Microfungal succession on living leaves of Populus tremuloides

1979 ◽  
Vol 57 (24) ◽  
pp. 2800-2811 ◽  
Author(s):  
H. G. Wildman ◽  
D. Parkinson
Keyword(s):  
Populus Tremuloides ◽  
Aureobasidium Pullulans ◽  
Hyphal Growth ◽  
Limited Range ◽  
Tree Canopy ◽  
Fungal Colonization ◽  
Phylloplane Fungi ◽  
Sampling Height ◽  
Fallen Leaves ◽  
Poplar Leaves

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, Cladosporium spp., Alternaria alternata, and Epicoccum 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, Cladosporium spp., and Botrytis cinerea) showing changes in their frequency with sampling height.

Quantification of fungal colonization in modified wood: Quantitative real-time PCR as a tool for studies on Trametes versicolor

Holzforschung ◽  
2010 ◽  
Vol 64 (5) ◽  
Author(s):  
Annica Pilgård ◽  
Gry Alfredsen ◽  
Ari Hietala
Keyword(s):  
Real Time ◽  
Trametes Versicolor ◽  
Growth Period ◽  
Hyphal Growth ◽  
Growth Patterns ◽  
White Rot ◽  
White Rot Fungus ◽  
Fungal Colonization ◽  
Wood Preservatives ◽  
Fungal Dna

Abstract Traditional wood preservatives based on biocides are effective against wood-deteriorating organisms because of their toxicity. By contrast, modified woods are non-toxic by definition. To investigate the efficiency of various wood modifications, quantitative real-time polymerase chain reaction (qPCR) was used to profile the DNA amounts of the white-rot fungus Trametes versicolor (L.) [Lloyd strain CTB 863 A] during an 8-week-long growth period in treated Pinus sylvestris (L.) sapwood. The studied wood was modified by acetylation, furfurylation, and thermal treatment. The traditional wood preservatives bis-(N-cyclohexyldiazeniumdioxy)-copper (Cu-HDO) and chromated copper arsenate (CCA) were used as references, whereas untreated P. sylvestris (L.) sapwood served as a control. The maximum levels of fungal DNA in native wood occurred at the end of the experiment. For all wood treatments, the maximum fungal DNA level was recorded after an incubation period of 2 weeks, followed by a decline until the end of the trial. For the preservative-treated woods, Cu-HDO showed the lowest level of fungal DNA throughout the experiment, indicating that exploratory hyphal growth is limited owing to the phytotoxicity of the treatment. The other treatments did not inhibit the exploratory hyphal growth phase. We conclude that qPCR studies of hyphal growth patterns within wood should provide a powerful tool for evaluating and further optimizing new wood protection systems.

scholarly journals Spray Drift from Three Airblast Sprayer Technologies in a Modern Orchard Work Environment

2019 ◽  
Vol 64 (1) ◽  
pp. 25-37 ◽  
Author(s):  
Edward J Kasner ◽  
Richard A Fenske ◽  
Gwen A Hoheisel ◽  
Kit Galvin ◽  
Magali N Blanco ◽  
...  
Keyword(s):  
Wind Speed ◽  
Work Environment ◽  
New Technologies ◽  
Distance Sampling ◽  
Tree Canopy ◽  
Spray Drift ◽  
Axial Fan ◽  
Exposure Pathway ◽  
Sampling Height ◽  
The Impact

