摘要:

The microfungal succession on the surfaces and interior of attached aspen poplar leaves was followed throughout a growing season at three heights in the tree canopy using a number of isolation and observational techniques. The fungal succession on and within the leaves was in general similar to that reported for other angiosperm leaves. The outer sheathing bud scales were colonized by a limited range of fungi, but the enclosed leaves were free from fungal colonization. The adaxial surfaces of young newly expanded leaves were sparsely colonized by fungi. As the leaves matured they were extensively colonized by the common phylloplane fungi (pink and white yeasts,Aureobasidium pullulans, Cladosporiumspp.,Alternaria alternata, andEpicoccum purpurascens) especially on the adaxial surface. At senescence both leaf surfaces had extensive hyphal growth on them and a greater internal colonization by phylloplane fungi had occurred. Common phylloplane fungi were less frequently isolated from freshly fallen leaves than from the senescent leaves, but a sterile dark species was frequently isolated from within them. The height of the leaves in the canopy was shown to influence the mycoflora of the aspen poplar leaves, with certain species (the yeasts,Aureobasidium pullulans, Cladosporiumspp., andBotrytis cinerea) showing changes in their frequency with sampling height.

ISSN:0008-4026    

DOI:10.1139/b79-332

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The vesicular–arbuscular mycorrhizal fungusGlomus mosseaewas examined by transmission electron microscopy and energy dispersive X-ray analysis. Electron-dense granules, found within vacuoles, were analyzed by X-ray analysis and found to contain high concentrations of phosphorus and calcium. These granules were similar in appearance to the polyphosphate granules described in other organisms. Highly vacuolated intercellular hyphae and vesicles possessed the greatest number of phosphorus granules. The granules were present in vacuolated arbuscular hyphae but absent from completely collapsed arbuscules. It was determined that the active arbuscule was the most probable site of breakdown of phosphorus granules. There were two other types of cellular inclusions, one vacuolar and one cytoplasmic, that could not be identified by X-ray analysis but that could easily be mistaken for phosphorus granules. It was concluded that general morphological appearance and location were not adequate criteria for the identification of phosphorus granules.

ISSN:0008-4026    

DOI:10.1139/b79-333

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Spring fires were conducted inSymphoricarpos occidentalisHook, stands to determine the effect of fire on the shrub and associated species. The canopy cover ofSymphoricarposhad recovered to the level of unburned stands 3 months after fire. Stem density increased three to five times in the first 3 months and then gradually declined during the 2nd and 3rd year.Rubus strigosusincreased in cover and stem density when burned and remained at higher levels for the 3 years studied. Forbs increased after fire with the cover of most annuals peaking the first growing season while perennials maintained a higher cover. The density of woody stems and coverage of the shrub, perennial forb, and grass and sedge groups continued to be higher 3 years after burning. There were substantial changes in one or more of frequency, cover, or density of major species.

ISSN:0008-4026    

DOI:10.1139/b79-334

出版商:NRC Research Press    

年代:1979

数据来源: NRC