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1.
A taxonomic reevaluation of two little-knownBrimeura taxa,B. fontqueri (Pau)Speta andB. duvigneaudii (L. Llorens)Rosselló et al., has been made.Brimeura fontqueri, described from the Iberian peninsula, has been put into synonymy ofB. amethystina (L.)Salisb., since it could not be distinguished on morphological, anatomical or cytogenetic grounds.Brimeura duvigneaudii, from the Balearic Islands, is closely related toB. amethystina and has 2n=28 chromosomes. It differs from the latter by its naked bulbs lacking dark cataphylls, and its narrower leaves and whitish corollas. Accessory chromosomes are reported for the first time in the genus. Karyological instability (with chromosome numbers ranging from 2n=28 to 42) is reported for a population ofB. fastigiata (Viv.)Chouard. A key to the recognized taxa ofBrimeura is provided.  相似文献   

2.
Cypripedioideae (Orchidaceae) have been the subject of numerous taxonomic treatments with conflicting interpretations of relationships among the five genera and the 150–170 species. We have produced nuclear ribosomal ITS nucleotide sequences for nearly 100 slipper orchid species and used parsimony analysis to investigate their relationships. Our results demonstrate that each genus, as currently circumscribed, is monophyletic (Mexipedium andSelenipedium being represented by a single taxon). LikerbcL data, ITS sequences placeMexipedium sister toPhragmipedium. Relationships at the sectional level inPaphiopedilum are largely as described byCribb. However, the division ofPaphiopedilum into subgg.Brachypetalum andPaphiopedilum is not supported; subg.Brachypetalum is paraphyletic to subg.Paphiopedilum. Phragmipedium species are divided into the same three major clades as in the taxonomic scheme ofMcCook. The plicate-leaved genera,Cypripedium andSelenipedium, are successive sister groups to the rest of the subfamily, confirming generally held opinions that they display plesiomorphic characters compared to the conduplicate-leaved genera. A survey of karyotypes in the context of the ITS tree reveals a general trend toward increased chromosome number, probably brought about by centric fission. These data also accord with a previously suggested biogeographic hypothesis of a widespread Northern Hemisphere distribution, followed by range fragmentation due to Miocene cooling.  相似文献   

3.
Twenty-two chironomid species were found in Lake Shabla. Five species (Chironomus bonus, Dicrotendipes lobiger, Kiefferulus tendipediformis, Cricotopus suspiciosus and Cricotopus sp.) are new for Bulgaria. Their karytopes are described for the first time.Cytogenetic studies of two closely related chironomid species, Glyptotendipes glaucus and G. pallens, show that in one area of sympatry (Lake Shabla, Bulgaria) about 2.5% of the naturally occuring individuals are hybrids. In most cases, in this hybrid, 1st, IInd and IIIrd chromosomes correspond fully to the chromosomes of G. glaucus. The IVth chromosome is a hybrid, with one homologue of the species G. glaucus; the other homologue is derived from G. pallens. Introgressive hybridization is of particular importance to the production of these combinations. Despite hybridization, natural selection appears to maintain the essential integrity of each separate gene pool.  相似文献   

4.
Summary Eight monocentric fungi are reported in two provisionally identified species ofRhizosolenia from sea-water. Only two species are assigned specific names. These areRhizophydium planktonicum Canter andR. fragilariae Canter. A fungus with depressed-globose sporangia is included as a form ofR. fragilariae. Two unidentified species ofChytridium are reported. A fungus tentatively assigned toZygorhizidium and a form provisionally assigned toPetersenia are also reported and described insofar as their characteristics are known.  相似文献   

5.
Summary InSolanum lycopersicum pachytene chromosomes the gradient in chromomere size, originating on both sides of the kinetochore, reveals the following characteristics: 1. a relatively abrupt decrease in size of the large chromomeres, 2. the gradient is related to arm length in 9 of the 12 chromosomes, 3. the gradient is particularly irregular in the short arm of the nucleolar chromosome and in the long arm is not conspicuous, 4. chromosome 6 shows an abrupt interruption in the gradient close to the kinetochore. Salvia viridis andZea mays chromosomes represent intermediate conditions between species with well defined and species without gradients. InSalvia the intermediate condition is manifested by the presence of a very large chromomere on each side of the kinetochore followed by very small chromomeres. In two chromosomes the intermediate condition is particularly apparent. In these chromosomes two chromomeres of intermediate size are present in the proximal region of the long arm. The nucleolar organizing arm has also an irregular pattern in this species.Maize has a less distinct gradient than tomato in all its chromosomes. Chromosomes 3, 4, 5 and 8 are those where the gradient is the least sharp. The nucleolar organizing arm of chromosome 6 has also an irregular pattern.In a translocation between chromosomes 5 and 6 of maize, a segment composed of very small chromomeres from the distal region of 5 which was moved to the right of the kinetochore of chromosome 6, did not change appreciably its phenotype after ten years of cultivation. During the period of cultivation a selection was made for plants where the original phenotype was preserved so that this result cannot be considered as demonstrating an absence of change in chromomere phenotype with changed position.InDrosophila andChironomus salivary gland chromosomes where chromomeres are large, and no selection has been carried out with such a purpose, the pattern and nucleic acid content of the bands is known to change when rearrangements occur within the chromosome.Supported by a grant from the Swedish Natural Science Research Council toA. Lima-De-Faria. This work was partly carried out at the Department of Botany, University of Illinois, U.S.A. during a visit to this department byA. Lima-De-Faria.P. Sarvella's collaboration in this work was done during her stay at the University of Lund.  相似文献   

