摘要:

The Endomycetaceae is redefined and expanded to include yeasts and fungi bearing ascocarps or ascophores but is restricted to genera producing either galeate ascospores or other characteristics indicating affinities to the central genusCeratocystis. The genusEndomycesis emended and a neotype is selected for the type species,E. decipiens.Endomyces cortinariisp. nov. andPhialoascus borealisgen. et sp. nov. are described. A key to the genera admitted to the Endomycetaceae and listed below is included:Ambrosiozyma, Amorphotheca, Ascoidea, Botryoascus, Cephaloascus, Ceratocystiopsis, Ceratocystis, Endomyees, Europhium, Hansenula, Hormoascus. Pachysolen, Ophiostoma. Phialoascus, andStephanoascus.Zenderagen. nov. (Schizosaccharomycetaceae) andGalactomycesgen. nov. (Onygenaceae) are described. The following new combinations are made:Zendera tetrasperma(Macy et Miller) comb, nov.,Z. ovetensis(Peláez et Ramirez) comb, nov.,Galactomyces geotrichum(Butler et Petersen) comb. nov.,G. reesü(van der Walt) comb, nov., andMagnusiomyces magnusü(Ludwig) comb. nov.

ISSN:0008-4026    

DOI:10.1139/b77-198

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

A taxonomic study of the Triticeae at the generic level is needed for both practical and theoretical purposes. Many genera in this tribe contain species of prime importance to agriculture. It appears from many previous studies in many different disciplines, that the genera are very close to each other so that there are difficulties in properly defining them; but this very fact brings all the members of that group up to a high degree of importance for gene transfer purposes because of their close evolutionary relationships.The first paper in this series deals with the definition of 45 characters and their states, and evaluates their interrelationships and relative degree of importance for classificatory and diagnostic purposes. This is done through examination of conventional and new characters, and scrutinous verification of characters used hitherto by different authors in different areas at various times in the last 100 years. Analysis of the data was done using Estabrook's information theoretic model of character analysis and various other techniques, such as multidimensional scaling, principal component analysis, and clustering. It is concluded that no necessary correlation exists between the usefulness of a character for discriminating a particular genus and the value of the same character for distinguishing genera in the tribe and classifying them.

ISSN:0008-4026    

DOI:10.1139/b77-199

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Fifty-one species of Hepaticae and 210 species of Musci, a total of 261 species of bryophytes, are reported from Nahanni National Park and vicinity, southwestern District of Mackenzie, Northwest Territories, Canada. Of those, about 89 species are new to the District of Mackenzie and 11 species are previously unreported from the Northwest Territories.Among the phytogeographically significant species present in the bryoflora areMesoptychia sahlbergii(Lindb. & Amell) Evans,Molendoa obtusifoliaBroth. & Paris,Eucladium verticillatum(Brid.) B.S.G.,Scapania simmonsiiBryhn & Kaal.,Bryum wrightiiSull & Lesq.,Aulacomnium acuminatum(Lindb. & Amell) Kindb.,Tortella arcticaCrundw. & Nyholm,Didymodon johansenii(R. S. Williams) Crum,Entodon concinnus(De Not.) Paris,Ulota curvifolia(Wahlenb.) Lilj.,Bryobrittonia pellucidaR. S. Williams, andAndreaeobryum macrocarpumSteere & B. Murray.Hylocomium alaskanum(Lesq. & James) Austin is a name of convenience only and must be abandoned; it is merely a stunted physiological form ofH. splendens(Hedw.) B.S.G. that does not merit taxonomic recognition.

