John Dighton

• Ph. D. London
• Rutgers, The State University of New Jersey

Dead coarse woody debris (fungal food resources) on the forest floor is an ignition source for forest fires. The rate of decomposition of the debris is largely influenced by fungi, determining its residence time on the forest floor. We asked if southern pine bark beetle (Dendroctonus frontalis) attack of pitch pine (Pinus rigida) alters the decompo...

Mercury (Hg) is a toxic heavy metal pollutant that is globally distributed due to atmospheric deposition to non-point source locations. Leaf surfaces directly sequester atmospheric Hg. Little is known of how phylloplane (leaf surface) fungi are influenced by Hg pollution. Through culture-based methodology, this study analysed fungal phylloplane com...

Almost all plants in nature harbor fungi in their roots but the knowledge on distribution and the underlying principles of assemblage is still poorly developed for the root-associated fungi. In this study we analyzed the root endophytic fungal communities associated with switchgrass, rosette grass, and pitch pine in the acidic, oligotrophic pine ba...

This book is an overview of current international research regarding fungal biology. This book includes the following topic areas: 1. INTEGRATING GENOMICS AND METAGENOMICS INTO COMMUNITY ANALYSIS, 2. RECENT ADVANCES IN FUNGAL ENDOPHYTE RESEARCH, 3. FUNGAL COMMUNITIES IN TERRESTRIAL ECOSYSTEMS, 4. FUNGAL COMMUNITIES IN MARINE AND AQUATIC ECOSYSTEMS,...

In all subjects in science new findings and use of new technologies allow us to develop an ever-greater understanding of our world. With the evolution of molecular tools for identifying fungi and genomics to understand relationships between fungal species, the entire concept of fungal taxonomy has been changed from classical Linnean nomenclature to...

Twenty distinct fungal isolates were analysed using three methods of sample preparation for FTIR spectroscopy and FTIR-ATR microspectroscopy to test for differences in surface chemical composition between living and dried fungal samples, as well as differences between surface chemistry and overall chemistry of homogenized dried samples. Results ind...

Background/Question/Methods In arctic regions, lichens are recognized as important components of the food web and biogeochemical cycles, but the lichen role in temperate areas lichen has been overlooked. In the Pinelands of NJ, lichens constitute an important component of the forest; many trees have >60% lichen cover and in some places the biomass...

Soil is a complex milieu of physical and biological entities that regulates the availability of nutrients for plant growth. The interactions between the elements of the soil biota and the plants during this process are complex and often rely on feedbacks between the plants and the great diversity of soil organisms that function to regulate processe...

Our daily life is deeply interwoven with diverse filamentous fungi. These fungi are essential to many ecosystem functions. The estimates of the potential number of fungi predicted to occur on Earth are between 1.5 million and over five million species. We know, however, very little of the biology and ecological functions of most of these fungal spe...

We have combined the use of atomic force microscopy (AFM) and micro-attenuated total reflectance Fourier transform infrared (micro-ATR-FT-IR) imaging to show the extent of exoenzyme influence around individual hyphae of three fungal species growing on cellophane. AFM data show that surface roughness of the cellophane substrate is significantly lowe...

This paper reports the first record of the mycorrhizal status of the state-endangered plant Rhynchospora knieskernii (Knieskern's beaked sedge, formerly KnieskerrTs beaked rush). Root samples of this plant were obtained from two locations in the New Jersey Pine Barrens. Roots from one site had no mycorrhizal colonization, whereas roots from the sec...

Disturbance is an important factor in changing ecological processes. Forested ecosystems undergo natural disturbances of fire and windthrow and disturbances involved in management (thinning, harvesting, control burning). Using the New Jersey pine barrens as model system for eastern US mixed forests, we have observed that under conditions of repeate...

Upland forests of the New Jersey pine barrens are characterized by a pine and oak forest canopy. The herbaceous layer consists primarily of ericaceous shrub species. Scattered throughout the region grass-sedge and lichen–moss dominated patches under a pine canopy can also be found. It is generally believed these patches come about after severe dist...

Metals are toxic to both plants and fungi, and elevated soil metal concentrations have been documented to change the structure of ectomycorrhizal communities. Mercury (Hg) is a highly toxic metal and inhibits the growth of ectomycorrhizal fungi (ECMF) in axenic culture. However, the effects of Hg on the growth of tree seedlings and the development...

