A dry soil is generally a hard soil. Thus, the effects of water stress and mechanical impedance on plant growth are difficult to separate. To achieve this we have developed a growth cell that allows manipulation of the strength of growth media (i.e. mechanical impedance) without altering the availability of water or nutrients. We monitored leaf elongation rates of barley and wheat seedlings before and after the mechanical impedance to root growth was increased. Results show that a large and rapid reduction (within 10 min) of leaf elongation rates occurred after impedance to the roots was increased. The average reductions for barley and wheat, with associated standard errors, were 22·6% (4·84) and 36·2% (5·48), respectively. The data are consistent with the hypothesis that mechanical impedance of roots might have a direct negative effect on leaf growth even where nutrients and water are in plentiful supply to the plant. The implications of the rate of the response are examined with respect to the underlying mechanisms controlling root–shoot signalling.

Sunflower seedlings (Helianthus annuus hybrid Select) were grown in a complete nutrient solution in the absence or presence of Cd2+ (10 and 20 μM). Analyses were performed to establish whether there was a differential effect of Cd2+ on mature and young leaves. After 7 d the growth parameters as well as the leaf area had decreased in both mature and young leaves. Accumulation of Cd2+ in the roots exceeded that in the shoots. Seedlings treated with Cd2+ exhibited reduced contents of chlorophyll and CO2 assimilation rate, with a greater decrease in young leaves. The photochemical efficiency of photosystem II (PSII) was not altered by Cd2+ treatment in either mature or young leaves, although during steady-state photosynthesis in young leaves there was a significant alteration in the following parameters: quantum yield of electron transport by PSII (ΦPSII), photochemical quenching (qP), non-photochemical quenching (qNP), and excitation capture efficiency of PSII (Φexc).

A cDNA coding for a fungal amino acid transporter (AmAAP1) was identified from Amanita muscaria ectomycorrhizas. The transporter gene was expressed at a basal level under all conditions investigated, but its expression was enhanced 10-fold in the absence of a N source utilized by the fungus. Nitrate was not a suitable N source for A. muscaria and resulted in maximal AmAAP1 expression. The expression of AmAAP1 in a yeast mutant revealed its function as a high-affinity amino acid transporter with a broad substrate spectrum. AmAAP1 takes up all investigated amino acids with Km values between 22 μM for histidine and up to 100 μM for proline. Gene expression and amino acid uptake data together indicate two main functions for AmAAP1: uptake of amino acids from soil for fungal nutrition, and prevention of an amino acid loss by hyphal leakage in the absence of a suitable N source.

Living epidermal cells of cowpea (Vigna unguiculata (L.) Walp.) were examined by contrast-enhanced video microscopy during penetration by invasion hyphae of the monokaryotic stage of the cowpea rust fungus (Uromyces vignae Barclay race 1). In resistant or susceptible host cvs, the plant nucleus migrated to the penetration site before the fungus had fully penetrated the plant wall and, at sites of unsuccessful infection, remained during the formation of a callose-containing papilla. Nuclear migration was also induced by applying hemicellulase, but not H2O2, to localized sites of wall damage. Hemicellulase-induced migration was inhibited by calcium chelators and a protein kinase inhibitor, but not catalase. In both resistant and susceptible cvs, the plant nucleus migrated away from successful infection sites at about the time that the fungal penetration peg made contact with the plant plasma membrane, and the epidermal cell showed no further cytological responses to the growth of the fungal intra-epidermal vesicle. In the susceptible cv., the nucleus migrated back to the fungus when the latter initiated tip growth. Inhibitors of transcription or translation did not affect this migration and only slightly reduced fungal growth. In the resistant cv. in which the invaded cell exhibited a hypersensitive response (HR), the plant nucleus changed its appearance before the cessation of cytoplasmic streaming and usually did not migrate to the fungus, even if the latter initiated tip growth. Nuclear DNA cleavage usually followed the subsequent cessation of cytoplasmic streaming. Treatments that delayed cell death and increased fungal growth also increased the frequency of nuclear migration to the fungus. It is argued that these and other data suggest that U. vignae negates nonspecific, penetration-induced, defence responses upon entering cells of both susceptible and resistant cultivars. The results also suggest that effects on the plant nucleus are one of the earliest signs of the HR in this system, often preceding the cessation of cytoplasmic streaming and detectable changes in plasma membrane permeability.

