase. Terreic acid, butyrolactone I, butyrolactone 4′,4′′-diacetate (2.1), and 3′-(3-methylbutyl)-butyrolactone II (2.2) were active towards the phytopathogenic bacteria Erwinia carotovora with IC50 of 5 and 4–18 μg/ml, respectively. Under the same experimental conditions, the IC50 of streptomycin was 1.9 μg/ml. 3′-(3-Methylbutyl)-butyrolactone II was moderately active against Pseudomonas syringae and Botrytis cinerea with IC50 of 21μg/ml and MIC of 15.6 μg/ml, respectively. Butyrolactone I also inhibited germination of the dicot Lactuca sativa with an IC50 of 5 × 10−5 M. The IC50 of reference herbicide acetochlor was 1 × 10−5 M. The effect of 2.2 and 2.3, known as butyrolactone III on Panicum millaceum germination and growth was stronger than that of 2 and 2.1. Reduction of the double bond in the isoprenyl side chain of butyrolactone I increased the antibacterial effect against E. carotovora as well as acetylation. To our best knowledge, this is the first report on the antibacterial effect of butyrolactone derivatives towards Erwinia carotovora and the phytopathogenic fungus Botrytis cinerea. The butyrolactone I derivative 2.2 presented a moderate inhibitory effect against the enzyme acetylcholinesterase with an IC50 of 47 μg/ml. Under the same experimental conditions, the reference inhibitor galanthamine had an IC50 of 3 μg/ml.  相似文献   

12.
Spatial patterns and associations of plant species are important for revealing how species interact with each other and with the environment, and hence have important implications for the understanding of species interaction and underlying ecological processes with apparent patterns in temperate desert vegetation. In this paper, the function g (r) was used to characterize the spatial patterns and associations of four dominant woody species in three 1-ha desert plant plots in the desert–oasis ecotone of South Junggar Basin, NW China. The complete spatial randomness null model showed four species exhibited significant aggregations at small scales (<20 m). Anabasis aphylla and Nitraria roborowskii, Haloxylon ammodendron and Reaumuria songarica were spatially positive associations at small scales with the independent null model, while A. aphylla and H. ammodendron, A. aphylla and R. songarica, R. songarica and N. roborowskii species pairs exhibited negative associations at small or moderate scales (20–60 m) in our study. The random labeling null model showed that dead standing plants of A. aphylla were largely determined by the combined effects of intra- and interspecific competition. In addition, the results also indicated that the two main factors of habitat heterogeneity and sandy desertification play important roles in determining spatial distribution patterns and associations of woody species in the desert–oasis ecotone of South Junggar Basin. Thus, the differences of species features in spatial patterns and associations should be paid more attention when planning afforestation and developing conservation strategies.  相似文献   

13.
Many viral oncogenes encode protein~yrosine kinase activities. However, importantin vivo substrates of these enzymes have yet to be identified. Recently, type I topoisomerases were shown to bein vitro substrates for two tyrosine kinases. Following tyrosine phosphorylation, topoisomerase I activity was reduced 10-fold (Tse-Dinhet al. Nature 312:785–786, 1984). To determine whether topoisomerase I activity was modulated by tyrosine phosphorylationin vivo, we have measured topoisomerase I activity in nuclear lysates prepared from both normal fibroblasts and cells transformed by two different viral oncogenes (v-abl, v-src). Under a variety of experimental conditions, we have found no evidence to support the notion that type I topoisomerase activity is modulated by tyrosine phosphorylationin vivo.  相似文献   

14.

Background  

Tamarix aphylla is a halophyte growing in soils rich in NaCl. Leaves of Tamarix aphylla develop numerous salt glands, which initiate, secrete NaCl, become senescent and eventually die, as part of a programmed process. Dead glands are replaced by new ones, so that only active glands exist on the leaves. Most importantly, these glands remove excess NaCl from the tissues, which protects against hyperosmotic phenomena.  相似文献   

15.
Summary

Buxbaumia aphylla is a rare and enigmatic moss in Britain where it is found regularly and in sizeable populations only on colliery debris (‘bings’) in central Scotland. Its habitat preferences and ecology are described from a range of sites. It has persisted in quantity in several localities for over 20 years, but in other apparently suitable sites it is absent. Destruction and landscaping of bings are seen as the major threat to the species in Scotland.  相似文献   

