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1.
The paper deals with some of the contributions made from India by various research workers towards our knowledge of the fungus genusPhytophthora de Bary, in the fields of morphology, disease production, occurrence and distribution of species, host range, physiology, taxonomy and control measures. Out of the total of fifteen species and five varieties ofPhytophthora reported from India, five species (viz.,P. arecae, P. palmivora, P. colocasiae, P. parasitica andP. infestans, and four varieties ofP. parasitica, viz.,P. parasitica var.macrospora, var.sesami, var.piperina and var.nicotianae) assume considerable parasitic roles inciting serious diseases like seedling-blights, wilts, cottoney-leaks, foot-rots, blights, budrot and rots of fruits, nuts, tubers and corms etc. They are widely distributed in various parts of this country, and are mostly prevalent in rainy seasons.Phytophthora palmivora, andP. parasitica were found to have a wide host range.  相似文献   

2.
William R. Buck 《Brittonia》1983,35(3):248-254
The genusFabronia in South America is found to represent five taxa:F. ciliaris var.ciliaris, F. ciliaris var.wrightii,F. ciliaris var.polycarpa,F. macroblepharis andF. jamesonii. Synonymy, brief discussion, illustrations and a key are provided.Fabronia enervis Herz., hom. illeg., is the basis for the new genusMahua.  相似文献   

3.
Two desert shrubs belonging toEriogonum subgen.Eucycla sect.Corymbosa are described from southern Utah and northern Arizona.Eriogonum mortonianum, endemic to red clay hills southwest of Fredonia, in extreme northeastern Mohave County, Arizona, is most closely related toE. smithii, a species endemic to the San Rafael Desert of Emery County, Utah, but differs in having wider leaves, a much more branched inflorescence, and smaller, pale-yellow or white flowers.Eriogonum leptocladon var.papiliunculi, found in central Garfield and eastern Kane counties, Utah, southward into northern Coconino and Navajo counties, Arizona, is distinguished from var.leptocladon by its white flowers and from var.ramosissimum by its glabrous stems.  相似文献   

4.
Edwin B. Smith 《Brittonia》1983,35(2):164-169
Coreopsis californica var. newberryi, a new variety, differing from typical material ofC. californica in achene morphology, is proposed. Achene spotting in the two varieties exhibits maternal inheritance.  相似文献   

5.
Acacia guilandinae DC. is recognized asMimosa guilandinae (DC.) Barneby, endemic to French Guiana and adjoining Amapá, Brazil;M. pseudo-obovata is subordinated as a Brazilian var.pseudo-obovata (Taub.) Barneby to CaribbeanM. ceratonia L.; andM. laticifera is found synonymous withM. obovata Benth. Diagnostic morphological characters of each taxon are presented in key form.  相似文献   

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7.
Aboriginal cultivators selected a phylogenetically novel fruit shape during the domestication ofProboscidea parviflora ssp.parviflora var.Hohokamiana. The extremely long rostrum of the domesticated var.Hohokamiana is unique for the Martyniaceae. Rostrum length and width are significantly correlated in the wild var.parviflora, but in var.Hohokamiana aboriginal cultivators apparently selected for a weaker correlation between these variables. In both varieties there is an allometric relationship between rostrum and “capsule” lengths, with the former increasing proportionately faster than the latter. The above allometric relationship and the decrease in correlation between rostrum length and width are advantageous to aboriginal cultivators because the proportionately longer and thinner rostra are better for basketmaking. Comparisons of the data presented herein with data from other plants suggest that similar growth factors have been responsible for changes in fruit shape resulting from domestication.  相似文献   

8.
Four new species and one new variety of Rubiaceae from French Guiana are described:Psychotria alloantha, P. cypellantha, P. squamelligera, P. viridibractea, andSipanea ovalifolia var.villosissima.  相似文献   

9.
Somatic chromosomes ofPinus nigra var.maritima (2n=24) were sequentially stained with DNA binding base-specific fluorochromes, chromomycin A3 (CMA) and DAPI. Many CMA- and DAPI-bands appeared at intercalary and/or proximal regions of most chromosomes. These banding patterns reversely related. Individual chromosomes were easily identified using these fluorescent banding patterns.  相似文献   

10.
Arnold Tiehm 《Brittonia》1989,41(2):152-155
Types are indicated for 28 new names inadvertently published in Rydberg’sFlora of Colorado. Included are a discussion as to the validity of these new names and an explanation of the causes of this oversight. A lectotype ofLupinus decumbens var.argentatus is herein designated by Rupert C. Barneby.  相似文献   

11.
12.
Chromosome numbers of 46 samples referable to the speciesJasione montana L. were examined. The material originated from different localities in Portugal, France, the Netherlands, Germany, Switzerland, Austria, Czechoslovakia, Poland, and the Soviet Union. All the samples were found to be diploid, having 2n=12 chromosomes. The aneuploid number, 2n=14, is shown to be limited to the var.litoralis Fries. Polyploidy has not been observed.  相似文献   

13.
14.
InCallithrix, Saguinus, Aotus, andCallicebus other group members than the mother participate in infant care. Differences among these species are obvious in respect to the time of being off any caregiver, and in respect to the carrying position (Aotus andCallicebus). Alloparental care, a basic behaviour pattern in these species, has evolved from the parking behaviour of the prosimians. The infants are «parked» at other group members.  相似文献   

