摘要:

Phellinus weiriiis a heterothallic basidiomycete lacking clamp connections. Compatible pairings of single-spore isolates have a changed colony morphology, faster growth, and fewer nuclei per cell than the single-spore isolates alone. Compatible pairings occasionally form basidiocarps in culture. Single-spore isolates from different fruiting bodies are sexually compatible; most single-spore isolates from the same fruiting body are incompatible. Vegetative incompatibility is manifested by a line of demarcation formed when two dissimilar heterokaryotic isolates meet. Line formation is a sensitive indicator of genetic differences between heterokaryons or between heterokaryons and homokaryons.

ISSN:0008-4026    

DOI:10.1139/b79-195

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Phellinus weiriiproduces uninucleate basidiospores, a multinucleate, homokaryotic mycelium (mean of 3.2 nuclei per cell), and an irregularly binucleate, heterokaryotic mycelium (mean of 2.2 nuclei per cell). Homokaryons grow more slowly and appear more uniform in culture than heterokaryons, and do not form basidiocarps in culture. Homokaryotic and heterokaryotic isolates could be reliably distinguished using the combined characteristics, but not using any one character alone. Thirty isolates from infected trees were heterokaryotic, although numbers of nuclei were less regular than for isolates from basidiocarps.

ISSN:0008-4026    

DOI:10.1139/b79-196

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

A study of the effects of fluoride emissions (HF, SiF4) on certain species of bryophytes was carried out in the vicinity of an industrial plant producing elemental phosphorus at Long Harbour, Nfld. Damage symptoms varied from mild phyllid chlorosis (yellowing) to severe browning of up to 95% of the phyllids.Polytrichum communeHedw. was the main bryophyte species used in the survey. Random collections from 45 sample sites were analysed for total fluoride. The fluoride concentrations in phyllid tissue ranged from a high of 6066 ppm (dry weight) at a distance of 1 km northeast of the emission source to 44 ppm (dry weight) 1 1.7 km northeast of the emission source in the direction of the prevailing wind. Control samples were obtained from similar sites in areas far removed from the industrial plant and contained, on average, 11.3 ppm (dry weight). The concentration of fluoride in the bryophyte phyllid tissue was inversely correlated with distance from the emission source, in the direction of the prevailing wind. The severity of acropetal scorching was found to be correlated with the concentration of fluoride in the bryophyte phyllid tissue, and in addition, samples high in fluoride had fewer sporophytes. Fluoride concentrations in bryophyte tissue are compared with concentrations of fluoride in the needles of balsam fir,Abies halsameaL., in four damage zones, and also with available and total fluoride in soil humus and concentrations of fluoride in air. The total area affected by fluoride emissions was increased using bryophytes as the pollution indicator species, especially in areas far from the industrial plant.

ISSN:0008-4026    

DOI:10.1139/b79-197

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

A listing of some 330 algal taxa found in the plankton of the Bay of Quinte during 1975 has been compiled and an indication given of the relative abundance at each of the eight sampling locations. Some difficulties related to interpretation of data on species number or 'richness' are discussed. It is suggested that particular attention in future years be given to several little-known taxa whose distribution and abundance will likely change should the trophic state of the Bay of Quinte be altered. Several species found in the Quinte collections have been only rarely reported from other parts of the world. Taxonomic notes on some problematical or otherwise interesting forms are included.

ISSN:0008-4026    

DOI:10.1139/b79-198

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Comparisons were made of the soil fungi isolated from three diverse alpine sites. The sites studied were a grass slope (Bromusassociation) at 1900 m, an alpine meadow (Dryasassociation) at 2530 m, and a summit ridge (Oxytropisassociation) at 2840 m. The effects of season, soil depth, and substrate type on the distribution of fungi were also examined. In a principal component analysis, most of the variation in mycoflora composition was attributed to differences among the sites. All taxa tested using a factorial analysis of variance showed significant differences in isolation frequency among the three sites. About half showed significant variation with season. For total fungi, the effect of seasonal change was the smallest of the four factors studied. Seasonal changes were not unidirectional, instead the composition of the fungal community shifted to one extreme in summer, with the direction of this change later reversing to another extreme in the fall opposite to that of the summer. The frequency of occurrence of most taxa was inversely related to soil depth. However,Chrysosporium pannormn, Penicillium restrictum. Penicillium canescens, and sterile fungi showed the opposite trend.The fungal communities were characterized by a few frequently isolated species, and a much larger proportion of infrequently isolated forms. All the dominant species were also widely distributed in temperate soils. The less frequently isolated species were usually highly aggregated in their distribution, with localized densities often exceeding those of the most frequently isolated forms. This pattern of distribution may have resulted from specialization on a niche dimension that was not widely distributed in the soils studied. Dominant species were less aggregated and more widely distributed, possibly reflecting a broad or diverse niche space for these species.