ISSN:0008-4026    

DOI:10.1139/b77-200

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

As the ovary wall develops, some similar events are seen in the dorsal and upper portions. These are as follows: (1) the deposition of many starch grains in most of the ground meristem cells; (2) considerable cell growth in most of the ground meristem cells; (3) the development of a thick outer wall on the outer protoderm of the ovary; and (4) elongation in the protoderm cells lining the inner part of the ovary. Unlike the upper ovary wall, starch grains appear in the outer protoderm cells of the dorsal ovary wall. A cytoplasmically dense layer of cells subjacent to the inner protoderm of the dorsal ovary wall continues to undergo cell division when other ground meristem cells are enlarging. This layer of cytoplasmically dense cells is the only recognizable layer in the ovary wall when the seed is mature. The ovule is bitegmetic, hemianatropous, and tenuinucellate. Integuments are protodermal in origin and both are mostly two cells thick. Cell division is more prolonged in the inner than in the outer integument and the inner layer of the inner integument develops safraninophilic granules in the cytoplasm of its cells. The outer integument is stretched and obliterated before the inner. As a result of faster growth in the basal end of the nucellus, the ovule undergoes a change in orientation from orthotropous to hemianatropous. Periclinal divisions are rare in the nucellar protoderm. The nucellus is eliminated by the time that the seed is mature. Megagametophyte development is normal and callose is associated with megaspores. Unlike most grasses, only three antipodals form but each antipodal is large and contains what appear to be many atypical nuclei. The endosperm initially lacks cell walls but they appear later in development. When the endosperm is cellular, its surface layer is meristematic. Starch grains are numerous in the endosperm cells and the cells have thick walls. The thick walls are a possible source of stored energy. A cuticle on the surface of the endosperm may serve a protective function. Different types of grass ovules are the result of different degrees of the same developmental phenomenon at comparable sites. Relationships as determined by cluster analysis of a similarity matrix based on detailed embryological data show that four members of the tribe Stipeae cluster together and this cluster is separate from a cluster consisting ofF. microstachysandAgrostis interrupta. Furthermore, the degree of similarity between the four stipeae was higher than that betweenF. microstachysandA. interrupta. This correlates well with the modem opinion thatFestucaandAgrostisare in separate tribes.

ISSN:0008-4026    

DOI:10.1139/b77-201

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

A celery-infecting isolate of aster yellows agent (isolate A), maintained in the greenhouse since its isolation from the field in 1958, was found to be significantly less transmissible by the aster leafhopper.Macrosteles fascifrons(Stål) than a similar isolate (isolate B) obtained from the same area in 1972. The difference in transmissibility was greatest in male insects, especially those given acquisition access periods as adults. Transmission of isolate A was increased to equal that of isolate B when leafhoppers were injected with inocula prepared from inoculative leafhoppers. No differences were found between isolates in their incubation periods in plants and insects or in their ability to infect asters. On the basis of earlier data and present findings, it is suggested that isolate A has undergone a change in transmissibility during its maintenance in plants grown under artificial conditions.

ISSN:0008-4026    

DOI:10.1139/b77-202

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

11C fed to leaves as11CO2was used to study the dynamics of short-term translocation of photosynthate inHelianthus. As in14C studies small amounts of tracer were often detected in the stem close to the fed leaf in the first 5 min, followed by a larger mass flow after 15 min. The speed of mass flow of tracer movement was calculated to be 60 to 400 cm ∙ h−1depending on the method of calculation. There was no evidence in the premass flow for discrete spots along the stem or petiole where tracer accumulated. Neither was there firm evidence for pulses of tracer moving steadily forward, but there were point fluctuations of greater variability than would be expected by chance alone, which suggest the possibility of abberations of movement superimposed on the mass flow. Details of these abberations could not be assessed with certainty from these preliminary experiments owing to the rather low tracer activity.The translocation profiles were sensitive to the prior light conditioning of the plant and above all to chilling. InHelianthusthe latter produced temporary restrictions in translocation which lasted for some 10–12 mi

ISSN:0008-4026    

DOI:10.1139/b77-203

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Ten strains ofChlamydomonas reinhardtiiflagellar mutants were successfully cryopreserved using two cryogenic freezing methods. Dimethylsulfoxide (DMSO) was found to be the only effective cryoprotectant of those tested. After recovery, cells were viable and morphologically indistinguishable from non-frozen cells. No recovery was obtained after lyophilization.

ISSN:0008-4026    

DOI:10.1139/b77-204

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Cytochalasin B, auxin, and colchicine elicit rapid cytoplasmic weakening in oat coleoptiles as evidenced by centrifugal displacement of nuclei. Cytochalasin B, applied in combination with colchicine or auxin, produced approximately additive effects. In contrast, combination of auxin and colchicine elicited a mutually antagonistic interaction.

ISSN:0008-4026    

DOI:10.1139/b77-205

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Although no host-specific toxin, nor a great quantity of any toxic substance, has been found in culture filtrates of 26 different isolates ofHelminthosporium sativum, the amount of the toxic metabolite, victoxinine, produced by these strains, may be correlated generally to their aggressiveness towards wheat.

ISSN:0008-4026    

DOI:10.1139/b77-206

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The nature of the peridial deposits in the genusPerichaenaand in a species ofDianemahas been defined by a combination of scanning electron microscopy, x-ray microanalysis, and various chemical techniques. These crystalline deposits in the peridium have proven to be primarily calcium oxalate. Some species ofPerichaenaand theDianemaalso incoiporate silicon crystals on the peridium. The white and non-white phases of different species ofPerichaenawere compared and found to have similar elemental composition of peridia.

ISSN:0008-4026    

DOI:10.1139/b77-207

出版商:NRC Research Press    

年代:1977

数据来源: NRC