To study the relationship between copper sensitivity and membrane permeability in Arabidopsis, the seedling growth rates (measured as root extension and f. wt increase) of 10 ecotypes with differing copper sensitivities were compared with their patterns of potassium efflux and copper uptake. At 36 h, inhibition of root extension in 40 μM Cu correlated well with K+ efflux (r=0·96) and a decrease in osmolality (r=0·96). By contrast, neither tissue osmolality nor K+ efflux correlated significantly with growth inhibition after 4 h Cu treatment. In detailed time-course studies of two of the less sensitive ecotypes (Shadhara and Ws) and two of the more sensitive ecotypes (Berkeley and Limeport) in 20 μM Cu, growth, K+ retention and osmolality decreased rapidly during the first 4 h. Only the two less sensitive ecotypes recovered during the following 32 h. A similar pattern was observed with 40 μM Cu, except that growth inhibition was more marked. Interestingly, after 4 h the less sensitive ecotypes exhibited greater inhibition than the more sensitive. In time-course measurements, the Cu contents of the four ecotypes were not significantly different when normalised on a f. wt basis. We conclude that variations in the metal sensitivities of Arabidopsis ecotypes are not due to constitutive differences in membrane permeability but, rather, to differences in the ability to reverse K+ efflux. The possibility that short-term Cu-induced K+-leakage is regulated by channels rather than lipid oxidation is discussed.

Some mycorrhizal plants exhibit greater resistance than nonmycorrhizal plants to aluminium toxicity. This has not yet been shown for banana despite its importance as a cash and food crop in tropical regions, although bananas are sensitive to aluminium stress. We studied the effects of the arbuscular mycorrhizal fungus Glomus intraradices in alleviating aluminium toxicity in the banana cultivar Grande Naine grown in a continuous-nutrient-flow cultivation system using dilute solution. The micropropagated plants, some of which were inoculated with arbuscular mycorrhizal fungus, were grown for 40 d in pots filled with sand, and continuously irrigated with a nutrient solution containing up to 180 μM of aluminium. Water and nutrient uptake were measured once a week for 24 h, and root arbuscular mycorrhizal fungal colonization, biomass production, and mineral content of roots and shoots were measured at harvest. The root arbuscular mycorrhizal fungal colonization was large, and not significantly influenced by aluminium treatment. The effects of aluminium on both mycorrhizal and nonmycorrhizal plants were: decrease in biomass production, water and nutrient uptake, and magnesium content of roots and shoots; greater aluminium content in roots than in shoots; and increase in potassium and phosphorus content, particularly in roots. A significant positive effect of arbuscular mycorrhizal fungi on plant growth was observed with aluminium treatment, and was most pronounced at the highest concentration. The benefits, compared with nonmycorrhizal plants, included: increase in shoot dry weight, uptake of water and of most nutrients, and in calcium, magnesium and phosphorus content, particularly in roots; decrease in aluminium content in root and shoot; and delay in the appearance of aluminium-induced leaf symptoms. These results indicate that arbuscular mycorrhizal fungi could be effective in alleviating aluminium toxicity to banana plants.

