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1.
Nod factors (Lipo-chitooligosaccharides, or LCOs) act as bacteria-to-plant signal molecules that modulate early events of the Bradyrhizobium-soybean symbiosis. It is known that low root zone temperature inhibits the early stages of this symbiosis; however, the effect of low soil temperature on bacteria-to-plant signaling is largely uninvestigated. We evaluated the effect of low growth temperatures on the production kinetics of Nod factor (LCO) by B. japonicum. Two strains of B. japonicum, 532C and USDA110, were tested for ability to synthesize Nod Bj-V (C(18:1), MeFuc) at three growth temperatures (15, 17 and 28 degrees C). The greatest amounts of the major Nod factor, Nod Bj-V (C(18:1), MeFuc), were produced at 28 degrees C for both strains. At 17 and 15 degrees C, the Nod factor production efficiency, per cell, of B. japonicum 532C and USDA110 was markedly decreased with the lowest Nod factor concentration per cell occurring at 15 degrees C. Strain 532C was more efficient at Nod factor production per cell than strain USDA 110 at all growth temperatures. The biological activity of the extracted Nod factor was unaffected by culture temperature. This study constitutes the first demonstration of reduced Nod factor production efficiency (per cell production) under reduced temperatures, suggesting another way that lower temperatures inhibit establishment of the soybean N(2) fixing symbiosis.  相似文献   

2.
This revision describes, illustrates and documents morphological variation inDoniophyton (Compositae, Barnadesioideae), restricted to Argentina and Chile. Two species are recognized,D. anomalum andD. weddellii (sp. nova), possessing distinct morphological and chromosomal features, elevational tolerances, and nearly allopatric distributions.Doniophyton weddellii occurs primarily in central to northern Andean Chile and Argentina from 1900–4000 m a. s. l.;D. anomalum is found principally in centralwestern Argentina and south into Patagonia at 0–1800 m a. s. l. Close relationship exists withChuquiraga of subfam.Barnadesioideae. It is hypothesized thatDoniophyton evolved out ofChuquiraga in the high central Andes between Chile and Argentina. It is suggested thatD. weddellii differentiated first, correlating with an aneuploid chromosomal decrease from n = 27 (inChuquiraga) to n = 25. Further evolution and chromosomal decrease to n = 24 resulted inD. anomalum, with accompanying migration into southern Andes and Patagonia. Nomenclatural changes result from examination of protologues and type specimens:Doniophyton anomalum replaces the commonly used nameD. patagonicum, and a new species,D. weddellii, is described for the taxon masquerading under the routinely used superfluous nameD. andicola. This paper is dedicated with admiration and respect to emer. Univ.-Prof. DrFriedrich Ehrendorfer, one of the world's outstanding plant systematists, and a leading scientist and administrator of the Institute of Botany of the University of Vienna  相似文献   

3.
The two generaPlectranthus andIsodon are compared and found to be very dissimilar.Isodon ist considered to be misplaced inOcimeae subtribePlectranthinae and apparently is more closely related to subtribeHyptidinae. The disjunct genusRabdosiella is compared to these two genera and regarded to be polyphyletic. The AfricanR. calycina (Benth.)Codd is returned toPlectranthus and calledP. calycinus Benth., while the AsianR. ternifolia (D. Don)Codd is placed inIsodon sect.Pyramidium and calledI. ternifolius (D. Don)Kudo.  相似文献   

4.
A new unicellular species of the genusChrysosphaerella (Chrysophyceae) was found in fresh-water ponds in Switzerland, Japan, and the U.S.A. It is described asC. solitaria. The genus is divided into two subgenera:Chrysosphaerella, comprising the colonial species, andPseudochrysosphaerella, the unicellular ones.  相似文献   

5.
Pairings of monokaryon cultures representingOmphalotus illudens (eastern North America),O. nidiformis (southeastern Australia),O. olearius (southern Europe),O. olivascens (North American Pacific coast), andO. subilludens (southern North America) showed widely variable compatibility patterns.Omphalotus olearius ×O. subilludens ×O. olivascens showed high compatibility, whileO. illudens was significantly less compatible with all other taxa. Isolates ofOmphalotus nidiformis represented an almost genetically isolated biological species. The role of partial compatibility in nomenclatural ranking is discussed.  相似文献   