Abstract Pesticide spray drift represents an important exposure pathway that may cause illness among orchard workers. To strike a balance between improving spray coverage and reducing drift, new sprayer technologies are being marketed for use in modern tree canopies to replace conventional axial fan airblast (AFA) sprayers that have been used widely since the 1950s. We designed a series of spray trials that used mixed-effects modeling to compare tracer-based drift volume levels for old and new sprayer technologies in an orchard work environment. Building on a smaller study of 6 trials (168 tree rows) that collected polyester line drift samples (n = 270 measurements) suspended on 15 vertical masts downwind of an AFA sprayer application, this study included 9 additional comparison trials (252 tree rows; n = 405 measurements) for 2 airblast tower sprayers: the directed air tower (DAT) and the multi-headed fan tower (MFT). Field-based measurements at mid (26 m) and far (52 m) distances showed that the DAT and MFT sprayers had 4–15 and 35–37% less drift than the AFA. After controlling for downwind distance, sampling height, and wind speed, model results indicated that the MFT [−35%; 95% confidence interval (CI): −22 and −49%; P < 0.001] significantly reduced drift levels compared to the AFA, but the DAT did not (−7%; 95% CI: −19 and 6%; P = 0.29). Tower sprayers appear to be a promising means by which to decrease drift levels through shorter nozzle-to-tree canopy distances and more horizontally directed aerosols that escape the tree canopy to a lesser extent. Substitution of these new technologies for AFA sprayers is likely to reduce the frequency and magnitude of pesticide drift exposures and associated illnesses. These findings, especially for the MFT, may fit United States Environmental Protection Agency’s Drift Reduction Technology (DRT) one-star rating of 25–50% reduction. An ‘AFA buyback’ incentive program could be developed to stimulate wider adoption of new drift-reducing spray technologies. However, improved sprayer technologies alone do not eliminate drift. Applicator training, including proper sprayer calibration and maintenance, and application exclusion zones (AEZs) can also contribute to minimizing the risks of drift exposure. With regard to testing DRTs and establishing AEZs, our study findings demonstrate the need to define the impact of airblast sprayer type, orchard architecture, sampling height, and wind speed.

Ectomycorrhizal colonization of greenhouse-grown Douglas-fir (Pseudotsuga menziesii) seedlings by inoculum associated with the roots of refuge plants sampled from a Douglas-fir forest in the southern interior of British Columbia

2004 ◽  
Vol 82 (6) ◽  
pp. 742-751 ◽  
Author(s):  
Shannon M Hagerman ◽  
Daniel M Durall
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Populus Tremuloides ◽  
Arbuscular Mycorrhizal ◽  
Douglas Fir ◽  
Fungal Colonization ◽  
Inoculum Potential ◽  
Paper Birch ◽  
Salix Bebbiana ◽  
Ectomycorrhizal Morphotypes

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were grown in the greenhouse in a sterilized mixture of forest soil and vermiculite, which had been inoculated with root fragments from one of six different ectomycorrhizal under story plant species (Arctostaphylos uva-ursi (L.) Spreng, P. menziessi, Salix bebbiana Bebb, Alnus viridis subsp. sinuata (Regel) Ä. Löve & and D. Löve (alder), Betula papyrifera Marsh. (paper birch), Populus tremuloides Michx.) and arbuscular mycorrhizal Calamagrostis rubescens Buckl. (pinegrass) sampled from a dry Douglas-fir forest in the southern interior of British Columbia. The overall objective of the present study was to investigate the inoculum potential of these ectomycorrhizal roots for colonizing Douglas-fir seedlings. A total of seven ectomycorrhizal morphotypes formed on the bioassay seedlings, which were colonized by all treatments except the control. Seedlings growing in soil inoculated with root fragments of Douglas-fir, Arctostaphylos, and paper birch had greater ectomycorrhizal richness and a higher percentage of colonized fine roots relative to the pinegrass and alder treatments. The community of ectomycorrhizal fungi that colonized the bioassay seedlings differed from that associated with some of the same refuge plants assessed in a previously reported field-based study at this site. Different ectomy corrhizal fungal colonization strategies and the retention of refuge plants are discussed in relation to the colonization of outplanted seedlings following clearcutting.Key words: ectomycorrhizae, refuge plants, inoculum potential, soil bioassay, Pseudotsuga menziesii.