Calluna vulgaris L. (Hull) is not one of the usual hosts of the winter moth, Operophtera brumata L., but outbreaks have caused extensive damage to heather moorland in Scotland in recent years. This study investigated the potential role of environmental change in such outbreaks by rearing O. brumata larvae on C. vulgaris plants grown in open-top chambers for 20 months with enriched CO2 (600 ppm) and nitrogen supply (average 52·5 kg N ha−1 yr−1) in factorial combination. This prolonged exposure to elevated CO2 caused no change in shoot growth, photosynthesis or foliar C[ratio ]N ratio of C. vulgaris, even with increased N supply, indicating that the absence of response was not due to N limitation. Increased N supply itself resulted in increased shoot growth and a decrease in tissue C[ratio ]N ratio. Phenolic content did not change in response to either CO2 or N enrichment, contrary to the predictions of the carbon/nutrient balance hypothesis. In line with the absence of plant response, there was no effect of CO2 on the development of Operophtera brumata on C. vulgaris, and so continued increase in atmospheric CO2 concentration is unlikely to affect directly O. brumata outbreaks on heather moorland. Operophtera brumata showed increased larval development, growth rate and pupal weight on N-treated plants, correlated both to the decrease in foliar C[ratio ]N ratio, and to the increase in shoot extension which was predictive of survivorship. Thus, increased atmospheric N deposition, or increased rates of mineralization in a warmer environment, might increase the severity of O. brumata outbreaks on C. vulgaris. Since the combination of high N availability and disturbance of heather canopy by herbivory is known to result in increased dominance of grasses, it is suggested that this could lead to further degradation of moorland in upland Britain.

Topology is an important component of the architecture of whole root systems. Unfortunately, most commonly applied indices used for characterizing topology are poorly correlated with one another and thus reflect different aspects of topology. In order to understand better how different methods of characterizing topology vary, this paper presents an exploration of several different methods for assigning order within branched root systems on the basis of (a) developmental (centrifugal) vs. functional (centripetal) ordering sequences and (b) whether orders are assigned to individual links or groups of adjacent links (segments). For each ordering system, patterns of scaling in relation to various aspects of link and segment size are explored using regression analyses. Segment-based ordering systems resulted in better fits for simple scaling relationships with size, but these patterns varied between developmental vs. functional ordering as well as the different size metrics examined. The functional (centripetal), link-based ordering system showed complex, non-linear scaling in relation to numbers of links per order. Using a simple simulation model of root growth, it is demonstrated that this method of characterizing root topology in relation to root size might be a more powerful tool for characterizing root system architecture than in the use of simple, single-index characterizations of topology.

Arabidopsis thaliana (L.) Heynh. was exposed to various concentrations of SO2 during almost the entire life cycle. No negative effects of SO2 on shoot biomass production were observed. There was a linear relation between the deposition of SO2 and the atmospheric SO2 concentration. Sulphur accumulated substantially in the shoots upon SO2 exposure. SO2 was either oxidized to sulphate or converted into extra organic sulphur compounds in a sulphate to organic sulphur ratio of 3[ratio ]1, independently of the atmospheric SO2 concentration. Exposure to SO2 resulted in an increase in water soluble non-protein sulphydryl content and a slight increase in the amount of glucosinolates, but both of these play a minor role as sinks for the excess sulphur. The ratio of total nitrogen to total sulphur decreased upon SO2 exposure as a result of the increased sulphate content. The organic nitrogen to organic sulphur ratio did not change upon SO2 exposure, indicating no changes in the composition of sulphur-containing compounds.

Polyamines (PAs) and the cell wall have important roles in plant morphogenesis. An interaction between cell wall components (pectic substances) and polyamines is known and inhibition of polyamine biosynthesis induces inhibition of some morphogenic processes. This is the case of rhizogenesis in tobacco (Nicotiana tabacum L.) thin layers. This paper investigates whether inhibition of polyamine biosynthesis induces modifications in the structure, shape and size of the primary cell walls in tobacco thin layers cultured on a rhizogenic medium, and whether polyamines (putrescine and spermidine) administered in combination with their corresponding inhibitors DL-α-difluoromethylornithine +DL-α-difluoromethylarginine (DFMO+DFMA), cyclohexylamine (CHA), methylglyoxal-bis(guanylhydrazone) (MGBG) restore cell wall characteristics. In treatments with polyamine inhibitors, cell hypertrophy occurred in the lowermost layer of the explant in contact with the medium. Many unusual features were observed in the walls of the hypertrophic cells: an amorphous structure, loosening of the fibrillar component; detachment between contiguous cells, lysis of wall components and an uneven thickness often giving a wavy appearance (in transverse walls). The inhibitors reduced cell wall thickness, and caused a weak positive PATAg reaction for polysaccharides. Polyamines restored cell wall thickness and, in general, the other wall features. Our results show that polyamines are necessary for maintaining cell wall characteristics by strengthening the links between cell-wall components.

