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1.
Morphological comparisons are made from the study of 64 specimens belonging to the following species:Squalus acanihias, S. blainvillei, S. megalops andS. acutirostris. The results suggest conspecificity betweenS. acutipinnis andS. megalops. The differences betweenS. blainvillei andS. megalops in the E-Atlantic are stressed. The Indo-Pacific species calledS. blainvillei by Chen et al. (1979) is regarded in this paper as probably an undescribed species. Some consideration on the status of several nominal species and the species grouping withinSqualus are also made.  相似文献   

2.
雅鲁藏布江高寒河谷流动沙地适生植物种筛选和恢复效果   总被引:5,自引:0,他引:5  
沈渭寿  李海东  林乃峰  张涛  袁磊  孙明  孙俊  纪迪 《生态学报》2012,32(17):5609-5618
通过4a的人工模拟飞播试验研究(2008—2011年),观测了北方优良沙生植物种和西藏乡土沙生植物种在雅鲁藏布江中游高寒河谷流动沙地上的出苗、保存、生长和繁殖情况,筛选和确定了西藏高寒流动沙地人工模拟飞播的适生植物种。结果表明:籽蒿、花棒、沙拐枣、杨柴和砂生槐在高寒河谷流动沙地的适应性较好。籽蒿在播后第2年便有花序和种子出现,花棒和沙拐枣在第3年开花结实,籽蒿、花棒和沙拐枣均能完成生活史。籽蒿的再繁殖能力较弱,花棒和沙拐枣的再繁殖能力较强。不同类型沙丘的形态特征对人工模拟飞播效果影响较大,最适宜型(第Ⅰ类)流动沙地的人工模拟飞播效果最好,植被盖度达35%;较适宜型(第Ⅱ类)流动沙地的效果较好,植被盖度达30%;不适宜型(第Ⅲ类)流动沙地的效果最差,植被盖度尚不足10%;基本适宜型(第Ⅳ类)流动沙地的效果较差,但采用沿等高线人工脚踩回头撒播法,植被盖度可达20%。不同沙丘部位的人工模拟飞播效果差异明显。  相似文献   

3.
Quantitatively evaluated C-banding karyograms and further observations on karyotype structure are presented forScilla persica, 7 species of theScilla hohenackeri group, andPuschkinia scilloides. Within theS. hohenackeri group very diverse and species-specific banding patterns are found. On the basis of karyology,S. bisotunensis andS. furseorum should be closely grouped together, whileS. persica andPuschkinia scilloides appear quite isolated.  相似文献   

4.
DNA base composition of species of the genusSaccharomyces   总被引:1,自引:0,他引:1  
DNA base compositions (GC content) ofSaccharomyces species are reported and discussed. Several amendments of the four groups given by van der Walt are suggested, viz. the transfer ofS. kluyveri to group 1, and ofS. eupagycus, S. cidri, S. montanus, S. microellipsodes andS. florentinus to group 2. The synonomy ofS. amurcae andS. cidri is suggested. The DNA base compositions revealed two possible pairs of sibling species:S. elegans andS. bailii, with a difference in GC content of 4.1%;S. dairensis andS. servazzii with a difference in GC content of ca. 3%.S. mrakii had a GC content of 47.3–48.5% the highest encountered in this genus and similar to that ofKluyveromyces thermotolerans.  相似文献   

5.
The life cycle of the moth,Meskea horor Dyar and its host specificity toSida acuta andS. rhombifolia were investigated. Moths emerge early in the morning and are usually inactive during the day. Feeding by the adults in the field was not observed. However, those in the laboratory fed on flowers ofS. acuta, S. rhombifolia andHibiscus sabdariffa, and drank water or dilute honey solution. Eggs are mainly laid on the underside of leaves. Larvae ofM. horor form galls in the stems ofS. acuta andS. rhombifolia which retard plant growth and flowering. Pupation occurs within the gall. The development time from egg to adult was 192 days and the adults lived for 11 to 14 days. Forty-eight plant species were tested to determine the host range ofM. horor. Adults emerged from seven species of plants in the family Malvaceae and larvae formed galls but died before pupating on a further 17 species.M. horor is considered to have too broad a host range to be used as a biological control agent forS. acuta andS. rhombifolia.  相似文献   

6.
Sandra Knapp 《Brittonia》1986,38(3):273-301
Fourteen new species ofSolanum sectionGeminata are described and illustrated. Eight of these,S. erosomarginatum, S. foetens, S. lasiocladum, S. lucens, S. ombrophilum, S. tanysepalum, S. tenuiflagellatum, andS. turgidum are from Venezuela.Solanum cucullatum andS. bellum are from Ecuador,S. abitaguense from Ecuador and northeastern Peru,S. amnicola andS. yanamonense from eastern Peru, andS. mapiricum from eastern Bolivia. Relationships of each of the species to others in its geographical area are discussed. Chromosome numbers are reported for ten of these new species.  相似文献   