Seasonal changes in water-soluble carbohydrates of Populus tremuloides leaves

1981 ◽  
Vol 59 (5) ◽  
pp. 862-869 ◽  
Author(s):  
H. G. Wildman ◽  
D. Parkinson
Keyword(s):  
Populus Tremuloides ◽  
Seasonal Changes ◽  
Tree Canopy ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Leaf Leachate ◽  
Leaf Surfaces ◽  
Microbial Development ◽  
Poplar Leaf ◽  
Sampling Times

Leaf leaching was simulated by washing leaves in distilled water. A variation in the quality and quantity of aspen poplar leaf leachate carbohydrates with respect to season and height in the tree canopy was observed. Some carbohydrates were subject to less variation than others. Fructose was the major component of the leachate carbohydrate at all sampling times. Other carbohydrates occurring in the leachate included glucose, galactose, inositol, sucrose, maltose, raffinose, an unknown 12-C, and an unknown 18-C carbohydrate. The possibility that restricted availability of total and (or) particular carbohydrates may play a role in controlling microbial development on leaf surfaces is discussed.

scholarly journals Spilocaea oleagina in Olive Groves of Southern Spain: Survival, Inoculum Production, and Dispersal

Plant Disease ◽  
2013 ◽  
Vol 97 (12) ◽  
pp. 1549-1556 ◽  
Author(s):  
J. R. Viruega ◽  
J. Moral ◽  
L. F. Roca ◽  
N. Navarro ◽  
A. Trapero
Keyword(s):  
Control Strategies ◽  
Exponential Model ◽  
Tree Canopy ◽  
Southern Spain ◽  
Limited Information ◽  
Spore Trap ◽  
Disease Epidemiology ◽  
Inoculum Production ◽  
Pathogen Survival ◽  
Fallen Leaves

Olive scab caused by the mitosporic fungus Spilocaea oleagina is the most important foliar disease of olive. Limited information is available on pathogen survival and disease epidemiology; however, this information is essential for development of new control strategies. Pathogen survival and inoculum production on infected olive leaves and conidial dispersal were evaluated during 4 years in an olive orchard of the susceptible ‘Picual’ in southern Spain. Infected leaves in the tree canopy were important for pathogen survival and conidia production. The number of conidia per square centimeter of scab lesion and their viability varied greatly throughout the seasons and between years; conidial density in lesions was highest (about 1 to 5 × 105 conidia cm–2) from November to February in favorable years. Conidial density declined sharply in other periods of the year (becoming zero in summer) or in less favorable years. The pathogen did not form new conidia in scab lesions, although some pseudothecia-like structures and chlamydospores were detected on fallen leaves. Under humid conditions, the pathogen could not be detected on fallen leaves after 3 months because the leaves were colonized by saprophytic fungi. The dispersal of conidia as a function of distance from infected leaves in the tree canopy was well described by an exponential model which, together with the lack of conidia in a Burkard spore trap, showed that conidia were mainly rain-splash dispersed. Some trapped conidia were attached to olive leaf trichomes, suggesting that detached trichomes might enhance wind dispersal of conidia.

scholarly journals Growth of White Spruce, Picea glauca, Seedlings in Relation to Microenvironmental Conditions in a Forest-Prairie Ecotone of Southwestern Manitoba

2007 ◽  
Vol 121 (2) ◽  
pp. 191 ◽  
Author(s):  
Sophan Chhin ◽  
G. Geoff Wang
Keyword(s):  
Soil Temperature ◽  
Populus Tremuloides ◽  
Picea Glauca ◽  
Carbon Allocation ◽  
White Spruce ◽  
Height Growth ◽  
Tree Canopy ◽  
Morphological Adaptation ◽  
Southern Limit ◽  
Temperature Conditions