In Lake Zürich, populations of the cyanobacterium Planktothrix rubescens develop in the metalimnion during the summer and become gradually entrained in the deepening surface mixed layer during the autumn. It had previously been demonstrated that the daily integrals of photosynthetic production accounted for the growth observed in the metalimnion and greatly exceeded the smaller increase during the autumn. We have now determined the relationship between growth rate (μ) and irradiance (I) in cultures of P. rubescens strain Pla 9316 maintained at 20 °C on a 12[ratio ]12 h light[ratio ]dark cycle: the highest net growth rate averaged over the 24 h (μh) was 0.123 d−1, the dark rate (μD) was −0.020 d−1, the gross rate (ϕm = μh−μD) was 0.144 d−1, the affinity coefficient (α) was 0.0273 (d μmol m−2 s−1)−1 and the compensation point (IC) was 1.76 μmol m−2 s−1. Using the corresponding coefficients calculated for the light period (μLh = 0.267 d−1, ϕLm = 0.287 d−1 and αL = 0.0547 (d μmol m−2 s−1)−1), instantaneous growth rates could be calculated from the irradiance. Comparison with growth rates at 10 °C indicated a Q10 of 1.48. These coefficients were used in a modification of the Smith equation to calculate potential growth rates of Planktothrix from the irradiance and temperature at each time and depth in Lake Zürich. Data on irradiance, vertical light attenuation and temperature were used to calculate the daily integrals of biomass increase over a period of 136 d. These growth integrals gave a closer correspondence to the observed population increase than the photosynthetic integrals calculated previously from measurements made with lakewater samples dominated by Planktothrix. Photosynthetic measurements made with the Planktothrix culture indicated a maximum rate of carbon increase (0.467 d−1 that exceeds the maximum growth rate, which suggests that other factors limit growth over long periods.

The global cycles of carbon and nitrogen are being perturbed by human activities that increase the transfer from large pools of non-reactive forms of the elements to reactive forms that are essential to the functioning of the terrestrial biosphere. The cycles are closely linked at all scales, and global change analyses must consider C and N cycles together. The increasing amount of N originating from fossil fuel combustion and deposited to terrestrial ecosystems as nitrogen oxides could increase the capacity of ecosystems to sequester C, thereby removing some of the excess carbon dioxide from the atmosphere and slowing the development of greenhouse warming. Several global and ecosystem models have calculated the amount of C sequestration that can be attributed to N deposition, based on assumptions about the allocation of N among ecosystem components with different C[ratio ]N ratios. They support the premise that, since industrialization began, N deposition has been responsible for an increasing terrestrial C sink, but there is great uncertainty whether ecosystems will continue to retain exogenous N. Whether terrestrial ecosystems continue to sequester additional C will depend in part on their response to increasing concentrations of atmospheric carbon dioxide, widely thought to be constrained by limited N availability. Ecosystem models generally support the conclusion that responses to increasing concentrations of carbon dioxide will be greater, and the range of possible responses will be wider, in ecosystems where increased N inputs originate as atmospheric deposition. The interactions between N deposition and increasing carbon dioxide concentrations could be altered considerably, however, by additional factors, including N saturation of ecosystems, changes in community composition, and climate change. Nitrogen deposition is also linked to global change issues through the volatile losses of nitrous oxide, which is a potent greenhouse gas, and the role of nitrogen oxides in the production of tropospheric ozone, which could interact with plant responses to elevated carbon dioxide. Any consideration of the role of N deposition in global change issues must also balance the projected responses against the serious detrimental impact of excess N on the environment.