7.
Sagittaria graminea and allies as herein interpreted include a natural morphological complex of seven species and two varieties:S. graminea (including vars.chapmanii, weatherbiana, andgraminea), S. platyphylla, S. rigida, S. teres, S. isoetiformis, S. cristata, andS. fasciculata. This group is characterized by nonsagittate leaves, pubescent dilated filaments, and reflexed sepals ; all taxa are monoecious. Taxonomic conclusions are based on field and herbarium studies and cross-compatibility experiments.  相似文献   

8.
1. Australian crab spiders exploit the plant–pollinator mutualism by reflecting UV light that attracts pollinators to the flowers where they sit. However, spider UV reflection seems to vary broadly within and between individuals and species, and we are still lacking any comparative studies of prey and/or predator behaviour towards spider colour variation. 2. Here we looked at the natural variation in the coloration of two species of Australian crab spiders, Thomisus spectabilis and Diaea evanida, collected from the field. Furthermore, we examined how two species of native bees responded to variation in colour contrast generated by spiders sitting in flowers compared with vacant flowers. We used data from a bee choice experiment with D. evanida spiders and Trigona carbonaria bees and also published data on T. spectabilis spiders and Austroplebeia australis bees. 3. In the field both spider species were always achromatically (from a distance) undetectable but chromatically (at closer range) detectable for bees. Experimentally, we showed species‐specific differences in bee behaviour towards particular spider colour variation: T. carbonaria bees did not show any preference for any colour contrasts generated by D. evanida spiders but A. australis bees were more likely to reject flowers with more contrasting T. spectabilis spiders. 4. Our study suggests that some of the spider colour variation that we encounter in the field may be partly explained by the spider's ability to adjust the reflectance properties of its colour relative to the behaviour of the species of prey available.  相似文献   

9.
New Sutneriids from Eastern Africa (Ethiopia, Djibouti and Tanzania) are described and their phylogenetic relations discussed; one species is new, three are mentioned first time from Eastern Africa. During the taxonomic studies it became evident that a revision of the old european speciesS. cyclodorsata andS. eumela should be included as those species have been interpreted in different ways since the last century. Therefore it was inevitable to restudy the types and further material. Forms not belonging to these species as defined by the types have been described asS. hoelderi andS. lorioli nom. nov.  相似文献   

10.
Billie L. Turner 《Brittonia》1985,37(1):117-120
Two new species ofSenecio,S. sundbergii andS. neogibsonii, belonging to the sectionPalmatinervii are described, illustrated, and compared to their nearest relatives,S. aschenbornianus andS. lanicaulis.  相似文献   

11.
Scymnodalatias albicauda sp. nov. is described from two specimens taken at high latitudes (45°S and 49°S). It is distinguished fromS. sherwoodi, only known species of the genus, by having white markings on the caudal fin, the second dorsal posterior tip almost reaching the upper caudal fin, shorter snout and head, smaller eye and larger fins. Relationships ofScymnodalatias to the generaScymnodon, Centroscymnus, andZameus are discussed, based chiefly on dermal denticle structure.Scymnodalatias andZameus uniquely share transverse ridges on their dermal denticles, and on this character they are treated as sister-groups. Comments on the above genera,Z. squamulosus and some species ofScymnodon are made to clarify their systematic status. As a result, it is proposed thatScymnodon includesichiharai, macracanthus, plunketi, andringens, thatCentroscymnus includescoelolepis, crepidater, crypt acanthus, andowstonii, and thatZameus includessquamulosus.  相似文献   

12.
William R. Buck 《Brittonia》1983,35(4):327-330
Three new tropical American species ofSematophyllum are described with relatively broad leaves and short upper leaf cells:S. cubense, S. cataractae, andS. oedophysidium. The Central AmericaS. apaloblastum andS. barnesii are new combinations.Sematophyllum galipense, S. amnigenum, andS. cochleatum are briefly discussed.  相似文献   

13.
J. L. Castner 《BioControl》1984,29(3):323-329
Larra bicolor F. wasps successfully parasitized and developed on 5 species ofScapteriscus mole cricket hosts:S. abbreviatus Scudder,S. didactylus (Latreille),S. imitatus Nickle & Castner,S. vicinus Scudder, andS. acletus Rehn & Hebard. Examinations of the mole crickets 10–14 and 20–24 days post-parasitization revealed large differences among host species in the frequency of survival of the developing parasites. The percentages of successful development were:S. abbreviatus=90 %,S. imitatus=87 %,S. acletus=79 %,S. vicinus=51 %, andS. didactylus=18 %. Statistical analysis showed that the percentage of successful parasite development observed onS. didactylus was significantly different from all other species tested. No significant difference was found among the other 4 species.L. bicolor wasps were unsuccessful in parasitizing 90 % of theNeocurtilla hexadactyla (Perty) mole crickets offered, due to a sticky, viscous fluid they excreted when attacked.  相似文献   

