摘要:

Revisionary studies of the anamorph-genusStrasseriahave led to the recognition of a single species:Strasseria geniculata, the synonymy of which is expanded to includeS. carpophilaf.pruni, S. oxycocci, S. nigra,andS. rhododendri.Strasseria aconitiis reduced to synonymy withNeoplaconema napelli. Strasseria agapanthi, S. camarae, S. corynocarpi, S. garciniae, S. japonica, S. petrakii, S. phomopsimorpha, S. polygonati, S. rusci, S. sequoiae, S. viburni, andS. vincaeare shown to belong inPhyllosticta. Strasseria dar-akobensisis excluded fromStrasseria. Strasseria lycopodina, Ceuthospora lunata, and three previously undescribed coelomycetous anamorphs are disposed in a new anamorph-genus:Apostrasseria. Nothostrasseriaanam.-gen. nov., type species:N. dendritica(≡Spilomyces dendritica)is erected for a fungus on leaves ofEucalyptus eximia, E. maculata, andE. obliquain Australia.

ISSN:0008-4026    

DOI:10.1139/b83-001

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

An emendation of the Phacidiaceae is presented. Of 24 genera placed in the family by previous authors, only 2,LophophacidiumandPhacidium(=Phacidiostroma) are retained. Four new species are described, and three new combinations made, inPhacidium. TheApostrasseriaorCeuthosporaanamorphs of six of these are also described.Phacidium symplocinumis made the type species of a new genus,Ascluella, tentatively maintained in the Dermateaceae. The new combinations,Coccomyces gaultheriae, Odontotrema sieversiae, Pseudophacidium kumaonense, andSchizoxylon hemisphaericum, are introduced.

ISSN:0008-4026    

DOI:10.1139/b83-002

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

Light and transmission electron microscopy were used to characterize representative stages of sporogenic plasmodia and resting spores of the plasmodiophorid parasite in roots ofHeteranthera dubia(Jacq.) MacM. (water-stargrass). Cruciform nuclear divisions occurred in young plasmodia and noncruciform divisions occurred in more mature, transitional plasmodia. Prophase nuclei in transitional plasmodia contained synaptonemal complexes; noncruciform divisions were interpreted, therefore, as meiosis. Host–parasite interfaces were single unit membranes. Centrioles were paired end-to-end in plasmodia, but unpaired, single centrioles were in resting spores. Resting spores also contained crystalline bodies. Sporosori were disklike, consisted predominantly of single layers of resting spores, and were located at the periphery of host cells.Membranosorus heterantheraeOstenfeld and Peterson was considered the appropriate genus–species for the parasite, notSorodiscus heterantheraeWernham.

ISSN:0008-4026    

DOI:10.1139/b83-003

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

The pollen grains ofBerendtiellaandHemichaenaare single, isopolar, and tricolporate with a microreticulate to reticulate sexine 2. Intra- and inter-specific variability in pollen characters are assessed statistically, and preliminary evaluation of the taxonomic utility of these data is presented. The bearing of the pollen evidence on proposed intratribal categories and the transfer of the genera from the tribe Scrophularieae (Cheloneae) to the tribe Mimuleae are discussed. The proposed close relationship between the genera and the transfer ofDiplacus rugosatoBerendtiellaare consistent with the pollen data, but suggested affinities betweenBerendtiellaandDiplacusclearly are not. The grains ofBerendtiellaandHemichaenaresemble the type II pollen ofMimulus, and the uniformity of pollen morphology in members of the Mimuleae other thanMimuluslends support to the recognition of segregate genera in the latter palynologically diverse genus.

ISSN:0008-4026    

DOI:10.1139/b83-004

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

The accumulation of Cu, Ni, Zn, Fe, Mn, Mg, and Ca in tissues ofTypha latifoliaalong a 76-km transect extending northwest from Sudbury, Ont., was investigated. Despite high levels of Cu and Ni in the soil–sediment material, these metals were largely excluded from aboveground tissues ofT. latifolia. Concentrations of Fe in tissues ofT. latifoliawere unusually low and may reflect induced iron deficiency. The patterns of uptake of all the metals (except Ca) were similar. Roots showed higher concentrations than the rhizomes and aboveground parts and young leaf tissue (leaf bases) showed lower concentrations than older leaf tissue (leaf tips). Concentrations of Zn, Mg, and Ca accumulated in tissues ofT. latifoliawere not correlated with soil–sediment metal concentrations. Concentrations of Cu and Ni in belowground and reproductive tissues were correlated with soil–sediment concentrations; however, concentrations in the leaves were not. Accumulation of Fe and Mn in all plant tissues was correlated with concentrations in the soil–sediment material. Soil–sediment pH,Eh, and organic carbon content may have affected the uptake of metals byT. latifolia. However, the effects of any of these factors in isolation may have been obscured by the variation in other physical or biotic factors.