Summary 257

I. DEFINING AND QUANTIFYING OCEANICITY 257

II. ECOLOGICAL CONSEQUENCES OF OCEANICITY 261

III. ECOLOGICAL HISTORY OF OCEANICITY IN WESTERN EUROPE 263

IV. POSITIVE AND NEGATIVE INFLUENCES OF OCEANICITY 267

1. Species versus communities 267

2. Case study – Primula scotica – climatic effects on reproduction 268

3. Case study – cranberry production and anoxia tolerance 268

V. MODIFYING EFFECTS OF OCEANICITY ON PLANT DISTRIBUTION 269

VI. PHYSIOLOGICAL IMPACT OF WARM WINTERS 271

1. Phenology 271

2. Metabolic consequences of warm winters 272

3. Warm winters and mountain-top vegetation 274

VII. TREELINES AND OCEANICITY 276

VIII. CONCLUSIONS 278

Acknowledgements 279

References 279

A cyclic behaviour in the intensity of maritime conditions which varies with the periodic behaviour of the North Atlantic oscillation has recently become apparent in the climatic record of northern Europe. Periodic increases in oceanicity are usually viewed as having a positive effect on plant survival, as milder winters, reduction of temperature extremes, low risk of exposure to frost, and freedom from drought reduce many aspects of environmental stress. However, warmer winters in maritime environments may also have a powerful influence in creating habitats that are unfavourable for many species. The dangers of long periods of soil saturation for overwintering plants, soaking injury to germinating seeds, premature bud burst in spring, depression of treelines by increased cloud cover and high lapse rates, as well as the constant leaching of soils, are all negative aspects of the maritime environment. Woody species in which root dormancy is delayed by mild winters are particularly vulnerable to the consequences of winter flooding. Subsequent re-exposure to oxygen as water tables fall in spring can aggravate flooding damage through post-anoxic injury, leading to severe dieback of anchoring roots. Soil leaching, particularly after human disturbance, can induce nutrient deficiencies and the establishment of oligotrophic communities with reduced productivity. Podzolization and iron pan formation have in the past facilitated the processes of paludification in oceanic regions. The resulting spread of bogs and acid moorlands can further reduce the potential for productivity in both agriculture and natural plant communities. Given the probability that current climatic trends may increase the degree of oceanicity in western and northern regions of Europe, the potentially negative consequences of such a climatic change need to be considered in relation to future ecological changes and their consequences for conservation and land use.

Sarcodes sanguinea and Pterospora andromedea (Ericaceae, Monotropoideae) are nonphotosynthetic myco-heterotrophic plants. Recent studies have shown that the roots of the adult plants are always associated with closely related but exclusive sets of Rhizopogon species (Basidiomycota, Boletales) from section Amylopogon. We have isolated Rhizopogon species that were associated with the adult plants and used them to germinate seeds under gnotobiotic conditions. All Rhizopogon species isolated from either plant species were capable of stimulating seed germination in both Sarcodes and Pterospora. Under the primary conditions used, germination varied from 9 to 73% in the case of Sarcodes and 0 to 13% in that of Pterospora. The single Rhizopogon strain that failed to elicit germination in Pterospora under these conditions did stimulate germination under slightly different conditions. By contrast, seeds failed to germinate on all media which lacked these Rhizopogon species, or in the presence of six other genera of basidiomycetes. Seed germination could be stimulated either through cellophane or at the edge of fungal colonies without direct fungus–seed contact. These results suggest that a diffusible or volatile compound that is unique to Rhizopogon stimulates germination of these plant seeds. Seed lots of Sarcodes from two successive years had similar germination levels. Sarcodes seeds that had overwintered under natural conditions were also stimulated to germinate. These results demonstrate the potential for long-term dormancy. We suggest that a combination of dormancy and the use of specific germination cues might increase the opportunities of these plants for recruitment. In addition, the specific germination response explains at least a part of the specialized associations observed in the adult plants. Nevertheless, the seeds respond to a slightly broader range of Rhizopogon species than has been observed to be associated with the adult plants; thus other factors must also be involved with specificity under natural conditions.