14.
Ginseng is a well-known medicinal plant that has been used as an anti-aging agent for many years in East Asia. In the genusPanax, only three species,P. ginseng (Oriental ginseng),P. quinquefolius (American ginseng) andP. notoginseng (Chinese ginseng), are currently considered to be important medicinal herbs. Despite the increase in their breeding value, molecular cytogenetic information on the species is not available. To analyze the genomic relationships among thePanax species, FISH (fluorescencein situ hybridization) and GISH (genomicin situ hybridization) techniques were applied. FISH analysis revealed that the 45S and 5S rRNA genes ofP. notoginseng (2n=2x=24) andP. ginseng (2n=4x=48) cluster on a single locus on different chromosomes, whileP. quinquefolius (2n=4x=48),P. japonicus (2n=4x=48), and Korean wild ginseng (2n =4x= 48) had one locus of the 45S rRNA gene and two loci of the 5S rRNA gene, respectively. GISH analysis using genomic DNA as a probe detected strong cross-hybridization of genomes betweenP. ginseng andP. quinquefolius. GISH analysis of other species showed weak or no distinct signals on the chromosomes. Our data revealed thatP. ginseng andP. quinquefolius showed the highest degree of homology, indicating that these species diverged in most recent years.  相似文献   

15.
The chronospeciesSclerocephalus bavaricus andSclerocephalus haeuseri, with the chronosubspeciesS. h. haeuseri andS. h. jeckenbachensis n. ssp., are redescribed based on material from the lower Rotliegend of the Saar-Nahe region (southern Germany). For the first time numerous features of the skull and postcranial skeleton as wellas the ontogenetic development of the skull are documented. The evolution of these species is discussed.  相似文献   

16.
17.
Three species of lepidopterous larvae were collected fromAmaranthus hybridus L. growing in field corn during 1975 and 1976 at Hastings, Florida.Spodoptera exigua (Hubner) was the predominant species in May.Spodoptera eridania (Cramer) was predominant in June andHerpetogramma bipunctalis (F.) in July and August. Nine native species of parasites, representing theBraconidae, Eulophidae, Ichneumonidae andTachinidae, emerged from these larvae.Meteorus autographae Muesebeck emerged from bothS. exigua andS. eridania. TheTachinidae, Winthemia rufopicta (Bigot),Eucelatori rubentis (Coquillett) andLespensia sp., emerged from mixtures ofS. exigua andS. eridania. Apanteles marginiventris (Cresson),Temelucha sp., andChelonus texanus Cresson emerged from bothS. exigua andH. bipunctalis larvae, andEuplectrus platyhypenae Howard andOphion sp. emerged fromS. eridania. All the species of parasites from the lepidopterous larvae that feed onAmaranthus hybridus are also reported as parasites ofS. frugiperda, a serious pest of corn. Therefore these larvae onA. hybridus may be a source of the parasites found attackingS. frugiperda.  相似文献   

18.
Thirteen species of blue-eyed grasses had been described for the Pacific Northwest prior to this study. Contemporary taxonomic treatments vary; some authors recognize several of the taxa as valid species, others recognize only one highly variable, widely distributed species. Work has been directed to achieve an understanding of the biological integrity of all previously described species within the northwest. Living plants from natural populations were utilized in controlled artificial hybridization experiments, analysis of breeding systems, and cytological investigations. Hybrids of intraand interspecific crosses were examined for pollen fertility, and investigated cytologically for meiotic behavior. Eight genetically compatible groups are indicated from these experiments. Additional information gained from cytological analysis, breeding systems, ecology, distribution, and morphological studies substantiates the recognition of each genetically compatible group at the specific level, including the new species,S. hitchcockii, from southern Oregon. The following taxa are recognized for the Pacific Northwest: tetraploids (n = 16)S. bellum S. Wats.,S. halophilum Greene,S. septentrionale E. P. Bicknell; octoploids (n = 32)S. idahoense E. P. Bicknell (including the vars.segetum,macounii, andoccidentale), andS. hitchcockii D. Henderson; duodecaploids (n = 48)S. idahoense E. P. Bicknell var.idahoense, S. littorale Greene,S. montanum Greene, andS. sarmentosum Suksd. ex Greene.  相似文献   

19.
Chromosome number determinations were made from 407 wild or transplanted individuals and seedlings representing 65 taxa and hybrids inEuthamia andSolidago. The following are first reports:Euthamia remota, 2n=9II;Solidago leavenworthii, 2n=54;S. mollis, 2n=36;S. mollis var.angustata, 2n=36;S. rigida var.glabrata, 2n=9II;S. sempervirens var.azorica, 2n=9II; andS. sparsiflora, 2n=54. Most species have been sampled only a few times or are consistently of one cytotype. Sufficient counts have been made to indicate some general patterns of cytotype distribution in the following species complexes:S. gigantea, S. canadensis, S. flexicaulis, S. rugosa, andS. uliginosa.  相似文献   

20.
George W. Argus 《Brittonia》1984,36(3):328-329
In 1788 Walter described three species ofSalix inFlora Caroliniana. HisSalix pentandra is the same asS. caroliniana, andS. alpina andS. occidentalis are the same asS. tristis Aiton (1789).Salix alpina is a later homonym ofS. alpina Scopoli (1722), and must be rejected, butS. occidentalis is the earliest legitimate name forS. tristis and takes precedence.  相似文献   

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