摘要:

Studies have been made on the effect of benzimidazole and nickel on the chlorophyll metabolism of detached etiolated and green leaves of Khapli wheat. It was found that benzimidazole stimulated the formation of chlorophyll and protects the latter from rapid destruction. The protective effect was most prominent in treated leaves in the dark. The effect of nickel ion differs from benzimidazole only in respect to its inhibition of chlorophyll formation. Evidence obtained indicates that the destruction of chlorophyll in light and in dark are probably two independent processes.

ISSN:0008-4026    

DOI:10.1139/b59-059

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Aqueous extracts from 30 species of red algae were treated with κ-carrageenase, a specific hydrolase for κ-carrageenin. The total reducing power of the hydrolyzate indicated that the algae could be divided into three groups on the basis of the content of κ-carrageenin. Group 1 includedGigartina acicularis, G. radula, G. pistillata, G. christata, and Iridaeasp. with a low value. Group 2 includedChondrus crispus, G. stellata, G. stiriata, Rhodoglossum affine, Furcellaria fastigiata, andEndocladia muricata, all with values comparable with that inC. crispus. Group 3 includedHypnea musciformisand aYatabellasp. with a value greater than that forC. crispus. The occurrence of agarose and of κ-carrageenin in the Rhodophyceae is discussed as a factor in their taxonomy.

ISSN:0008-4026    

DOI:10.1139/b59-060

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Sunflower seed harvested from diseased plants in aVerticilliumnursery in Manitoba, surface-sterilized and plated on potato sucrose agar, gave rise to colonies ofVerticillium albo-atrumReinke and Berth. Microsclerotia of the organism were confined to the hull and testa of the infested seeds. The fungus was not found in any portion of the seed inside the testa. Approximately 50 per cent of the infested seeds germinated on the agar plates; the rest apparently were dead. Symptoms typical ofVerticilliuminfection developed in sunflower plants in a plot on clean soil sown with seed harvested from diseased plants in aVerticilliumnursery. No diseased plants were found in adjacent plots sown with seed from healthy plants.Failure to isolate the pathogen from seed taken from typically diseased plants in a farm field near theVerticilliumnursery may signify that seed infestation occurs only under favorable circumstances. The factors predisposing to such infestation are not yet known. Lack of consistency in isolation of the pathogen from seed taken from diseased plants from various sources parallels the contradictory results obtained by workers studying seed dissemination ofV. albo-atrumin other crops.

ISSN:0008-4026    

DOI:10.1139/b59-061

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Among the many fungi collected in northern Canada by government biological survey parties are agarics belonging to the Tricholomataceae. Over 100 collections were examined in this study. Twelve genera and 33 species are represented. The records of these species in northern Canada are of value in determining the limits of distribution.Myxomphaliais raised to generic rank. The following new combinations are proposed:Clitocybe luteovitellina, C. posti, C. septentrionlis, C. umbellifera, Lepista irina, Myxomphalia maura.

ISSN:0008-4026    

DOI:10.1139/b59-062

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

A close correlation was found to exist between the development of a bark canker in nursery-grownPopulus trichocarpaTorrey and Gray, caused byFusarium lateritiumNees., and the moisture content of the living bark. When bark moisture was expressed as a percentage of the amount of water required to saturate the sample under experimental conditions, relative turgidities of 80% or more inhibited canker development which, however, occurred normally at lower percentages. Studies of the epidemiology ofFusariumcanker in the nursery afforded evidence in support of the limiting effect of bark moisture on canker development. Thus during the dormant season of 1957–58, the monthly average temperature was higher than the minimum temperature for the growth ofF. lateritiumon potato dextrose agar, and the relative turgidity did not reach the inhibiting value of 80%. Cankers continued to develop throughout this period. During the growing season while temperatures were still more favorable for fungus development, no extension of cankers occurred in the nursery trees, apparently because, during the growing period, the relative turgidity was in excess of 80%. Canker development was prevented during the winter by placing dormant cuttings in water, which likewise increased the moisture content of the bark above the 80% level.During the dormant season the bark of field-grown black cottonwoods maintained relative turgidity values of approximately 80% or higher and the disease could not be found on these trees.