Two families of Helianthus lines, T− (low desiccation rate) and T+ (low desiccation rate), with contrasting osmotic adjustment (OA), obtained from a divergent selection programme, were compared for several morphological traits, ecophysiological parameters and molecular markers. The physiological analysis in a glasshouse experiment showed that the two families were identical in irrigated conditions except for a single trait, relative water loss (RWL: water loss rate of excised leaves). RWL could be used for these genotypes as a physiological marker of OA. A molecular analysis of the two contrasting lines, using differential screening of cDNA libraries, led to the isolation of three specific cDNAs, one of which, DRS26, showed high sequence homology with a mammalian amino-acid transporter. Subsequent RFLP and STS studies, using DRS26 and RAPD bulked analysis, enabled the identification of putative molecular markers of RWL and OA in T−[ratio ]T+ sunflower.

Safflower (Carthamus tinctorius L. cv. S555) and spring wheat (Triticum aestivum L. cv. Anza) were grown with or without the arbuscular mycorrhizal fungus Glomus etunicatum Becker & Gerd., under environmentally controlled conditions. Soil phosphate concentrations were adjusted before planting to produce mycorrhizal (M) and non-mycorrhizal (NM) plants that had similar leaf areas and root length densities at the same stage of development before initiating drought stress treatments. Drought did not affect the amount of mycorrhizal infection in safflower or wheat. Interactions between water stress treatments and mycorrhizal infection on plant growth and phosphorus uptake were limited and only occurred in wheat. NM wheat plants had 28% greater shoot d. wt, slightly greater root length densities, and 39% greater P acquisition than M plants when grown under well watered conditions, but under droughted conditions plant size and tissue P contents of M and NM wheat plants were similar. Mycorrhizas did not affect stomatal behaviour during drought stress in either safflower or wheat, i.e., transpiration and stomatal conductance declined independently of infection as soil water was depleted and leaf water potentials declined. Therefore, mycorrhizal infection did not alter the intrinsic hydraulic properties of the plant/soil system. Whilst wheat maintained turgor of recently expanded leaves during severe drought and safflower did not, mycorrhizal infection had no effect on leaf turgor during drought in either plant species.

Fourier Transform laser Raman spectroscopy was used to generate diagnostic spectra for pigments and biodegradative calcium oxalate in situ in two yellow-pigmented species of the lichen genus Acarospora from contrasting sites in the Antarctic and the Mediterranean. This non-intrusive technique was used to identify the photoprotective pigments rhizocarpic acid and β-carotene by their unique Raman spectral fingerprints. The use of low energy near-IR excitation at 1064 nm eliminated interference from autofluorescence of photosynthetic pigments. The insensitivity of the technique to water permitted the use of field-fresh material. The dominant yellow pigment, rhizocarpic acid, gave a diagnostic pattern of corroborative bands at wavenumbers (ν) 1596, 1665, 1620 and 1000 cm−1. It was possible to discriminate between hydration states of calcium oxalate; the monohydrate (whewellite) featured a ν(CO) stretching band at 1493 cm−1 whereas the dihydrate (weddellite) had a contrasting ν(CO) stretching band at 1476 cm−1. Fourier Transform deconvolution and intensity measurements were used to obtain relative quantitative data for rhizocarpic acid by using its ν(CO) and ν(CONH) amide modes, for carotenoid pigment by its ν(C = C) band at 1520 cm−1 and for calcium oxalates by their ν(CO) bands. ν(CO), ν(CONH) and ν(C = C) are the vibrational stretching modes of the carbonyl C = O, protein amide 1 and alkenyl C = C moieties, respectively, in the pigments and metabolic products of the Acarospora lichens. The ability to determine the precise (20 μm spot diameter) spatial distribution of these key functional molecules in field-fresh thallus profiles and variegations has great potential for understanding the survival strategies of lichens, which receive high insolation, including elevated levels of UV-B, under extremes of desiccation and temperature in hot and cold desert habitats.