ISSN:0008-4026    

DOI:10.1139/b79-199

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The community structure and interactions among the soil microfungi of three alpine sites were investigated using a factor analytical method. The sites were distributed along an elevation gradient, and the diversity and evenness of allotment of species were inversely related to altitude. Clusters of species having similar distributions were defined from factor analyses performed separately for each site. Within each site, differences among the soil horizons were primarily responsible for variation in the fungal community, and species groups were differentiated by their patterns of colonization of the soil profile. Changes in the mycoflora with depth were continuous, although the magnitude of these changes was greater near the surface of the soil. Seasonal changes also were most apparent in the surface horizons.In a grassland site at 1900 m, a species group dominated byPenicillium janthinellumwas largely restricted to the surface horizons of the soil, and three other species groups were affected by seasonal changes in the environment. In an alpine meadow site (2530 m), thePenicillium steckiiandCylindrocarpon destructansgroups occurred in the surface horizons, with the first group predominant in the spring and the second in the summer and fall. At a summit ridge site (2840 m), all taxa except the sterile fungi were essentially restricted to the surface horizons. Species groups dominated by sterile-dark fungi were predominant in the bottom horizons at all three sites.The most frequently occurring species usually had large communalities indicating a high degree of association with the other species, and probably reflecting their influence over the suitability of the environment for exploitation by other species. The communality structure also indicated a decrease in species interactions with increasing depth of soil.

ISSN:0008-4026    

DOI:10.1139/b79-200

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Temperature, moisture, available potassium, and soil pH were the most important abiotic variables influencing the distribution and community composition of soil fungi from three diverse alpine habitats. The major differences in species composition occurred among the sites. An ordination contrasting the sites, based on the species composition of the mycoflora, was correlated with a gradient contrasting temperature and moisture with potassium. The observed differences in species composition among the sites were concluded to have resulted from conflicting demands on the species for efficiency and adaptability. Relatively few species were isolated from the more exposed summit ridge site (2840 m). and these were probably genetically diverse species capable of adapting to environmental extremes. Alternatively, dominant species may be specialists adapted to limiting dimensions that are widely distributed in the environment. Dominant species at the drought-prone grassland site (1900 m) appeared adapted to low moisture, and those of the alpine meadow site (2530 m) to low temperature.Seasonal changes in mycoflora composition were related to changes in the moisture and temperature status of the soils, with low temperature limiting in the spring and low moisture in the fall.Chrysosporium pannorumandPenieillium janthinellumwere adapted to combined low temperature and moisture.Cylindroearpon didymuin, Glioeladium deliquescens, Fusarium merismoides. Penicillium steckii, andCylindrocarpon destructansoccurred only in soils with a relatively high temperature–moisture status. Changes in mycoflora composition with soil depth were attributed to an environmental gradient combining temperature, moisture, and K without contrasts. Sterile fungi, apparently adapted to the adverse conditions of low temperature. moisture, and K. were dominant in the lower horizons at all three sites. Soil K appeared to be a limiting factor for many species restricted to the surface horizons, including the frequently isolated speciesFusarium acuminatum. Penicillium janthinellum. Penicillium simplicissimum. Penicillium steckii. Phoma eupyrena. andTrichoderma liamatum.

ISSN:0008-4026    

DOI:10.1139/b79-201

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Strasseria geniculata(Berk. & Br.) Höhn. is described and illustrated for the first time from North America. The hosts, all in Pinaceae, are new records:Abies balsameaL.,Picea glauca(Moench) Voss,Pinus resinosaAit., andP. sylvestrisL. Some comments on conidial formation are offered and 12 species ofStrasseriaon 11 host families are listed.

ISSN:0008-4026    

DOI:10.1139/b79-202

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Breeding experiments were performed with pure lines ofAvena fatuadiffering characteristically in duration of primary seed dormancy. The results indicate that the parental lines differ for at least three genes controlling rate of afterripening. It is evident that at least two of these genes influence the rate of afterripening at different periods after seed maturation.

ISSN:0008-4026    

DOI:10.1139/b79-203

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Two techniques were evaluated for detecting sexual and aposporous embryo sacs in an apomictic grass. Pistils ofCenchrus ciliarisL. were fixed in formalin – acetic acid – alcohol (FAA), cleared in methyl salicylate, and examinedin totoby interference contrast microscopy. The same pistils were then embedded in plastic, sectioned, and studied by conventional microscopy. The two methods yielded identical interpretations of embryo sac morphology. The cleared-pistil technique was simple and required about 1/10 the time of the sectioning method.

ISSN:0008-4026    

DOI:10.1139/b79-204

出版商:NRC Research Press    

年代:1979

数据来源: NRC