ISSN:0008-4026    

DOI:10.1139/b59-063

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Wood moisture was measured in the butt of healthy and decadent yellow birch trees growing on various sites in the summers of 1950 and 1952. The moisture content decreased from almost 100% in May to about 60% in late June when the leaves were fully unfolded. Wood moisture was usually 5 to 15% higher in the butt of decadent trees than in healthy trees during the 2 years of investigations. It was higher in the trunk of trees on a dry site during a wet summer and on a wet site during a somewhat dry summer.Relative turgidity in leaves was measured in mature trees as well as in leaves of seedlings growing on soils with varied moisture contents. Relative turgidity was usually less during the day. During periods of drought it decreased even during the night. Exceptions observed may have been caused by leaf absorption of dew. In young birch seedlings relative turgidity values varied between 65 and 50% in soils ranging from 100 to 70% of field capacity. As the soil wilting point was approached, relative turgidity of leaves decreased to about 35%.

ISSN:0008-4026    

DOI:10.1139/b59-064

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

In a study of the non-sporulating hyaline saltants ofVerticillium lateritiumit was found that the incidence of saltation in subcultures increased as the parent stock cultures became more aged. The factor (factors) responsible for this resided not in the spores but in the hyphae and it (they) was (were) probably water soluble because washing in distilled water appeared to rid the inoculum of any tendency to cause saltation.Three types of concentric zonations were observed in cultures ofV. lateritium: (a) those produced by stimulation to sporulation due to the action of light of a specific intensity, period, and wave length, following a dark period in excess of a minimum of 9 hours; (b) those caused by zones of reduced sporulation occurring as a result of poor mycelial development resulting from temperature changes above or below the optimum for growth; (c) those formed in a saturated atmosphere where a physical collapse of some of the conidiophores in the center of the colony occurred due probably to excessive condensation. Variations in the humidity of the atmosphere caused neither stimulation nor inhibition to sporulation.

ISSN:0008-4026    

DOI:10.1139/b59-065

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Plant-bearing beds have been discovered by J. G. Fyles in late-glacial deposits from the Englishman River section, Vancouver Island, B.C. Radiocarbon dating indicated an age of ca. 12,000 years for these beds. Fossil cones ofPinus contoriaDougl. and leaves ofDryas drummondiiRichards, were discovered and identified. Palynological study indicates that climate at the time was colder than the present.

ISSN:0008-4026    

DOI:10.1139/b59-066

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The growth responses ofHirsutella giganteato different nitrogen sources were studied. Experiments showed that the mycelium hydrolyzate contained at least 14 of the amino acids, that the fungus was unable to utilize inorganic nitrogenous compounds, that ammonium tartrate was inferior to amino-nitrogen, and that theLorDLisomers of the different amino acids induced better growth than did theDform.The 10 most suitable nitrogen sources in order of decreasing growth were:L-glutamic acid,L-tyrosine, ammonium tartrate,DL-aspartic acid,L-proline,L-arginine,L-leucine,DL-α-alanine,DL-serine, andDL-histidine. The total yield, however, obtained in a synthetic medium with each of these substances was shown to be directly dependent upon the quantity of inoculum used. The enhanced growth resulting from the addition of increased inoculum is ascribed to accessory growth factors carried over with the mycelial fragments despite six washings in saline.The maximum growth ofH. giganteadeveloped in a dextrose–salts medium containingL-glutamic acid as a source of nitrogen, and yeast extract, inoculum filtrate, and liver fraction "L" as a source of growth factors.The lack of uniformity associated with nutritional studies conducted in chemically defined media has been briefly mentioned.

ISSN:0008-4026    

DOI:10.1139/b59-067

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The nuclei in the vegetative hyphae ofSchizophyllum communedo not divide in a manner directly comparable to ordinary mitosis. During division the tightly packed chromatinic granules become loosely arranged following which they contract into a densely stained bar. As division proceeds this bar of chromatin elongates and then constricts at its mid-region. At the end of division the extremities pull apart quickly to form the chromatin portions of the two sister nuclei. The Feulgen-negative central bodies decrease in size and at the end of division their remnants lie free in the cytoplasm. New central bodies arise in the maturing sister nuclei. Throughout division metaphase plates, spindles, or individual chromosomes were not observed in any of the stained or living preparations. A nuclear membrane has not been observed surrounding any of these nuclei.

ISSN:0008-4026    

DOI:10.1139/b59-068

出版商:NRC Research Press    

年代:1959

数据来源: NRC