摘要:

Trechispora alnicola(Bourd. & Galz.) Liberia was associated withPoa pratensisL. roots and in the thatch layer of blue-grass sod. These plants had yellowed leaves. On thatch and culture medium, the fungus isolated from diseased plants produced hyaline mycelium typical ofT.alnicola, and crystalline material. Conidia produced on thatch or on culture medium germinated by the production of a single germ tube. Basidia from basidiomata produced in nature were arranged in an effused manner; basidiospores were echinulate. This is the first report ofT.alnicolaassociated with a member of the Graminae.

ISSN:0008-4026    

DOI:10.1139/b87-021

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Morphology, ultrastructure, and some aspects of the chemical composition of a fibrillar sheath surrounding cells of the fungusAscocalyx abietina(Lagerberg.) Schlaepfer-Bernhard were studied using electron microscopy and gold-labeled ligands. Although consistently present around all cells, the fibrillar matrix was found to vary greatly in morphology within the same isolate, depending apparently on age and (or) physiological conditions of the cells. Around cells considered younger, the sheath appeared always to be constituted of fibrillar masses that varied in size and shape but were delineated by a well-defined border. In contrast, cells expected to be older were generally bordered by a regular and uniform matrix composed of numerous intertwined fine fibrils, some being associated with small osmiophilic knobs. The presence of RNA in the denser layers of the sheath was revealed through gold complexes with either RNase A or RNase B. Continuity of portions of the sheath with similar material surrounding endocells or intact cells through gaps in the wall was frequently observed. This observation was considered as one of the possible explanations for the presence of RNA in the sheath. Association of sugars such as β-glucopyranosides and especially sialic acid with the extracellular matrix is, most probably, relevant to specific biological functions such as attachment to host cells, protection against unfavourable physical conditions and transport of cationic compounds. Peculiarities of this sheath produced byA.abietinacontribute, therefore, to distinguish it from those described in other fungi.

ISSN:0008-4026    

DOI:10.1139/b87-022

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

The fungusAscocalyx abietina(Lagerberg.) Schlaepfer-Bernhard, the scleroderris canker agent of conifers, is composed of a regularly septate mycelium, often branched at divergent angles. All fungal cells appear delimited by a thick wall surrounded by a dense fibrillar network. Peculiar ultrastructural characteristics of this fungus were observed, such as irregular nuclei with multishaped blebs and endoplasmic reticulum oriented in definite parallel arrays. Presence of single or multiple endocells was frequently observed. In some instances, gaps were present in the walls of enclosing cells where the cytoplasmic contents had escaped. Amylase, chitinase, β-galactosidase, lipase, and cellulose–gold complexes were used to localize various substances inA.abietinacells. With such complexesN-acetyl-D-glucosamine, β-galactosides, and lipids were detected in the cell walls, while glycogen deposits were found to occur in cytoplasmic electron-transparent bodies. The present work presents the ultrastructural features ofA.abietinaand adds to some of the cytochemical aspects recently reported.

ISSN:0008-4026    

DOI:10.1139/b87-023

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

The response of net CO2exchange to thallus water content, thallus temperature, and photosynthetically active radiation was measured in the laboratory for two morphologically different forms ofRamalina menziesiicollected from a coastal and an inland habitat in central California. Equations describing the response curves are fitted to the data and compared statistically for the two sites during two seasons. Significant differences were present for all responses both in summer and winter but were more pronounced for net photosynthesis than for dark respiration. The main differences between the two forms were in the absolute rates of net photosynthesis; a maximum of 6.2 was measured for the inland form but only 3.6 mg∙g−1∙h−1for the coastal form. Chlorophyll contents were also different between the two forms, indicating that chlorophyll is the likely cause for the difference in net photosynthetic rates. Net photosynthetic rates were higher at low temperatures during winter than during summer, but otherwise seasonal variations in the gas exchange responses were relatively minor. Both forms of the lichen are light saturated at quantum fluxes greater than 200 μE∙m−2∙s−1. Both show an optimum temperature for maximum CO2exchange at 25 °C, well above the mean operating temperature ofR.menziesiiin th

ISSN:0008-4026    

DOI:10.1139/b87-024

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Protoplasts isolated from petioles and stems of two varieties of sweet potato showed high plating efficiency, and rhizogenic calli were obtained. The yield of protoplasts and the rate of survival of cell division were statistically analysed. Results are discussed in relation to the identification of different protoplast subpopulations and their histological origin.

ISSN:0008-4026    

DOI:10.1139/b87-025

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Soluble protein extracts from 19 isolates ofChaetomiumwere subjected to isoelectric focusing in polyacrylamide gel rods. The isoelectric point (pI) values of esterase isoenzymes were determined and the data used to calculate coefficients of similarity. Isolates ofC.aureumandC.trilateralewere electrophoretically distinct, whereas isolates ofC.confusum,C.humicola,C.rubrogenum, andC.trilateralewere not distinguishable electrophoretically from each other. The profiles A, B, F, and G can be used to distinguish the species ofC.atrobrunneum,C.aureum,C.cupreumandC.fusiforme. These results partly agreed with the morphologically based classification of theC.aureumspecies group. Certain esterase bands were found to be useful as diagnostic markers for differentiatingChaetomiumspecies.

ISSN:0008-4026    

DOI:10.1139/b87-026

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

New species ofWrightoporiaPouz. from Africa and Asia have features that overlap the limits ofAmylonotusRyv. We found dextrinoidicity, wall coloration of the skeletal hyphae, and the general morphology of the fruit bodies to be variable features in both genera. Gloeopleurous hyphae and gloeocystidia or pseudocystidia occur in all species of these genera so far studied. The synonymy ofAmylonotuswithWrightoporiais proposed. The following new taxa are described:Wrightoporia dimidiataDavid & Rajch.,W. gillesiiDavid & Rajch., andW. ramosaDavid & Rajch. Two new combinations are proposed:W. flava(Ryv.) David & Rajch. andW. ochrocrocea(Henn. & Nyman) David & Rajch.;W. pouzariiDavid & Rajch. is a new name forA.africanusRyv. Cultural characters ofW.flava(Ryv.) David & Rajch.,W.gillesiiDavid & Rajch., andW.tropicalis(Cke.) Ryv. are described. The position ofW.cylindrosporaRyv. andW.tropicalis(Cke.) Ryv. in the context of the genus and the relationships ofAmylosporusRyv.,HeterobasidionBref., andWrightoporiaPouz. are discussed.RigidoporopsisJohans. & Ryv. is considered a synonym ofAmylosporusRyv.

ISSN:0008-4026    

DOI:10.1139/b87-027

出版商:NRC Research Press    

年代:1987

数据来源: NRC

摘要:

Soil pH and concentrations of N and P in leaves ofDryas drummondiiwere measured on recessional moraines of the Athabasca Glacier, Alberta. Soil pH declined by 0.5 units per 100 years underDryasbut remained steady on bare ground. Water-soluble N and P levels in soil remained low at all stages, but N was higher underDryaspatches. Leaf P and N declined in the early stages of succession but increased later. This increase may represent the initiation of biotic N and P cycles in soil. These patterns contrast with those reported for other moraine successions.

ISSN:0008-4026    

DOI:10.1139/b87-028

出版商:NRC Research Press    

年代:1987

数据来源: NRC

ISSN:0008-4026    

DOI:10.1139/b87-029

出版商:NRC Research Press    

年代:1987

数据来源: NRC