摘要:

The distribution and general ecology of 249 macrolichen taxa is described for 230 000 km2of coniferous forest, open fens, and alpine terrain along the Mackenzie River in the District of Mackenzie, Northwest Territories, and the Peel River, a major tributary which rises in the Yukon Territory. Permafrost plays a major role in determining the plant communities that are present. Fire and man-made disturbances initiate succession. There are 45 new reports for the District of Mackenzie and 30 for the Yukon. Of the taxa, 86% are found in Europe, Asia, and North America, 9% are known from Asia and North America, whereas only 4% are restricted to North America.Pilophorus robustusis new to Canada. High mountains in the western part of the area, generally nonglaciated during the Wisconsinian, support a flora that contains many Arctic and Arctic–Alpine taxa. Amphi-Beringian species occur primarily in the north.

ISSN:0008-4026    

DOI:10.1139/b80-227

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Ultrathin sections of leaves from American elms (Ulmus americanaL.), sycamores (Platanusspp.), and two red oak species (Quercusspp.) that exhibited leaf scorch were examined by transmission electron microscopy. Rod-shaped, ripple-walled bacteria resembling the Pierce's disease organism were found consistently in tracheary elements of the primary and secondary veins of diseased plants. Smaller, ripple-walled, densely stained, irregular-shaped bodies (SDB) were found also in a matrix that lined the inner walls or filled the lumina of the tracheary elements. In leaf scorch affected American elms the bacteria were 0.3–0.4 μrn × 0.9–2.4 μm, with rounded ends. Fimbriae-like structures radiated from a few organisms. Bacteria were frequently embedded in a matrix. Pit cavities and the ends of tracheary elements were often filled with the bacteria–matrix complex. Rod-shaped bacteria were not as numerous in the diseased sycamore and oak as in diseased elm; however, SDB's were more numerous. Bacteria in sycamore (1.0–1.8 μm) and oak (1.0–2.0 μm) were slightly shorter than those in elm, many had numerous fimbriae-like hairs, and some were tapered at one end. Indirect fluorescent antibody staining showed a serological relationship between bacteria extracted from elm and oak and the Pierce's disease bacterium.

ISSN:0008-4026    

DOI:10.1139/b80-228

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Mating-type interactions between monokaryons (secondary sporidia and mycelia] ofTilletia carieswere studied. Preconjugation pegs were produced by sporidia after displacement of stimulating (opposite mating type) cells and the pegs continued to elongate. Sporidia of opposite mating types conjugated when subjected to a treatment that would disrupt fimbrial connections. Multiple hyphal tips were produced by differentiating sporidia separated from monokaryons of opposite mating type. The response was sex specific. In some instances the factors causing these responses were apparently retained in the agar substrate.

ISSN:0008-4026    

DOI:10.1139/b80-229

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The female reproductive structure ofMyrica pensylvanicacomprises a gynoecium and four second-order inflorescence bracts. The gynoecium terminates the second-order inflorescence axis. The receptacle, comprising second- and third-order inflorescence axis tissue, forms most of the gynoecial wall and gives rise to the wax-secreting papillae. Papillae, which are vascularized, are not initiated in the same manner as trichomes. An hypothesis is formulated whereby papillae may be homologized to inflorescence bracts.

ISSN:0008-4026    

DOI:10.1139/b80-230

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Eleutheris guaduaeViegas is reassessed and redisposed in a new anamorph genusEllulaasE. guaduae(Viegas) Nag Raj comb.nov.

ISSN:0008-4026    

DOI:10.1139/b80-231

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Twenty species of thermophilous fungi were identified from sugarcane bagasse at Batala in Northern India. Seven fungal species are reported from bagasse for the first time andAspergillus caespitosnsis a new record for India.Aspergillus fumigatuswas the most common fungus followed byMncor pusillus. The temperature responses of the fungi revealed 5 microthermophiles, 11 thermotolerant, and 4 true thermophiles. Three species of thermophilous fungi are reported in addition to those already recorded in the literature.

ISSN:0008-4026    

DOI:10.1139/b80-232

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Vaccinium uliginosumL. (bog blueberry), its mineral soil substrate, and the till on which the soil is developed were sampled at a site of uranium–copper–lead mineralization in the tundra of the central District of Keewatin. Levels of Cu and U in till result from dispersal of minerals glacially eroded from a metal-rich bedrock source. The pattern strongly expressed for Cu and U up to 1500 m from the source is not readily detectable for Pb.Concentrations of ashedVaccinium uliginosumgrowing on till ranged from 0.4 to 980 ppm U, 4.5 to 3973 ppm Cu, and 0.1 to 3964 ppm Pb, values greater than previously recorded for the species. The concentrations of U and Cu were significantly correlated to metal levels in till withr = 0.98 for uranium and;r = 0.78 for copper. Data did not permit statistical analysis of soil Pb versus plant Pb.

ISSN:0008-4026    

DOI:10.1139/b80-233

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Eight entomophilous plants, Aralia nudicaulis L., Clintonia borealis (Ait.) Raf.,Cornus alternifoliaL.,Cornus canadensisL.,Cornus stoloniferaMichx.,Kalmia angustifoliaL., Maianthemum canadense Desf., andViburnum trilobumMarsh., all of which bloom shortly after forest spray application in New Brunswick, were shown by bagging experiments to be dependent on insect visitation for seed set. All species showed significantly lower fecundity in fenitrothion-treated than in unsprayed areas. No depression of fecundity inClintonia borealisorKalmia angustifoliawas found associated with aminocarb (Matacil) spraying.

ISSN:0008-4026    

DOI:10.1139/b80-234

出版商:NRC Research Press    

年代:1980

数据来源: NRC

ISSN:0008-4026    

DOI:10.1139/b80-235

出版商:NRC Research Press    

年代:1980

数据来源: NRC