摘要:

Karyotypes of three eastern North American taxa ofActaeawere investigated. Their karyotypes are as follows:Actaea rubraand its albino f.neglectahave identical karyotypes. The karyotypes ofA. rubraf.rubraandA. pachypoda, two very distinct species, though similar, are clearly differentiated by the presence of a secondary constriction at the distal end of the long arm in the shorter of the two pairs of J-shaped chromosomes ofA. pachypoda. The karyology of the three North American taxa is somewhat different from that reported by Kurita forA. asiatica.

ISSN:0008-4026    

DOI:10.1139/b66-137

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

A new species of the Nidulariaceae or bird's nest fungi is described from the Canadian Rockies, namedCyathus helenae, and illustrated. The fungus appears to be unique in growing upon alpine scree at an altitude of 7000 ft. This very small plant differs from other known small species in the faint plication of the inner surface of the peridium, in the distinctly nodular tomentum, and in spore size.

ISSN:0008-4026    

DOI:10.1139/b66-138

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Xanthomonas phaseolivar.fuscans(Burkh.) Starr & Burkh. in naturally infected bean seeds stored at −20 to 35 °C retained its viability, virulence, and physiological properties for 3 years. Agar cultures of the pathogen maintained at −20 to 20 °C also retained their pathogenicity and physiological characters throughout the test period but showed less virulence than the seed-borne isolates by the end of 33 months. The viability of agar cultures held at 25, 30, and 35 °C was lost after 24, 18, and 9 months of storage, respectively.The effects of 24 carbon sources on the growth of the pathogen have been determined. The production of a brown diffusible pigment by the organism was influenced by temperature, aeration, and the carbon source. Sugar alcohols did not support good growth or inhibit pigment formation. Most carbohydrates, which supported good or fair growth of the organism, seemed to inhibit pigment production or its expression.

ISSN:0008-4026    

DOI:10.1139/b66-139

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The photosynthetic fixation of14CO2was studied in 10 species of chlorophycean algae and in 9 isolates of prasinophycean algae of the genusTetraselmis.Green seaweeds had photosynthetic rates of 2.2 to 4.4 mg CO2 × h−1 × g−1, accumulated starch, glucose, fructose, and sucrose, and excreted very little recent photosynthate.Dunaliellaspp. were distinguished by a high level of organic excretion (to 29.2% of the14C fixed in 2 hours), the production of glycerol and hydrogen sulfide, and the absence of dimethyl-β-propiothetin.Tetraselmisspp. excreted relatively small amounts of photosynthate in 2 hours, and produced mannitol and dimethyl-β-propiothetin but not hydrogen sulfide.

ISSN:0008-4026    

DOI:10.1139/b66-140

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

In selfing studies with four cultures of race 11 and one of race 10 of wheat stem rust (Puccinia graminisPers. f. sp.triticiErikss. and Henn.) segregation ratios indicated that a single dominant gene governs virulence on the varieties Arnautka and Mindum and single recessive genes govern virulence on the varieties Marquis-Sr8, Marquis-Sr9a, and Marquis-Sr11. Virulence on Marquis-Sr9bappeared to be recessive but the observed ratio was a poor fit to a single factor ratio.

ISSN:0008-4026    

DOI:10.1139/b66-141

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Antigenic differences between isolates of carnation mottle virus were detected by immunodiffusion in agar plates. A specific precipitation pattern characterized by partial intersection of the precipitate lines of certain isolates and a reference virus antigen suggested that these antigens were similar to but not identical with each other. The "spur" pattern between these cross-reacting isolates was shown not to be the result of a reaction with healthy host components or unrelated virus contaminants. These results were substantiated by cross-absorption tests.

ISSN:0008-4026    

DOI:10.1139/b66-142

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The spectral composition of near ultraviolet and visible radiation in the open and in pure stands ofPinus resinosaAit. andAcer saccharumMarsh was determined for cloudless, hazy, and overcast conditions. In the open, the spectral composition of light on clear and overcast days differed significantly only in quantity. Beneath the forest canopy the quality of light was changed greatly with respect to the open when the incoming radiation was direct sunlight. The selectivity of absorption and reflection in the visible spectrum by the deciduous canopy was shown quite conclusively while the conifer canopy appeared to be fairly neutral. On overcast days and during the leafless period of the deciduous canopy, transmission of the incident radiation was very high while the change in light quality appeared to be slight. The results are discussed in relation to the light-intercepting capacities of the leaves of the different species, the light climate in the forest, and silvicultural management.

ISSN:0008-4026    

DOI:10.1139/b66-143

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The temperatures of 18 fires in an open jack pine barren near Timmins, Ontario, have been recorded. The maximum temperature recorded was 545 °C, although in other determinations fire temperatures in excess of 1000 °C were reached. The mean temperature of all fires was 340.6 ± 133.2 °C. Three fires at 230, 345, and 545 °C were considered in detail.The maximum temperature of a fire was normally recorded at heights of 5 cm or 10 cm above the surface. Maximum temperatures of hotter fires usually occurred at greater heights than cooler ones. Duration and the temperature ("intensity") of the fire are important aspects of fire studies.

ISSN:0008-4026    

DOI:10.1139/b66-144

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The maximum temperature attained during surface fires in a jack pine barren, near Timmins, Ontario, was found to vary from 120° to 545 °C. The temperature of the fire is dependent upon a number of variables, of which vegetation biomass and height, wind speed, the speed of the fire front, and moisture content of litter and vegetation, are most important.Temperatures of fires studied depended mainly on the height and amount of burning vegetation. All fires with temperatures greater than 350 °C occurred in dense vegetation with more than 235 g/m2. The effects of wind velocity were less obvious; however, high wind speed appeared to have a cooling effect on the fire temperature.There was no evidence of any significant effect of atmospheric humidity on fire temperature.

ISSN:0008-4026    

DOI:10.1139/b66-145

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Electron microscopy showed that the haustoria ofErysiphe cichoracearumwhich were randomly scattered in the epidermal cells of sunflower bathed in a cavity which was surrounded by the plasma membrane of the host. After infection of the sunflower cells, an increase in concentration of the host cytoplasm was noted. The haustorium was an elongated ellipsoidal body with tortuose branches which emerged from each end and wove back over the body. The branches seldom came into contact with each other or the body of the haustorium or the surrounding membrane. The possibility of the branches being vestigial or functional is discussed. The haustorial body and branches contained numerous chondriosomes, vesicles, and large electron-dense bodies. These bodies formed in vesicles by coalescence of smaller dense bodies. The chondriosomes were mainly the chondriocont type. In the body of the haustorium a nucleus and an opaque nucleolus with two electron-transparent areas were observed. Encapsulation material was scattered irregularly along the host membrane and was structureless, which suggests that it was waste material. The rest of the cavity was filled with a solution through which interchange between the host and fungus occurred. Active transport from the host protoplasm to the fungus was suggested. No evidence was obtained for cytoplasmic connections between the parasite and the host.

ISSN:0008-4026    

DOI:10.1139/b66-146

出版商:NRC Research Press    

年代:1966

数据来源: NRC