6.
The karyotypes ofP. juncea (Elymus junceus) andP. huashanica (both outbreeders) were investigated by Feulgen-staining and by C-, N-, and Agbanding, based on a single plant in cach case. Both species have 2n=2x=14 and large chromosomes, possibly a generic character. The karyotype ofP. juncea has 8 metacentrics and 6 SAT-chromosomes with minute, heterochromatic satellites while that ofP. huashanica has 9 metacentrics and 5 SAT-chromosomes only, 2 of which with small, heterochromatic satellites. The C-banding patterns ofP. juncea chromosomes comprise from one to five, mostly small, bands at distal, and terminal positions, while those ofP. huashanica chromosomes are characterized by large telomeric bands in most arms. Banding patterns and chromosome morphology allow identification of the homologues of the seven chromosome pairs inP. juncea, but of two pairs inP. huashanica only. The patterns of both taxa are polymorphic, supporting that both taxa are outbreeders. The karyotypic characters suggest thatP. juncea is more closely related toP. fragilis than either is toP. huashanica. N-banding stains weakly. Silver nitrate staining demonstrates that nucleolus organizers of both species have different nucleolus forming capacities. The presence of micronucleoli suggests that both species have an extra unidentified chromosome with nucleolus forming capacity.  相似文献   

7.
Chromosome numbers are determined from 37 populations attributed to 22 taxa of JapaneseArisaema. Of them, chromosome numbers ofA. limbatum var.conspicuum (2n=26),A. minus (2n=26),A. nambae (2n=28) andA. seppikoense (2n=26) are determined for the first time. New chromosome numbers, 2n=26, are reported forA. aequinoctiale, A. limbatum, A. stenophyllum, A. undulatifolium andA. yoshinagae. Three modes of basic chromosome numbers,x=14,x=13 andx=12, occur in JapaneseArisaema. Precise karyotypic comparisons of 20 taxa reveal that taxa withx=14 andx=13 share 26 major chromosome arms and have an obvious chromosomal relationship. One of two submeta-centric chromosomes inx=13 corresponds to two telo-centric chromosomes inx=14. InA. ternatipartitum with 2n=6x=72, ten out of 12 basic chromosomes are the most similar in size and arm ratio with larger ten chromosomes ofA. ringens among JapaneseArisaema examined. A basic chromosome number ofx=14 is the commonest in the genusArisaema and the remaining basic chromosome numbers,x=13 andx=12, seem to be derived through dysploidal reduction by translocating large segments of major arm of telo-centric chromosome onto other minor arm of telo-centric followed by loss of the remainings including a centromere, and by loss of two telo-centrics fromx=14, respectively. Some systematic problems of JapaneseArisaema are discussed based on new cytological data.Arisaema hatizyoense, A. minus andA. nambae are accepted as independent species.  相似文献   

8.
T. Raghunath 《Mycopathologia》1966,30(3-4):209-215
Summary 1. A new species ofAlternaria isolated from the diseased plants ofCarum copticum L.Peucedanum graveolens Benth. &Hook f. andFoeniculum vulgare Mill. is described and compared with other species affecting Umbelliferae.2. TheCoriandrum isolate described by the writer asAlternaria poonensis Raghunath is a shy sporulator in artificial culture with long beaked muriform spores formed singly at the end of comparatively short conidiophores.3. The isolate from the other three host plantsCarum copticum L.,Peucedanum graveolens Benth. &Hook f. andFoeniculum vulgare Mill. is named asAlternaria umbellifericola sp. nov. and is a profusely sporulating species, forming long chains of spores with rudimentary beak.4. TheCoriandrum isolate (Alternaria poonensis) has a narrower temperature range (25–30° C) than theCarum isolate (20–35° C) for optimum sporulation.5. TheCoriandrum isolate is pathogenic toCarum but not toDaucus carota L.6. TheCarum isolate is pathogenic toDaucus carota but does not infectCoriandrum sativum L.7. TheCoriandrum isolate has a wider host range among the Umbelliferae than theCarum isolate.Part of the M.Sc. thesis submitted to the Poona University, 1964.  相似文献   