The influence of microenvironmental conditions on the growth performance (i.e., diameter and height growth) of White Spruce [Picea glauca (Moench) Voss] seedlings was examined within three contrasting habitats: White Spruce tree islands, open prairies and Trembling Aspen (Populus tremuloides Michx.) groves. These habitats exist within a disjunct occurrence of White Spruce at its southern limit of distribution in three mixed-grass prairie preserves in the Spruce Woods Provincial Park within the forest-prairie ecotone of southwestern Manitoba. Microenvironmental measurements (i.e., light, temperature, relative humidity, soil moisture) were obtained on 10 sites in each of the three habitats and growth characteristics of 60 White Spruce seedlings were measured in each of three habitats. Higher light and soil temperature conditions occurred within the open prairie. In contrast, lower light and soil temperature conditions occurred under the tree canopy of aspen groves and the northern aspect of spruce islands, which moderated the effect of the dry regional climate. Height growth did not vary significantly among the three habitats. The greater diameter growth and decreased slenderness of White Spruce seedlings in the open versus the shaded habitats appears to be a result of increased photosynthesis at higher light intensity and may also represent a morphological adaptation to withstand the effect of increased wind exposure. The increased slenderness of White Spruce in the shaded habitats appears to be a morphological adaptation of increasing carbon allocation towards height growth and thus maximizing effective competition for light.

scholarly journals Hypothesis and Theory: Fungal Spores in Stemflow and Potential Bark Sources

2021 ◽  
Vol 4 ◽  
Author(s):  
Donát Magyar ◽  
John T. Van Stan ◽  
Kandikere R. Sridhar
Keyword(s):  
Species Composition ◽  
Fungal Spores ◽  
Complex Function ◽  
Chemical Properties ◽  
Fungal Species ◽  
Tree Canopy ◽  
Fungal Colonization ◽  
Palm Species ◽  
Conidial Concentration ◽  
Bark Structure

The study of stemflow fungi began over 50 years ago. Past work has been performed in different climatic regions of the world, with different sampling methods, by mycologists focusing on different taxonomical groups. Therefore, we aim to synthesize this work to delineate major conclusions and emerging hypothesis. Here, we present: (1) a systematic compilation of observations on stemflow conidial concentration, flux, and species composition; (2) an evaluation of the methods underlying these observations; (3) a testable theory to understand spatiotemporal dynamics in stemflow (including honeydews) conidial assemblages, with a focus on their relationship to bark structure and microhabitats; and (4) a discussion of major hypotheses based on past observations and new data. This represents a knowledge gap in our understanding of fungal dispersal mechanisms in forests, in a spatially-concentrated hydrologic flux that interacts with habitats throughout the forest microbiome. The literature synthesis and new data represent observations for 228 fungal species’ conidia in stemflow collected from 58 tree species, 6 palm species, and 1 bamboo species. Hypothetical relationships were identified regarding stemflow production and conidial concentration, flux, and species composition. These relationships appear to be driven by bark physico-chemical properties, tree canopy setting, the diversity of in-canopy microenvironments (e.g., tree holes, bark fissures, and epiphytes), and several possible conidia exchange processes (teleomorph aerosols, epi-faunal exchanges, fungal colonization of canopy microhabitats, and droplet impacts, etc.). The review reveals a more complex function of stemflow fungi, having a role in self-cleaning tree surfaces (which play air quality-related ecoservices themselves), and, on the other hand, these fungi may have a role in the protection of the host plant.

Fungal colonization of aspen roots following mechanical site preparation

2003 ◽  
Vol 33 (12) ◽  
pp. 2372-2379 ◽  
Author(s):  
J M Pankuch ◽  
P V Blenis ◽  
V J Lieffers ◽  
K I Mallett
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pathogenic Fungi ◽  
White Spruce ◽  
Site Preparation ◽  
Fungal Colonization ◽  
Preparation Technique ◽  
Mechanical Site Preparation ◽  
Armillaria Ostoyae ◽  
Root Tissues

Fungal colonization of aspen (Populus tremuloides Michx.) roots was examined in boreal mixedwood sites that were mechanically site prepared 8–10 years earlier for white spruce (Picea glauca (Moench) Voss) regeneration using disc trenchers or ripper plows. A survey of root wounds determined that Armillaria sinapina Bérubé & Dessureault and Armillaria ostoyae (Romagn.) Herink were both wound pathogens of aspen; however, A. sinapina was more frequently associated with wounds than was A. ostoyae. Armillaria ostoyae was more common on unwounded root tissues. Sixty percent of wounds infected by A. sinapina were not compartmentalized and the likelihood of an A. sinapina infection did not increase with increasing wound size. Pathogenic fungi other than Armillaria were rarely associated with root wounds. Sever wounds were associated with furrows; scrape wounds were located both along and between furrows irrespective of the site-preparation technique (ripper plow vs. disk trencher).