15.
A total of 22 strains of known species of the genusSchizosaccharomyces Lindner were evaluated by numerical taxonomy based on conventional identification tests. The results of numerical taxonomy were supplemented by a determination of activity of extracellular hydrolytic enzymes, especially 1,3-β-D-glucanase, RNAase and DNAase. All the strains tested were capable of utilizing the 1,4-capable of utilizing the 1,4-α-D-glucan tamarind. Study of life cycles of these organisms showed that extracellular hydrolytic enzymes were present mainly at the time of maturation of asci and release of their walls. Strains forming four-spore asci could be comprised in the single speciesSchizosaccharomyces pombe Lindner as two varieties:S. pombe var.pombe andS. pombe var.malidevorans. The two varieties differ in maltose fermentation. Urease is produced by all strains irrespective of the life cycle phase. A number of hydrolytic enzymes are not produced by the genusSchizosaccharomyces (e.g. amylolytic enzymes) despite the fact that oligomers of the maltose type are utilized. Species of the genusSchizosaccharomyces lack also xylanase, cellulases, mannase, and are incapable of degrading carrageenan and acid polysaccharides.  相似文献   

16.
Stanley L. Welsh 《Brittonia》1981,33(3):294-303
This paper is presented in tribute to Rupert C. Barneby on the occasion of his seventieth year. Described as new areArtemisia norvegica var.picetorum Welsh & Goodrich,Astragalus lentiginosus var.higginsii Welsh & Thorne,Cirsium barnebyi Welsh & Neese,Cymopterus beckii Welsh & Goodrich,Machaeranthera kingii var.barnebyana Welsh & Goodrich,Thelypodiopsis barnebyi Welsh & Atwood,Xanthocephalum petradoria Welsh & Goodrich, andXylorhiza cronquistii Welsh & Atwood.  相似文献   

17.
18.
Soils high in magnesium derived from ultramafic rocks (serpentine, peridotite, and dunite) in northwestern United States support endemic as well as wide-ranging but edaphically indifferent(bodenvag) species. The latter occur widely on diverse rock formations of the region. Severalbodenvag species are shown to respond ecotypically to ultramafic soils. Of 18 species tested, all but three are differentiated into strains either tolerant or intolerant of ultramafic soils. Tests for edaphic preferences were conducted with seedlings and mature transplants on ultramafic soils. Growth performances were determined in greenhouse pot tests, outdoor soil bins, and by transplants in the wild. Herbaceous perennials (e.g.,Achillea millefolium, Fragaria virginiana, Prunella vulgaris, Rumex acetosella) gave the clearest ecotypic differences. Woody species either showed only slight ecotypic response(Spiraea douglasii var.menziesii andGaultheria shallon) or delayed the expression of their genotypic adaptability(Pinus contorta). Where ultramafic abut non-ultramafic soils, those populations ofbodenvag species that grow in non-ultramafic habitats can have a significant proportion of individuals tolerant to ferromagnesian soils (e.g.,Achillea millefolium). This suggests gene flow between populations of contrasting edaphic sites and possibly preadaptedness for the ultramafic habitat. Strains of two introduced weeds(Prunella vulgaris andRumex acetosella) have become ecotypically tolerant to ultramafic soils, probably within the last 75 years.  相似文献   

19.
The N 1-methyladenosine residue at position 58 of tRNA is found in the three domains of life, and contributes to the stability of the three-dimensional L-shaped tRNA structure. In thermophilic bacteria, this modification is important for thermal adaptation, and is catalyzed by the tRNA m1A58 methyltransferase TrmI, using S-adenosyl-l-methionine (AdoMet) as the methyl donor. We present the 2.2 Å crystal structure of TrmI from the extremely thermophilic bacterium Aquifex aeolicus, in complex with AdoMet. There are four molecules per asymmetric unit, and they form a tetramer. Based on a comparison of the AdoMet binding mode of A. aeolicus TrmI to those of the Thermus thermophilus and Pyrococcus abyssi TrmIs, we discuss their similarities and differences. Although the binding modes to the N6 amino group of the adenine moiety of AdoMet are similar, using the side chains of acidic residues as well as hydrogen bonds, the positions of the amino acid residues involved in binding are diverse among the TrmIs from A. aeolicus, T. thermophilus, and P. abyssi.  相似文献   

20.
Grains ofTriticum monococcum L. var.sofianum Körn. were treated with 0·1mm, 0·2mm and 0·3mm solutions of N-nitroso-N-methylurea (MNH), with 0·03m solution of buthylmethane sulphonate (BMS) and with X-rays in doses of 5 000r and 10 000r. The germination and development of individual colors of chlorophyl mutants were observed by the system developed byLamprecht (1960). All the mutants induced were classified according to their color changes into three main categories-homogenous unicolor, homogenous multicolor and heterogenous multicolor. In the last type the colors of individual leaves of the same plant varied. Anthocyanin mutations “albina” and “albino-transvirgata” sometimes coincided with the chlorophyll mutations. Some chlorophyll mutations showing complicated groups of colors appeared which were beyond the scale of classification by ordinary systems. The largest proportion in the spectrum of chlorophyll mutations, induced by MNH and X-rays was occupied by mutations of thealbina type. The broadest mutation spectrum in our experiments was induced by the application of 0·3mm MNH. The doses of X-rays used induced relatively higher numbers ofalbina-type chlorophyll mutations than MNH and BMS. In our experiments we succeeded in inducing on medium size samples ofTriticum monococcum L. var.sofianum Körn not only almost all types of chlorophyll mutations, induced byFujii (1960, 1962) andMatsumura (1960), but in addition also a great number of other even more complicated chlorophyll mutations, which have never been previously described inTriticum monococcum. L.  相似文献   

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