摘要:

Comparisons were made of growth inhibition of two saprophytic (Trichoderma viride, Trichocladium asperum) and two plant parasitic soil fungi (Ophiobolus graminis, Fomes annosus) by antibiotics. The fungi were grown on an agar medium containing various concentrations of one of the antibiotics: acti-dione, gliotoxin, griseofulvin, patulin, or trichothecin. In general the two parasites tended to be more sensitive than the saprophytes, but there were several individual exceptions. Moreover, the comparative responses of the fungi at different antibiotic concentrations were frequently not proportionately related. The results are discussed in relation to the possible effects of antibiotics on fungi in natural soil.

ISSN:0008-4026    

DOI:10.1139/b61-037

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

A collection ofAnemone drummondiiS. Wats. from Jasper National Park, Alberta, has been found to be hexaploid, 2n = 48. Chromosome pairs belonging to each of the groups, I–VIII, can be identified with few exceptions, on the basis of relative length and centromere position. Since several well-characterized pairs are represented only once, the allopolyploid nature of this species is evident. Metaphase plates from hybrids withA. multifidaPoir. var.hudsonianaDC. allow a direct comparison between the parental karyotypes. Similarity of one chromosome set from each parent suggests that these sets were contributed by the same or by closely related ancestral species.

ISSN:0008-4026    

DOI:10.1139/b61-038

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The ascorbic acid content of winter wheat varieties, germinated in the dark at various temperatures on the surface of moist vermiculite, was much higher at a hardening temperature of 1.5 °C than at higher temperatures of 5°, 10°, or 20 °C. There were no differences between the ascorbic acid contents of wheat grown at the three higher temperatures. Ascorbic acid content was dependent on the stage of development at all temperatures. At 1.5 °C, the ascorbic acid content increased during the first 6 weeks of growth (shoots about 15 mm) and then decreased rapidly. This variation in ascorbic acid content was closely associated with the increase and decrease in cold hardiness of wheat grown under similar conditions.Ascorbic acid content was highest in shoots, intermediate in roots, and lowest in the endosperm of wheat grown for 6 weeks at 1.5 °C.At hardening temperatures (1.5° and 3 °C) the more cold hardy winter wheat varieties had higher contents of ascorbic acid. At higher temperatures the differences between varieties were small. The ranking of varieties by ascorbic acid content could be influenced by relative stages of growth.Artificial cold hardiness was imparted to winter wheat seedlings by feeding them aqueous ascorbic acid solutions of adequate concentration. The ascorbic acid content of leaves required for artificial hardening appeared to be similar to that accumulated in sprouts hardened fully by growth at low temperature.

ISSN:0008-4026    

DOI:10.1139/b61-039

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The inheritance in oats of reaction to some new races and to some well-known races of oat stem rust,Puccinia graminisPers. f. sp.avenaeErikss. and Henn., was investigated in the crosses Jostrain × Eagle, Canuck × Cherokee, and R.L. 524.1 (Hajira × Banner) × Eagle. The resistance of the variety Jostrain to races 1, 3, 4, 13, and 13A was conferred by a single gene, here designated as theEgene in accordance with the practice of designating genes for stem rust resistance by capital letters. Canuck, a derivative of Jostrain, carries the newEgene and the previously identifiedBgene. The resistance of R.L. 524.1 to all races is conferred by two major genes and a modifying gene. One of the major genes acts like the well-knownBgene which confers resistance to all races except 6A, 7A, 8A, and 13A. The other major gene apparently is a new gene in oats for resistance to stem rust and is here designated theFgene. TheFgene confers resistance to all races but a modifying gene is required along with it for resistance to race 7.

ISSN:0008-4026    

DOI:10.1139/b61-040

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

Protectant fungicidal action of mixtures of nabam, zineb, nickel chloride, and zinc sulphate was evaluated by means of a "microbeaker method" and the slide germination method, using as test organisms the fungi causing leaf rust of wheat, crown rust of oats, early blight of tomatoes, and brown rot of peaches. All of the fungicides tested were more effective against the two rusts than against the organisms causing early blight and brown rot. The relatively insoluble nickel ethylenebisdithiocarbamate was much less effective than the other chemicals tested. Ratios (w/w) of nickel chloride hexahydrate to zineb around unity and to nabam plus zinc sulphate from 2–10 to 1 showed an unfavorable effect on fungitoxic activity against urediospores ofP. recondita. The ratio showing greatest antagonism varied, depending on the test organism used and whether or not tankmix or wettable powder zineb was used. The formation of nickel ethylenebisdithiocarbamate in the aqueous solution and its low fungicidal activity adequately explain the results obtained.