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7.
In an investigation of the phenology of the chironomid species of Lake Hald, Denmark, a very late flight activity (September–November) of the univoltine speciesProcladius choreus (Mg.) was observed. Among observations of the phenological patterns of univoltine chironomids inhabiting lakes of the Baltic type in Denmark, the phenological pattern ofProcladius choreus stands alone (JÓNSSON, 1987; LARSEN, 1991). Further two species of the genusProcladius Skuse,viz. Procladius crassinervis (Zett) andProcladius signatus (Zett), were found in the investigation and the phenological pattern of the three congeneric species was clearly allochronic, withProcladius crassinervis flying in spring,Procladius signatus flying in summer andProcladius choreus flying in autumn.  相似文献   

8.
A taxonomic study of the largely Mexican genusCarminatia is rendered. It is comprised of three closely related species:C. tenuiflora, C. recondita andC. anomala spec. nova. Illustrations, dot maps, keys to species and complete synonymy are presented.  相似文献   

9.
Neodiaptomus schmackeri and related species are redescribed. The synonymy of this species with N. strigilipes and N. handeli is discussed.  相似文献   

10.
James C. Zech 《Brittonia》1999,51(4):415-421
Flavonoid chemistry of the genusMulinum and selected Mulineae taxa was studied. Both flavones and flavonols were identified as C- and O-glycosides. AllMulinum species contain 6,8-di-C-glycosyl chrysoeriol (flavone) and, with the exception of one, quercetin (flavonol). The presence of both flavones and flavonols in this genus weakens previous generalizations that the mulineae contain only flavonols and are primitive compared to other Apiaceae tribes. Based on the selected taxa studied,Azorella appears to differ from bothMulinum andGymnophyton in producing more kinds of flavonols, andGymnophyton appears similar toMulinum in the production of both chrysoeriol and quercetin as well as relatively few compounds. The flavonoid profile ofAsteriscium glaucum is reported as well. In general, a more homogeneous flavonoid compound composition for the Apiaceae is suggested.  相似文献   

11.
InMicrocarpaea muscosa gametogenesis, embryo sac development (Polygonum type), endosperm development (cellular), embryogeny (Onagrad type), and seed structure are described. The different modes of endosperm development withinGratioleae are compared.  相似文献   

12.
Studies on chromosome numbers and karyotypes in Orchid taxa from Apulia (Italy) revealed triploid complements inOphrys tenthredinifera andOrchis italica. InO. tenthredinifera there is no significant difference between the diploid and the triploid karyotypes. The tetraploid cytotype ofAnacamptis pyramidalis forms 36 bivalents during metaphase I in embryo sac mother cells. Aneuploidy was noticed inOphrys bertolonii ×O. tarentina with chromosome numbers n = 19 and 2n = 38. There were diploid (2n = 2x = 36), tetraploid (2n = 4x = 72), hexaploid (2n = 6x = 108) and octoploid (2n = 8x = 144) cells in the ovary wall of the diploid hybridOphrys apulica ×O. bombyliflora. Evolutionary trends inOphrys andOrchis chromosomes are discussed.  相似文献   

13.
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15.
Kengyilia laxiflora (2n = 42) was cytogenetically studied with testersK. hirsuta (2n = 42, PPStStYY) andRoegneria kamoji (2n = 42, HHStStYY). Our data suggested thatK. laxiflora may possess a modified P genome, the P1. Its St and Y genomes may also contain some structural changes and are more closely related to the St and Y genomes ofK. hirsuta than to those ofR. kamoji. Kengyilia laxiflora is reproductively separated from bothK. hirsuta andR. kamoji. These results indicated thatK. laxiflora is a good species in the genusKengyilia.  相似文献   