Summary 221

I. Introduction 221

1. The role of sucrose in plants 221

2. C4photosynthesis 222

II. Pathway of sucrose synthesis in C4plants 223

III. Control of sucrose synthesis in C4plants 225

1. The diurnal cycle in C3plants 225

2. The diurnal cycle in C4plants 227

3. Abiotic stress and sucrose synthesis 230

4. Integration of sucrose synthesis with other metabolic pathways 232

IV. Future prospects 233

Acknowledgements 234

References 234

Sucrose has a central role in the metabolism of all higher plants. Here we discuss the location of sucrose synthesis in the leaves of C4 plants, the control of flux through the pathway and its response to environmental conditions, and finally some of the prospects for the genetic manipulation of sucrose metabolism in C4 plants. Much of our knowledge about sucrose synthesis in plants comes from C3 species; it is evident, from those studies of C4 species that are available, that there are many similarities between sucrose synthesis in C3 and C4 plants. However, some of the basic regulatory mechanisms common to both C3 and C4 plants seem to have been adapted for the specialized photosynthetic metabolism of C4 plants. There are also some other important differences: for example, some C4 species possess photosynthetic cells with little or no capacity for sucrose synthesis. For these reasons it is not always appropriate to extrapolate directly from C3 to C4 plants. Even where data are available from one C4 species, usually maize, it should not be assumed that all C4 plants are necessarily the same in every respect. Although C4 plants constitute a small fraction of the plant kingdom as a whole, they include a disproportionate number of agriculturally important species. C4 plants also have some advantages over C3 plants for studies of the regulation of cell-specific gene expression and the control of metabolism. For these reasons we suggest that they are worthy of more attention by researchers.

This study investigated the relationships between ericoid mycorrhizal endophytes of the Ericaceae (Northern Hemisphere) and the Epacridaceae (Australia). Over 200 fungi were isolated from the roots of two species of Epacridaceae from Victoria, Australia. The isolates were divided into 12 groups by morphology on quarter-strength potato dextrose agar. All were slow-growing and most were dematiaceous, but groups varied from white through pink to dark olive. The ITS1–5.8S–ITS2 ribosomal DNA was amplified and sequenced from eight isolates, forming typical ericoid mycorrhizal morphology in Epacris impressa and one nonmycorrhizal isolate. Sequences were compared, by using similarities and maximum-parsimony analysis, with those of Hymenoscyphus ericae (Leotiales) and Oidiodendron species (Hyphomycetes), the most common endophytes of the Ericaceae. Maximum-parsimony analysis produced four clusters: (1) all Oidiodendron species (at least 90% similarity); (2) all five Victorian dark grey-olive isolates (at least 96% similarity); (3) one Victorian isolate and Cistella grevillei (88% similarity); (4) two light-coloured Victorian isolates and H. ericae (81% similarity). This suggests that these isolates from the Epacridaceae do not belong to the same species as those forming ericoid mycorrhiza in the Ericaceae.

The size and distribution of Cortinarius rotundisporus genets at three sclerophyll forest field sites in New South Wales, Australia, were estimated by using microsatellite-primed PCR (MS-PCR) of DNA extracted from sporocarp tissue. MS-PCR fingerprints generated with the primers (GTG)5 and (GACA)4 indicated that two to five genets were present at each site, with each site being characterized by a single large genet (9–30 m in diameter). Analysis of internal transcribed spacer (ITS)-RFLP patterns from individual sporocarps used in the study suggested that three distinct RFLP types were present in the sampled C. rotundisporus population. ITS sequence data indicate that the three RFLP types had less than 88.4% sequence identity to each other, strongly suggesting that C. rotundisporus is a complex of three species.