scholarly journals Recovery from fire affects spatial variability of nutrient availability in boreal aspen ecosystems

2018 ◽  
Author(s):  
Sanatan Das Gupta ◽  
M. Derek MacKenzie
Keyword(s):  
Spatial Variability ◽  
Spatial Patterns ◽  
Populus Tremuloides ◽  
Nutrient Availability ◽  
Fire Ecology ◽  
Chemical Properties ◽  
Tree Canopy ◽  
Soil Microbial ◽  
Nutrient Bioavailability ◽  
Tree Canopy Cover

Fire is a key driver of nutrient biogeochemistry in boreal ecosystems. Although a significant amount of research has been conducted to understand boreal fire ecology, it is still unclear how fire affects the spatial distribution of nutrients and what mechanisms are responsible for the post-fire recovery of spatial patterns. In this study, we examined spatial variability in soil nutrient bioavailability and related aboveground (AG) and belowground (BG) properties in three boreal aspen (Populus tremuloides Michx.) stands in northern Alberta at different stages of post-fire recovery. The studied sites include a 1-year old post fire stand (PF), a 9-year old stand at canopy closure (CC), and a 72-year old mature stand (MA). Ion exchange resin was used to measure nutrient bioavailability in-situ and was related to AG (vegetation and forest floor characteristics) and BG (soil microbial and chemical) properties. Significant spatial patterns were found in all three stands. PF stand had the greatest coarse scale spatial patterns (> 23 m) and availability of major macronutrients (N, P, and K). Shorter spatial range (5 to 10 m) of nutrient availability was observed in the stand with longest time since fire. Soil microbial activity was the strongest driver of nutrient availability in the PF stand, whereas contributions from aboveground variables such as understory vegetation, tree canopy cover, coarse woody debris (CWD), distance to nearest tree, and tree size was observed only in the CC and MA stands. The findings from the current study suggest that post-fire nutrient availability follows spatially predictable patterns, and confirm the hypothesis that stand replacing fire creates uniformity in nutrient availability and that the development of post-fire heterogeneity is a product of increasing ecosystem complexity.

Microscopy studies of powdery mildew on summer squash

1991 ◽  
Vol 49 ◽  
pp. 520-521
Author(s):  
John S. Gardner ◽  
W. M. Hess
Keyword(s):  
Powdery Mildew ◽  
Tip Growth ◽  
Hyphal Growth ◽  
Plant Tissues ◽  
Vegetative Hypha ◽  
Powdery Mildews ◽  
Summer Squash ◽  
Conidial Formation ◽  
Polar Tip Growth ◽  
Short Conidiophore

Powdery mildews are characterized by the appearance of spots or patches of a white to grayish, powdery, mildewy growth on plant tissues, entire leaves or other organs. Ervsiphe cichoracearum, the powdery mildew of cucurbits is among the most serious parasites, and the most common. The conidia are formed similar to the process described for Ervsiphe graminis by Cole and Samson. Theconidial chains mature basipetally from a short, conidiophore mother-cell at the base of the fertile hypha which arises holoblastically from the conidiophore. During early development it probably elongates by polar-tip growth like a vegetative hypha. A septum forms just above the conidiophore apex. Additional septa develop in acropetal succession. However, the conidia of E. cichoracearum are more doliform than condia from E. graminis. The purpose of these investigations was to use scanning electron microscopy (SEM) to demonstrate the nature of hyphal growth and conidial formation of E. cichoracearum on field-grown squash leaves.

Sign in / Sign up

Export Citation Format

Share Document