16.
Eight species in Pleomassariaceae are described and illustrated. They are Pleomassaria maxima, Pl. swidae, Pl. siparia “type A,” Prosthemium canba, Asteromassaria macroconidica, A. pulchra, Splanchnonema mori, and S. argus. Of these, Pl. swidae on twigs of Swida controversa, Pr. canba on Betula ermanii, and A. macroconidica on twigs of Prunus ×yedoensis and an unknown woody plant are new. Three species, Pl. siparia “type A,” A. pulchra, and S. argus, are reported from Japan for the first time. A new combination, S. mori (≡ Massaria mori), is proposed.  相似文献   

17.
Ribosomal DNA sequences were employed to infer relationships among EuropeanPottiaceae. Intragenic spacer I was sequenced for sixTrichostomoideae (Eucladium verticillatum, Pleurochaete squarrosa, Tortella flavovirens, T. nitida, T. tortuosa, Trichostomum brachydontium) and seven taxa from the other European subfamilies included inPottiaceae (Bryoerythrophyllum recurvirostrum, Didymodon vinealis, Microbryum starkeanum, Tortula muralis, Syntrichia ruralis, Weissia controversa andTimmiella cf.barbuloides). Cladistic analysis of sequence data shows close relationships betweenPleurochaete, Tortella andWeissia. Tortella appears to be paraphyletic, as it includesPleurochaete, Weissia andTrichostomum. Weissia, therefore, seems to be better placed inTrichostomoideae than, as traditionally done, inPottioideae. NeitherMerceyoideae norPottioideae appear to be monophyletic sensu stricto, at least within the limits of the taxa in analysis. Within the latter subfamily,Syntrichia is clearly separated fromTortula. These results would suggest that taxonomy inPottiaceae does not depict the pattern of descent, and therefore is in need of revision.  相似文献   

18.
This study examined the effects of the native cactus moth borer, Melitara prodenialis, and the invasive cactus moth borer, Cactoblastis cactorum, on two common cactus species, Opuntia stricta and O. humifusa at coastal and inland locations in central Florida. Opuntia stricta were present only at coastal sites and O. humifusa were present at coastal and inland sites. Throughout the duration of the study, coastal plants were subject to damage solely by C. cactorum and inland plants solely by M. prodenialis. Results showed marginally significantly higher numbers of eggsticks on O. stricta than O. humifusa and significantly higher numbers at coastal sites than at inland sites. There was also significantly higher moth damage on O. stricta than O. humifusa and at coastal sites than inland sites, but not significantly so. However, there was a higher level of plant mortality for O. humifusa than for O. stricta and a significantly higher level of cactus mortality at inland sites when compared to coastal sites. This increased mortality may be due to increased attack by true bugs, Chelinidea vittiger, and by Dactylopius sp., combined with attack by M. prodenialis. Inland plants also tended to be smaller than coastal plants and could be more susceptible to the combined effects of all insects. Further long-term research on coastal cactus survival when attacked and unattacked by Cactoblastis is necessary to fully determine the effects of this moth on Opuntia survival.  相似文献   

19.
A new species of the genusLaboulbenia, L. diplocheilae, has been established for specimens on the host genusDiplocheila (Coleoptera, Carabidae, Licinini).Laboulbenia diplocheilae is easily distinguished fromL. proliferans var.divaricata onChlaenius by the absence of a black constriction on the outermost branch of the outer appendage and by the simple stalks subtending grouped antheridia borne on appendage branches in the middle of the appendage system.  相似文献   

20.
The occurrence of eight biflavones belonging to the biluteolin series, the apigenin-luteolin series and the 2,3-dihydro-biluteolin series, and one monomeric flavone with an acid group, was investigated in six taxa ofBartramia with emphasis on sect.Ithyphyllae. The variation of biflavone profiles contributes to the characterization of theBartramia species studied; substitution patterns signalize relevance also on the sectional level. Based upon the flavonoid composition,Bartramia afro-ithyphylla is suggested to be transferred from sect.Ithyphyllae to sect.Bartramia of the genusBartramia.  相似文献   

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