We tested the effects of using an inoculum containing natural ericoid roots and soil (NERS) with two fertilizer and irrigation rates on plant growth, shoot (stems and leaves) nutrient concentration, leachate quality, and mycorrhizal colonization of container-grown Coast Leucothoe [Leucothoe axillaris (Lam.) D. Don] and Japanese Pieris [Pieris japon...

Micro-attenuated total reflectance Fourier transform infrared spectroscopy (micro-ATR FTIR) was used to investigate the chemical composition of biodegradable films produced from starch and starch: lignin in a 90:10 ratio. Preparation of the starch and lignin solutions followed that of Vengal & Srikumar [1] in which tensile strength of films was inv...

The distribution and phylogeny of extant protein-encoding genes recovered from geochemically diverse environments can provide insight into the physical and chemical parameters that led to the origin and which constrained the evolution of a functional process. Mercuric reductase (MerA) plays an integral role in mercury (Hg) biogeochemistry by cataly...

Soil nematodes play a crucial role in the terrestrial nitrogen cycle by accelerating the release of ammonium from microorganisms (bacteria and fungi). As aquatic organisms, nematodes are likely to be affected by predicted changes in precipitation patterns and soil moisture during the 21st century. The objective of this study was to measure the resp...

Increases in the frequency of soil drying and extreme precipitation projected by climate models may have important consequences for soil microbial community composition. However, the microbial response may occur over short time scales not captured by traditional sampling methods. Following a 2-year rainfall exclusion experiment in a pine forest eco...

Forests in the New Jersey pine barrens are frequently prescribed burned to reduce fuel loads and risk of wildfire. To acquire baseline data for effects of prescribed burns on ectomycorrhizal diversity and nutrient uptake, field studies were undertaken in two upland pine–oak forests in the New Jersey pine barrens subjected to different burn regimes....

The nutrient status of a Eucalyptusgrandis Hill ex Maiden field fertilizer experiment in Natal, South Africa, was assessed at 6 and 18 months by a bioassay test in which the rate of influx of 15N, 32P, and 86Rb in roots excised from trees was measured. Fertilizer treatments consisted of all combinations of two levels of nitrogen (N), phosphorus (P)...

The presence and quality of the belowground mycorrhizal fungal community could greatly influence plant community structure and host species response. This study tests whether mycorrhizal fungal communities in areas highly impacted by anthropogenic disturbance and urbanization are less species rich or exhibit lower host root colonization rates when...

Projected changes in precipitation patterns in the northeastern U.S. may alter soil moisture dynamics and cause a shift in the structure and function of soil microbial communities. We studied the potential for such changes by manipulating annual precipitation amount in an oak–pine forest of the New Jersey Pinelands. During a two-year field study we...

Heavy metals have been shown to negatively affect the growth of ectomycorrhizal fungi (ECMF). In addition, ECMF have been shown to accumulate heavy metals and to protect host trees from metal toxicity. However, specific literature on the interactions between ECMF and mercury (Hg) is scant. This paper describes the responses of ECMF to Hg in axenic...

Background/Question/Methods An increase in precipitation amount and intensity, which are projected for the northeastern U.S., may lead to changes in the terrestrial nitrogen cycle. We studied the potential for such changes in the Pinelands ecosystem of southern New Jersey. During a two-year field study we measured the response of inorganic nitrog...

Microbial communities play a pivotal role in soil nutrient cycling, which is affected by nitrogen loading on soil fungi and particularly mycorrhizal fungi. In this experiment, we evaluated the effects of allochthonous nitrogen addition on soil bacteria and fungi in two geographically distinct but structurally similar scrub oak forests, one in Flori...

Background/Question/Methods Understanding mechanisms underlying recovery following disturbance are essential for the accurate prediction of carbon and nitrogen dynamics in forest ecosystems. We studied the recovery of carbon (C) and nitrogen (N) cycling following three major disturbances in pine and oak-dominated forests on the Atlantic Coastal Pla...