9.
Liparis indiraii spec. nova from India is close toL. alata A. Rich. andL. atropurpurea Lindl.  相似文献   

10.
Summary This paper deals with two new species ofOidiopsis, O. convolvuli andO. euphorbiae, on two new hostsConvolvulus arvensis L. andEuphorbia microphylla Heyne. It also makes two new reports of its imperfect stage onTagetes erecta L. andAbutilon indicum L.  相似文献   

11.
J. Voegelé 《BioControl》1964,9(1):119-122
Summary The Author describes from Morocco a new species ofAsolcus which is closely related to the sibling speciesA. basalis Wollaston andA. nigribasalis Voegelé. The species is namedA. bennisi and parasitizes in nature the eggs ofGraphosoma lineata L. The separation ofA. bennisi from the species of thebasalis group is based on biological tests and on a characteristic pigmentation of the parasitized host eggs reared under optimal laboratory conditions.   相似文献   

12.
Results obtained from crossing experiments betweenP. somniferum subsp.somniferum (2n = 22) and subsp.setigerum (2n = 44),P. glaucum (2n = 14) andP. gracile (2n = 14) and from the observation of meiotic chromosome pairing in the various hybrids obtained do not provide straightforward evidence for the hypothesis thatP. somniferum originated as a triploid hybrid between taxa similar toP. glaucum andP. gracile (Kadereit 1986a, b).—On the one hand, the pattern of crossability found reflects the closer similarity of subsp.somniferum toP. glaucum and of subsp.setigerum toP. gracile, which was interpreted as segregation of parental characters, and the high frequency of 2n = 28 chromosomes among F2-progeny from the hybrid subsp.somniferum × subsp.setigerum (2n = 33) might reveal n = 7 as the base number also ofP. somniferum. On the other hand, however, the general difficulty of obtaining hybrids, and the low incidence of bivalent formation in their meiosis, probably indicating a lack of chromosome homology between the different species, do not fit the above hypothesis.—These results are in marked contrast to the morphological similarity between the three species involved.  相似文献   

13.
Eocryphops andPlagiolaria are revised and a new species,E. albertii, is described from the Eifelian of Morocco.“Trimerocephalus” cyclophthalmus Walther, 1907, a species long assigned toEocryphops, is regarded as a junior subjective synonym of the type species ofPlagiolaria, Pl, plagiophthalma. Eocryphops originated in the evolutionary lineage leading toPhacops (s.str.), whereasPlagiolaria was probably derived fromLochkovella. Although they have been linked with the Late Devonian group of small-eyed and blind phacopids includingCryphops and its relatives. neitherEocryphops norPlagiolaria is ancestral to these forms. Confirmed occurrences ofEocryphops andPlagiolaria are from regions that were situated on the North Gondwana margin or on plates associated with this margin.  相似文献   

14.
The genetic relationships ofAechmea mexicana, A. lueddemanniana, A. macvaughii andA. tuitensis were investigated using starch gel electrophoresis. Eight enzyme systems encoded by ten putative gene loci were resolved in seventeen populations.Nei's (1978) genetic distances were obtained from allelic frequencies and used with UPGMA algorithm. Results indicate that some populations belonging to different species display genetic similarities closer to each other than to some conspecific populations. Our results do not support the proposed genusUrsulaea (Read & Baensch 1994), sinceA. tuitensis was closer toA. lueddemanniana andA. mexicana than toA. macvaughii.  相似文献   

15.
Summary Two species of fungi,Tryblidiella rufula (Spreng.)Sacc. andTrabutia butleri Theiss &Syd. have been figured and described for the first time from Orissa. The former was found growing on dead twigs ofCitrus aurantifolia (Christm.)Swingle and onCitrus sp. and the latter on living leaves ofFicus religiosa L.  相似文献   

16.
Density patterns ofLipiniella arenicola andChironomus muratensis were studied in Lake Wolderwijd (The Netherlands) using geostatistics, and compared with patterns of depth and silt contents of the sediment.L. arenicola was restricted to shallow (depth <1 m), sandy silt (silt content <5%), wind-exposed sediments.Ch. muratensis occurred all over the lake, but the highest densities were found in the sheltered silty North-West corner. Gut analyses of IV-instar larvae from the Ventjagers flats (Haringvliet, Lower Rhine-Meuse) showed thatL. arenicola fed by selectively grazing on benthic algae,Ch. muratensis by filtering and non-selective grazing, andCh. nudiventris by non-selective grazing. In the laboratory, behavioural responses to reduced oxygen concentrations were tested with the impedance conversion technique.L. arenicola was more sensitive to low oxygen concentrations (<3 mg l–1) than bothChironomus species. It is argued that the differences in resistance to hypoxia and feeding behaviour are in accordance with the differences in distribution patterns. The restriction ofL. arenicola to the pure sand habitats is not attributable to an especially high sensitivity to low dissolved oxygen concentrations alone. Several behavioural adaptations enableL. arenicola larvae to live in the shallow, wind-exposed pure-sand habitats: the ability to select food items, tube strength, and site selection of ovipositing females or planktonic larvae.  相似文献   