ISSN:0008-4026    

DOI:10.1139/b61-041

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The reduction of thiram by microorganisms, observed qualitatively by previous workers, is shown to occur in the external solution with spores ofGlomerella cingulata. Quantitative examination of the process indicates that in the absence of copper ions there is no measurable uptake of either thiram or its reduced form, dimethyldithiocarbamic acid, by the spores. In the presence of copper ions, dimethyldithiocarbamate is lost from solution and fungitoxicity is increased. Evidence of uptake of copper dimethyldithiocarbamate by the spores is not conclusive, however, due to the formation of a precipitate. The exudate from the spores in time solubilizes this precipitate with a concomitant reversal of fungitoxicity. A new technique, wherein a paper strip treated with a metal salt is laid at right angles to one treated with thiram or a dithiocarbamate on an agar sheet seeded withG. cingulataspores, has supplied corroboration of the hypothesis involving the two copper dimethyldithiocarbamate complexes in the bimodal dosage response of microorganisms to dithiocarbamate toxicants.

ISSN:0008-4026    

DOI:10.1139/b61-042

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The occurrence of tetrasporangia and carposporophytes on the same thallus is reported inEuthora cristata(L. ex Turn.) J. Ag. collected in the Maritime Provinces, the first report of such a phenomenon in this genus.

ISSN:0008-4026    

DOI:10.1139/b61-043

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

The validity of many of the strains ofFusarium oxysporumf.cubensewhich have been reported rests primarily upon the cultural criteria used in their differentiation. An examination of certain of these cultural features, such as the presence or absence of odor, pigmentation, 'interaction', and colony morphology did not permit conclusive identification of strains. 'Finger printing' by means of chromatographic assay of exogenous amino acids, measurements of growth, and the production of fusaric acid by single-spore cultures of strains of the banana-wilt fungus confirmed initial observations that so-called clones, cultivars, varieties, and groups overlapped and were inseparable.Methods for the isolation of single microconidia from the lumen of individual host cells, a microculture technique which employed 0.5 ml of liquid medium, and the determination of 27 ninhydrin-reactive substances in culture filtrate are described.

ISSN:0008-4026    

DOI:10.1139/b61-044

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

A virus disease occurring in the Lloyd George variety of red raspberry (Rubus idaeusL.) in British Columbia has been identified as raspberry vein chlorosis, a disease previously reported from Scotland. The virus was transmitted to the Lloyd George and Washington varieties of red raspberry, loganberry (R. loganobaccusBailey), and the Alpine strawberry (Fragaria vescaL.) by the aphidAphis idaeiV.d.G. In each of these hosts, the characteristic symptom was a net-like chlorosis of the tissue bordering the smaller veins of the leaf. The large raspberry aphid,Amphorophora rubi(Kalt.), was not a vector. Experiments usingA. idaeishowed that most individuals require more than 1 day on the virus source to become viruliferous. The length of time that aphids remained viruliferous depended upon the conditions of the test; viruliferous aphids feeding upon healthy raspberry plants lost the ability to transmit the virus within a day, while those feeding upon strawberry, or held in a Petri dish without food, retained the virus longer than 1 day.

ISSN:0008-4026    

DOI:10.1139/b61-045

出版商:NRC Research Press    

年代:1961

数据来源: NRC

摘要:

A cytogenetic study of the genusSaxifragain the Pacific Northwest has been initiated as a contribution toward a better understanding of relationships within the genus. The present paper reports work done on nine species or groups of morphologically similar species and varieties (each group termed a "plexus") which have so far been studied. The nine species or groups of species areS. tolmiei, S. bronchialis, S. integrifolia, S. ferruginea, theS. montanensisplexus, theS. occidentalisplexus,S. odontoloma, S. lyalliiandS. mertensiana. Meiosis in pollen mother cells of one species was found to be generally regular, pollen fertility high. In every other species or plexus a variable and sometimes very high degree of meiotic irregularity was present. Pollen fertility was often much reduced. The cause of meiotic disturbances has not yet been discovered. Consideration is given to the ways in which the species may succeed in spite of reduced pollen fertility. Such irregular meiotic divisions would be difficult to use in cytogenetic studies as a standard for comparison with meiosis in artificial hybrids.

ISSN:0008-4026    

DOI:10.1139/b61-046

出版商:NRC Research Press    

年代:1961

数据来源: NRC