New Jersey’s nursery growers participated in developing protocols and implementing schemes of using natural mycorrhizae to produce container-grown nursery crops including: ‘Harvest Moon’ Echinacea, ‘Karen Purple’ azalea, ‘Pee Wee’ oakleaf hydrangea, ‘Forever &Ever Double Pink’ bigleaf hydrangea, and ‘Golden Mop’ chamaecyparis. The plants were grown...

Liners of two azalea cultivars Delaware Valley White ‘DVW’ and Silver Sword ‘SS’ were container grown in bark- or peat-based substrate media fertilized with Nutricote at full (FR, Control) and half rate (HR) using commercial and natural mycorrhizal sources for each treatment. They were compared to FR and HR treated plants. Two sets of treated plant...

Low intensity control burns are a standard fuel reduction management tool used in pine barrens ecosystems. Periodic disturbances through fire can be an important influence on the cycling of nutrients within the ecosystem. Previous studies have shown that the inorganic chemistry of leaf litter residues differs with increasing temperature. Our study...

Background/Question/Methods We evaluate the relative importance of trophic control in the soil micro-food web of two geographically distinct but structurally similar scrub oak forests, one in Florida (FL) and one in New Jersey (NJ). We experimentally applied allochthonous nitrogen as 0 Kg Ha-1 Yr-1 (deionized water control), 35 Kg Ha-1 Yr-1 and 7...

Radionuclides in the environment are one of the major concerns to human health and ecotoxicology. The explosion at the Chernobyl nuclear power plant renewed interest in the role played by fungi in mediating radionuclide movement in ecosystems. As a result of these studies, our knowledge of the importance of fungi, especially in their mycorrhizal ha...

This work builds on an earlier culture study where we determined that species diversity of competing saprotrophic phyllpolane fungi had only a negligible effect on the establishment and coexistence of a target fungus, Pestalotia vaccinii. Here, we explore preliminary evidence suggesting that spore density is a more important contributing factor to...

Following the development of nuclear weapons and the subsequent evolution of nuclear energy-generating industries, there has been considerable concern regarding the safe storage of radionuclide waste. Widescale release, in the aftermath of nuclear detonations or as the result of malfunction of atomic energy plants and reprocessing facilities, has a...

The accident at the Chernobyl Atomic Energy Station resulted in radiation contamination of large tracts of land and particularly the reactor building itself. Sustained exposure of microfungi to radiation appears to have resulted in formerly unknown adaptive features, such as directed growth of fungi to sources of ionizing radiation. We evaluate her...

The accident at the Chernobyl Atomic Energy Station resulted in radiation contamination of large tracts of land and particularly the reactor building itself. Sustained exposure of microfungi to radiation appears to have resulted in formerly unknown adaptive features, such as directed growth of fungi to sources of ionizing radiation. We evaluate her...

Temperature dependant mineralization dynamics during fire of litter species characteristic of the New Jersey pine barrens was determined. Senescent leaf material of pitch pine (Pinus rigida), white oak (Quercus alba) and black huckleberry (Gaylusssacia baccata) were collected at the time of abscission; sorted, ground and oven-dried at 70 °C. Replic...

The addition of leaf litter to soil influences both the nutrients and polyphenols of soil. It is likely that contrasting nutrient and polyphenolic composition of different plant litters may affect plant growth, mycorrhizal and soil arthropod communities. We report results from a microcosm experiment of effects of incorporation of three single leaf...

We examined the influence of phosphorus source and availability on host plant (Pinus rigida) response to ectomycorrhizal diversity under contrasting P conditions. An ectomycorrhizal richness gradient was established with equimolar P supplied as either inorganic phosphate or organic inositol hexaphosphate. We measured growth and N and P uptake of in...

We investigated the influence of three concentrations of water extracts of three leaf litter species (pitch pine, huckleberry and white oak) and a mixture of all litters on the germination of pitch pine seeds and initial seedling growth in a microcosm experiment. All three plant species are important components of the pine barrens ecosystems in New...

A gradient of increasing N deposition was identified in a southwestern to northeastern transect through the New Jersey pine barrens. The effect of this change in N deposition rate on soil chemistry and ectomycorrhizal morphotype community of pitch pine was studied by sampling from the field under mature pine trees, by planting bait seedlings into t...

During the last 15 years, about 2000 strains of 200 species of 98 genera of fungi have been isolated from around the Chernobyl Atomic Energy Station. Many of these microfungi are capable of growing into and decomposing 'hot particles'; carbon based radioactive graphite from the reactor and there are suggestions that some fungi actively direct their...