17.
The evolution and taxonomic relationships in theTriticeae are discussed with the view to highlight aspects of this agronomically important group of plants, which may be of interest to molecular biology. Some of these aspects are addressed in more detail in adjoining papers in which specific genomic loci have been examined at the DNA sequence or isozyme level. Aspects discussed include the systematics and geographic distribution of theTriticeae species, isozyme and chromosome pairing studies on some of the species as well as more recent developments in DNA analyses. A survey of the systematics of theTriticeae indicated that the genomic system ofLöve is probably the most useful starting point for interpreting molecular data even though the system has many problems from a taxonomic point of view. The geographical distribution ofTriticeae species, using both published and unpublished data, suggested that information of this type taken together with the theory of continental drift provides a broad time-span for considering data from DNA sequence studies. The significance, and modes of analyses, of isozyme studies were assessed because they often provide valuable characters in determining relationships between species. The main character underlyingLöve's andDewey's analyses of theTriticeae, namely chromosome pairing, is discussed with particular reference to isozyme studies to show that in some cases, such as species ofHordeum sensu lato, consistent relationships are obtained. Finally, new developments in understanding chromosome structure are considered in relation to the above variables in the taxonomy and evolution of theTriticeae.  相似文献   

18.
Investigations on interspecific crossability in 8Cucumis species (2n = 24) and chromosome pairing and pollen fertility of their hybrids from 15 combinations have been utilized for tracing the phylogenetic relationships among these taxa and factors responsible for their differentiation. A collective evaluation of data suggests that there are three broad groups of species, one of the spiny fruited interfertile species, whose hybrids show varying degree of chromosome associations and low to high pollen fertility; the second of species with non-spiny fruits, which are completely incompatible with the former but weakly compatible with the cultivated species,C. melo L. to produce partly developed seeds, and the third group ofC. metuliferus E. Mey. exSchrad. andC. melo and its different botanical varieties. The species with spiny fruits can be further divided based on karyomorphological similarities and/or on relative genomic affinity, indicated by chromosome pairing and hybrid pollen fertility.Cytogenetics inCucumis III.  相似文献   

19.
New species of Alternaria from Marathwada (India)   总被引:1,自引:0,他引:1  
Summary The paper deals with two new species ofAlternaria, Alternaria nyctanthi onNyctanthes arbortristis Linn. andAlternaria tropaeoli onTropaeolum majus L.  相似文献   

20.
Genomic in situ hybridization offers a powerful tool for investigating genome organisation and evolution of taxa known, or suspected, to be allopolyploids. The question of the diploid progenitors of cultivated peanut (Arachis hypogaea, 2n=4x=40) has been the subject of numerous studies at cytogenetical, cytochemical, biochemical and molecular levels, but no definitive conclusions have been reached. The biotinylated total genomic DNA from potential diploidArachis species were separately hybridized in situ to root tip chromosomes ofA. hypogaea and wild speciesA. monticola (2n=4x=40) without or mixed with an excess of unlabelled DNA from the species not used as a probe. Among the range of different species combinations used, the strong and uniform signals given by labelledA. ipaensis DNA when hybridized toA. hypogaea andA. monticola in combination with unlabelledA. villosa DNA indicates that overall molecular composition of twenty chromosomes ofA. hypogaea andA. monticola is very similar toA. ipaensis chromosomes. ProbingA. hypogaea andA. monticola chromosomes with labelled genomic DNA fromA. villosa mixed with unlabelled DNA fromA. ipaensis likewise labelled strongly and uniformly the other twenty chromosomes. BarringA. ipaensis, all the diploidArachis species presently investigated had characteristic centromeric bands in the twenty chromosomes within the complement indicating a clear division ofA. ipaensis from other species. InA. hypogaea andA. monticola only twenty chromosomes showed centromeric bands. These results (i) confirm the allopolyploid nature ofA. hypogaea andA. monticola, (ii) strongly support the view that wildA. monticola and cultivatedA. hypogaea are very closely related, and (iii) indicate thatA. villosa andA. ipaensis are the diploid wild progenitors of the tetraploid species studied. The present results also reveal that the nucleolus organizing region (NOR) originating fromA. villosa alone is expressed in the two tetraploid species.  相似文献   

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