16.
The Korean species of Illiberis Walker are revised. A total of 10 species are recognized, including four species new to Korea: I. rotundata Jordan, I. psychina (OberthÜr), I. consimilis Leech, and I. hyalina (Staudinger). The identities of I. cybele Leech and I. assimilis Jordan, the two ambiguously defined Korean species, are reconfirmed with the examination of type specimens and additional materials. Photos of the adults and type materials are provided, and male and female genitalia of each species are illustrated. Biology and distribution for each species are briefly discussed with the larval host records from Korea.  相似文献   

17.
 Intron-2 of the Oryza sativa CatA catalase gene is similar in nucleotide sequence to p-SINE1, a retroposon, and seems to have been added to the ancestral genome of rice. To examine when the p-SINE1-like intron was inserted into CatA during the evolutionary divergence of Oryza species, and to elucidate the evolutionary relationships among Oryza species using the sequence of the intron as a marker, we performed polymerase chain reaction (PCR) analyses of 32 accessions of 17 Oryza species with various genome types. Agarose-gel electrophoresis of the PCR products revealed that all the Oryza species with an AA genome have the CatA homolog with the intron, whereas other Oryza species have the CatA homolog without the intron. These results indicate that intron-2 of CatA is a good marker for distinguishing species with an AA genome among Oryza species. Sequencing of the PCR products showed that all the introns are similar to p-SINE1, though with slight variations in length. We also performed PCR analyses using four accessions of three species in genera related to Oryza, and found that there is an intron in the CatA homolog of Leersia perrieri. On the other hand, the CatA homolog of Porteresia coarctata has no intron. Sequence data showed that the L. perrieri homolog has a p-SINE1-like intron similar to that in Oryza species with an AA genome. These results suggest that the p-SINE1-like intron was already present in the common ancestor of Oryza and L. perrieri and was then lost in the ancestors of P. coarctata and of the Oryza species other than those with an AA genome. The phylogenetic tree of Oryza species with an AA genome based on the nucleotide sequences of the introns leads us to propose that Oryza species with an AA genome evolved from an ancestor of Oryza longistaminata. Received: 29 August 1998 / Accepted: 2 November 1998  相似文献   

18.
Four species of the Drosophila virilis group, D. montana, D. littoralis, D. lummei, and D. ezoana, occur sympatrically in several locations in northern Europe. Courtship interactions between the flies of the three first-mentioned species were observed at malt baits in Kemi, northern Finland, to find out how the flies of different species recognize conspecific individuals and how interspecific courtships differ from intraspecific ones in the wild. Intraspecific courtships (including females of different reproductive stages) and interspecific courtships were also videotaped and analyzed in laboratory. In the wild the males courted both conspecific and allospecific females, even though the species varied in how much the males were attracted to females of different species. Interspecific courtships usually broke off when the male touched the female or when the male and/or the female vibrated his/her wings, producing acoustic cues. In the laboratory males courted conspecific females irrespective of the reproductive stage of the female, even though the courtships directed toward immature and fertilized females usually included only orienting and touching (no licking and singing). D. littoralis, and very rarely D. montana and D. lummei, males courted also allospecific females. In the few interspecific courtships between these three species, where the male proceeded to singing, females responded to male singing by vibrating their wings. This ended the courtship. It is suggested that both the chemical cues affecting female attractivity and the acoustic signals of males and females, which are produced by wing vibration, function in maintaining sexual isolation between these three species.  相似文献   

19.
Abstract

Critical notes on the flora of Italy. II. The Minuartia verna group. The following paper contains a re-examination of the Minuartia verna–complex in Italy based on a revision of herbarium-specimens and observations in nature. The author proposes to divide this polymorphic species into 4 subspecies. Two of them (subsp. verna and subsp. collina) are largely corresponding to the opinion of earlier authors. The subsp. attica is also represented in the flora of Southern Italy, but Italian populations are slightly different from those of Greece (which must be regarded as typical). The subsp. grandiflora living in a small area in Sicily, which was incompletely known, is described and its relations to the other subspecies are discussed.  相似文献   

20.
The taxonomic relationship between the 2 marine blue-green algae,Calothrix scopulorum andC. crustacea, which are considered to be conspecific by some authors, is discussed based on the statistical investigation of morphology with field and culture materials and on the phenological investigation. The presence or absence of intercalary heterocyst in the filament cannot be always used as a clear taxonomic character to distinguish the 2 species, judging from the result of culture experiment. However, it is confirmed that there are morphological differences between the two in the length of filament, the diameters of filament, trichome, hair, heterocyst and hormogon and the seriation of heterocyst in the filament, and that there are also ecological differences between the two in the color of plant, the tidal level of growth, the period of growth and the season of hormogon formation. From these facts it is concluded thatC. scopulorum andC. crustacea should be treated as separate species.  相似文献   

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