The fatty acid composition of 16 different soil fungi (ascomycetes, basidiomycetes, mitosporic fungi) and a fungal-feeding nematode Aphelenchoides sp. reared on seven fungal species was investigated. Additionally, fatty acid profiles of Aphelenchoides sp. and A. saprophilus grown on the same fungal food source,Agrocybe gibberosa, were compared. Thi...

Young pitch pine seedlings are frequently subjected to prescribed burns in the New Jersey pine barrens as part of the management to eliminate fuel load in these forests, thereby reducing the risk of wildfire. The burns are relatively cool and release nutrients without killing the vegetation. Not all nutrients mineralized are immediately available t...

We compared soil N and P availability in similar oak forest stands located in either an urban or a rural area. To compare N and P availability in the urban and rural soils, we measured: (1) net N-mineralization potential and extractable inorganic P; (2) plant demand for NH4+, NO3− and PO43− using a root nutrient uptake bioassay; and (3) N and P acq...

Summary • The influence of ectomycorrhizal fungal diversity on plant performance was investigated by establishing a gradient of ectomycorrhizal diversity on Betula populifolia (grey birch) seedlings. • We measured growth, as well as N and P uptake, of individual B. populifolia seedlings inoculated with replicate one, two and four species ‘communiti...

Studies of chemical changes in leaf litter resources during decomposition have relied upon bulk litter analysis using wet chemistry. We introduce, here, the use of microscopic Fourier transform infrared spectroscopy (FT–IR) to evaluate changes in the carbohydrate chemistry of leaf litters at the scale of resolution relevant to the study of microbes...

The growth of Aphelenchoides sp. populations was investigated in vitro with 17 different fungal species as food source. Nematode mass cultures were obtained with saprophytic (Agrocybe, Chaetomium) and especially with mycorrhizal fungi (Cenococcum, Hymenoscyphus, Laccaria). Mitosporic species, like Alternaria, Monocillium or Penicillium, were genera...

Leaf litter decomposition is largely effected by the enzymatic action of fungal colonizers of leaf material. Microscopic attenuated total reflectance (ATR) infrared spectroscopy would be a useful tool to evaluate changes in leaf litter carbohydrate chemistry over time during the colonization process at the scale of resolution of the fungal hyphae....

The influence of litter quality on root growth, ectomycorrhizal communities and decay processes was investigated through a litter bag experiment. Litter bags containing either pine needles, oak leaves or oak+pine mix were placed within the O horizon of a lowland pitch pine (Pinus rigida) forest in the New Jersey Pinelands. Upon retrieval, ingrown p...

We compared the ectomycorrhizal community structure of oak forest stands located in either an urban or a rural area. Urban stands had higher N deposition rates, soil heavy metal levels, and earthworm counts than rural stands. Ectomycorrhizal types were quantified on roots of mature oak (Quercus) in soil cores and on Quercus rubra L. seedlings grown...

Dwarf shrub heaths are common vegetation types of the Arctic and Subarctic. Some of the dominant plants in these communities release toxic substances which can affect neighbouring plants. We investigated the effects of leaf extracts from two dwarf shrubs, Cassiope tetragona and Empetrum hermaphroditum, and from mountain birch, Betula pubescens spp....

Any study of the fate of genetically modified microorganisms (GMMs), released into the environment, must examine how far they can disperse from their release site. The likelihood of dispersal will depend on two key factors: 1.1. . Speed and distance of dispersal.2.2. . Survival and/or reproduction, enabling them to reach new environments or hosts i...

Upper soil horizons are important natural resources for the growth of plants for food and industry (crops, animal produce, timber and biofuels). The maintenance of soil fertility, with minimal exogenous inputs, is vital for long-term sustainable plant productivity with viable economic returns

1. We have developed a cellular automaton model based on the measured and inferred properties of the fungal saprophytes, Mucor hiemalis, Agrocybe gibberosa, Chaetomium globosum and Sphaerobolus stellatus. In this model, the fungal mycelia are represented by the players MH, AG, CG and SS, respectively. The model was used to investigate the rate of b...