ISSN:0008-4026    

DOI:10.1139/b83-005

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

Some observations and experiments were carried out on inflorescences of wild oats,AvenafatuaL. (Poaceae). Results of these studies indicate that the distal spikelets are initiated and mature earlier than those in the proximal positions. In each spikelet, the primary floret matures earlier than the secondary floret. However, the less mature secondary floret drops from the spikelet sooner. The awn in mature florets is geniculate and shows a characteristic twisting movement depending on the availability of moisture in the atmosphere. The movement of awns results in periodic dislodging of mature florets from spikelets. The basipetal maturity of spikelets in the panicle, the acropetal maturity of florets in each spikelet, and the premature separation of florets aided by the awn movement produce caryopses of variable maturity and are of considerable significance in the reproductive biology of wild oats.

ISSN:0008-4026    

DOI:10.1139/b83-006

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

Six mycorrhizal and three saprophytic fungi were collected. They were cultivated in a liquid medium with or without a deficiency in phosphate. Different phosphatase activities were measured from the mycelia: phosphatase activities accessible to an external substrate, phosphatase activities in the culture medium, phosphatase activities of the whole homogenate and two parts of this homogenate (parietal and soluble). With both the mycorrhizal and saprophytic fungi, the deficiency in inorganic phosphate induced a large increase in phosphatase activities which were multiplied on the average by a factor of 72, 56, 43, 64, and 26, for the excreted, accessible, total, parietal, and soluble activities, respectively. If the relative proportions of the various activities were considered, the parietal activity, compared with the total phosphatase activity, increased in six out of nine cases under the effect of phosphate deficiency. The superiority of the parietal activity over the soluble activity was either induced by phosphate deficiency or preexisting. The accessible activity represented only a fraction of the parietal activity and this was usually smaller in a phosphate-deprived medium. Various criteria have been considered to class these fungi in terms of their response to phosphate deficiency, such as the intensity of their phosphatase response to the deficiency and the absolute values in a phosphate-deprived medium of various phosphatase activities. These various criteria do not lead to a classification entirely parallel of the different fungi and they do not discriminate between mycorrhizal and saprophytic fungi.

ISSN:0008-4026    

DOI:10.1139/b83-007

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

There are three successive phases to foliolar development inParkinsonia aculeata: (i) an initial phase during which primordium formation occurs; (ii) a morphogenic phase, with foliole formation; (iii) a histogenic and differentiation phase, with foliole development. Foliolar shape is determined during the basic morphogenic phase; a longer phase in which a zoning effect analogous to that seen in branches has been observed: (i) a zone of distal organ formation where folioles appear in constant succession, in a specific location, and in close proximity of each other along each border (these are the three criteria which define intrafoliolar generation centres); (ii) a histogenic median zone; and if the foliole is old enough (iii) a subproximal differentiation zone; (iv) an adult proximal zone.

ISSN:0008-4026    

DOI:10.1139/b83-008

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

Nodule structure, nodule enzymes of ammonia assimilation, nodule phosphoenolpyruvate carboxylase, nitrogenase-dependent acetylene reduction, and soluble protein were studied in four plant-determined ineffective genotypes and in one effective genotype of alfalfa (Medicago sativaL.) grown in a glasshouse. Ineffective nodules that formed on genotypes MnAg(In) and MnSa(In) were similar to effective nodules in early development. However, these nodules had smaller bacteroids and senesced much more rapidly than effective nodules. In contrast, nodules that formed on ineffective genotypes MnNC-3226(In) and MnNC-3811(In) were tumorlike and had few infection threads and bacteroids, and host cells were filled with starch. Nodules from plant-determined ineffective genotypes had reduced glutamine synthetase, glutamate synthase, phosphoenolpyruvate carboxylase, and nodule soluble protein when compared with effective nodules. There were differences between genotypes for all biochemical parameters assayed.

ISSN:0008-4026    

DOI:10.1139/b83-009

出版商:NRC Research Press    

年代:1983

数据来源: NRC

摘要:

Four families of diatoms, well represented in the ice microflora of Manitounuk Sound, Hudson Bay, are treated. The Entomoneidaceae (Entomoneis, 6 taxa;Plagiotropis, 2 taxa) and the Nitzschiaceae (Nitzschia, 12 taxa) have more representatives than the Cymbellaceae (Amphora, 1 taxon) and the Gomphonemataceae (Gomphonema, 2 taxa). Taxonomic information is given for these 23 taxa by means of complete illustrated descriptions. One species and one variety are described as new in the genusNitzschia, and new nomenclatural combinations are proposed for the six taxa ofEntomoneisand the two ofPlagiotropis.

ISSN:0008-4026    

DOI:10.1139/b83-010

出版商:NRC Research Press    

年代:1983

数据来源: NRC