Despite an upsurge in national and international debate on environmental issues since the Earth Summit in Rio de Janeiro in 1992, fungi, vital to the functioning of terrestrial and aquatic ecosystems, are rarely mentioned. This volume helps redress this imbalance by considering fungi in the context of the impact of humankind's activity on their hab...

The effect of passage through the earthworm gut on the viability of spores of saprotrophic fungi was found to vary depending on fungal and earthworm species. Of 5 fungal species fed to Lumbricus terrestris L., the spores of two (Fusarium lateritium Nees, and Agrocybe temulenta (Fries)) failed to germinate after gut passage, while germination of Tri...

The belowground biota (nematodes, fungal biomass, roots and mycorrhizal development) of a mature Sitka spruce stand under the influence of acid precipitation (equimolar sulphuric acid and ammonium nitrate) was investigated. Sampling took place after 3 years of treatment and 5 months after the end of treatment. Acidification led to a decrease of the...

In laboratory experiments survival, feeding and reproduction of nematodes in cultures with mycorrhizal and saprophytic fungi were investigated. Nematodes extracted from the organic layer of a spruce forest soil were inoculated to fungal plates. The fungal feeder Aphelenchoides saprophilus was the most successful species to multiply. With mycorrhiza...

Previous research has shown that plant extracts, e.g. from boreal dwarf shrubs and trees, can cause reduced growth of neighbouring plants: an effect known as allelopathy. To examine whether arctic and subarctic plants could also be affected by leaching of phytochemicals, we added extracts from the commonly occurring arctic dwarf shrubs Cassiope tet...

Comparisons are made between nutrient cycling systems of arctic tundra, temperate forest, tropical forest, grassland, arable, and desert ecosystems. Detailed nutrient budgets are not given, but general differences between ecosystems are discussed primarily in relation to the role of soil fungi. General discussion reviews the impact of anthropogenic...

New questions are being asked about the functional role of soil fungi, plant roots and their interactions. Existing methods to study the species composition and biomass of soil fungi and roots are outlined and the limitations of the data derived from them are discussed. The integration of these existing methods and new technologies in multi-discipl...

The nutritional requirements of Eucalyptus grandis Hill ex Maiden seedlings were studied in glasshouse pot experiments. Nitrogen (N), phosphorus (P), and potassium (K) demand was assessed by bioassays, in which the uptake of tracers (N-15, P-32, or Rb-86) by roots excised from the seedlings grown at different levels of nutrient supply was measured....

Bioassays have been developed which can provide diagnostics of the nutritional status of trees. They measure the flux of N, P or Rb for K into roots from standard solutions where the rate of influx is inversely related to nutrient supply. The bioassays have been applied in the study of nutrient deficiencies in Eucalyptus grandis in both pot and fie...

Using a root bioassay, a peak of phosphorus demand of a developing series of Sitka spruce (Picea sitchensis (Bong.) Carr) plantations, growing on a peaty-gley soil in upland Great Britain, has been shown to occur at canopy closure. Demonstration of the increased demand by the forest at this stage of development agrees well with theoretical consider...

13.1 Introduction Although, in agriculture, soil fertility is primarily main-tained by frequent fertilizer applications, this is not usually the case with forestry. The nutrients required by forest trees are normally provided by nutrient cycl-ing, which is 1he circulation of nutrients in the forest ecosystem. It is only where this supply is serious...

S ummary Roots were examined from three‐year‐old Scots pine seedlings (Pinus sylvestris L.) growing on a humo‐ferric podzol in monolith soil lysimeters which had received simulated acid rain at pH 3 or non‐acidified rain. This is about 30 times the rate of wet H ⁺ deposition at the site from which the lysimeters were taken. Root biomass was similar...

Ecosystem research is in its infancy, its roots are varied, it has a reasonable theoretical basis but it lacks the extensive data so essential for the development of the subject. The very complexity and scale of ecosystems makes analysis and comprehension difficult. However, the stimulus for research lies in the recognition that the ecosystem is a...

Sheathing mycorrhizal fungi have been shown to possess phosphatase enzymes which can hydrolyse inositol hexaphosphate. In a range of mycorrhizal fungi, this activity was often greater than in two common decomposer basidiomycetes. Mycorrhizal birch and pine roots both produce phosphatases. In birch production is inversely related to the inorganic ph...