Volume 94, Issue 2-3
April 1985, pages 85-537
pp 85-90 April 1985
Median periods of saprophytic survival byGaeumannomyces graminis var.tritici in colonized wheat straws are shorter in clay-loams than in soils of lighter texture. This reduction has been ascribed to the microflora of clay-loam soils, and especially to competition by commensal bacteria for the sugars released by fungal cellulolysis of the wheat-straw tissue. Model experiments on the growth of colonies of four cereal foot-rot fungi on filter-paper in the presence of bacteria showed that the slowly growing colonies ofG. graminis var.tritici caused a loss in paper dry weight that was nearly five times as great, per unit area, as that by colonies ofFusarium culmorum, which grow four times as fast in the presence of bacteria. By their rapid uptake of sugars, commensal bacteria prevent the regulation of cellulase enzyme induction by catabolite repression, so that cellulolysis continues at a maximum rate. So this bacterial competition for sugars hastens exhaustion of the substrate and thus shortens survival of the take-all fungus.
pp 91-97 April 1985
Soils were sampled for over two years from two blocks with differeing rotational history in a paddock at Newdegate, Western Australia to assay for propagule numbers of the take-all fungus and disease severity. Grasses were found to be capable of carrying the pathogen effectively and were almost as hazardous as the cereal crop in the perpetuation of the inoculum. The effects of time on the most probable number (mpn) and the disease severity assay (dsa) were mostly similar. There appears to be a drop in both these measurements during certain periods, commonly in August/September and in May/June. There is also an unexpected increase inmpn anddsa during the summer months.
pp 99-109 April 1985
Although mycorrhizas are diverse in structure they fall into two physiological groups. Those in which the host provides carbon compounds and those in which the fungus does so. The fungi may belong to any of the great taxa, but those of each taxon do not necessarily form one kind of mycorrhiza or consort with particular taxa of hosts. The species of fungi are not specific to any species of host, and although genera of fungi may be restricted to families or genera of host, most are of very wide host range. Some species or strains of fungi can form mycorrhizas of different structure with different hosts and some hosts may form different kinds of mycorrhiza with different fungi.
Those fungi which consort with hosts which provide carbon compounds have a very limited ability to degrade or use complex carbon polymers. Those that provide the carbon for their symbioses are active in such breakdown. Both kinds may penetrate between or into the cells of the hosts without causing death of cells. This problem is discussed and one hypothesis suggesting a means of penetration by the former, and the prevention of tissue destruction by the latter is put forward
pp 111-127 April 1985
The production of fruitbodies of fungi forming sheathing (ecto-) mycorrhizas with trees depends upon current supplies of host assimilates, upon host genotype and the age of the host tree, upon soil types and soil amendments, and weather.
Fruitbodies are not produced by fungi on roots severed from their tree, nor are they produced when trees are naturally or artificially defoliated. As trees, planted in ‘new’ sites, increase in age a succession of fungi produce fruitbodies, most arranged in annuli (rings) but some are arranged linearly, seemingly along secondarily thickened roots. From the initial ‘focus’, a stem base, each ring progresses outwards at rates comparable to those of grassland fairy ring fungi (10–20 cm yr−1), the movement of different rings being spatially correlated. Around birch trees in brown earth soils, rings of early stage fungi (Hebeloma crustuliniforme andLaccaria tortproximalis) are followed by those ofLactarius pubescens, Cortinarius spp. andRussula grisea. This pattern of development is likely to be different when seedlings grow in soil permeated with mycorrhizal roots of old (living) trees as happens during natural regeneration.
Whereas more fruitbodies ofInocybe petiginosa were produced in association with one clone ofBetula pubescens than with another, the reverse was true ofLaccaria tortilis. There is evidence to suggest that soil type may influence the types of early-stage fungi producing fruitbodies. Applying lime to a Scots pine plantation decreased the production of fruitbodies byPaxillus involutus andLactarius rufus; applying ammonium-N stimulated fruitbody production byPaxillus involutus but decreased that ofAmanita muscaria and some species ofRussula.
Seasons favouring the production ofPaxillus involutus fruitbodies were different from those favouringLactarius rufus. Fruitbody production of the late stageAmanita muscaria, in plantations ofPinus patula, was directly proportional to amounts of rainfall after an initial threshold which was smaller in old, than in young, plantations.
pp 129-135 April 1985
Forage grasses (e.g., Lolium spp. andFestuca spp.) have long been known to harbour fungi which maintain an intercellular relationship with leaf tissue of the host. These endophytic fungi are considered to be the source of toxins which accumulate in infected grasses and are the cause of physiological disorders in grazing sheep and cattle. On the other hand, these same endophytes contribute to the resistance of the host plant to certain pests. Few investigators have examined the extent to which the fungal endophyte invades different parts of the grass. Our studies have recently concentrated on the mechanism by which the endophytes ofF. arundinacea andF. versuta invade the embryo and thus establish residence in successive host generations.
pp 137-148 April 1985
General characteristics of ambrosia fungus-beetle mutualism are described and recent trends for innovative research briefly indicated. Techniques to locate, collect, transport, maintain, isolate, and study fungi and beetles in the field and in vitro are reviewed in detail. A synthetic basal medium for growing ambrosia fungi is described; this should enable researchers to investigate nutrition and enzymology of both the symbionts.
pp 149-163 April 1985
The soil keratinophilic fungi are responsible for the breakdown of any keratin containing wastes such as hair, fur and feather. These fungi therefore play a significant role in the breakdown of soil debris. In this review we have evaluated the information available on ecological factors governing the distribution and growth of keratinolytic fungi.
pp 165-173 April 1985
Pregerminative polarization of the cytoplasmic content of a spore following its awakening by water imbibition is ultrastructurally featured by a 2-step sequential process: (i) general partition into a vacuole-enriched pole endowed with increased turgor pressure opposite to an energized pole of clustered mitochondria; such mitochondrial positioning would predetermine the bulging site of the germ tube by optimizing the chance event of (ii) physical contact between that plasma membrane site with the membrane of a few of the most peripherically located mitochondria of the cluster. In such a membrane interaction, the plasma membrane would presumably be electrically depolarized by mitochondrial protons vectorially extruded towards its negatively charged inside face acting as proton sink. That primary spatio-physical event would set off a train of events, the first being a local acidification of the thereby gelified cytosol excluding mitochondria while attracting vesicles into this prospective hyphal tip.
It is further suggested that the primary axiation of the germinative conidium can be controlled by slight changes in the peripheral O2 tension guiding the mitochondrial cluster towards the elected membrane site of germ tube outgrowth.
pp 175-196 April 1985
Microbial enzymes of thermophilic fungi offer several advantages since they are highly thermostable and also have minimum chances of fermenter contamination at elevated temperatures. In this review, we have focussed on the proteases and lipases of thermophiles together, because of their wide ranging applications in the field of brewery, textile, dairy, pharmaceutical and leather industries.
pp 197-207 April 1985
The family Gymnoascaceae, is related to the dermatophytes. Anamorphs of certain members lie inChrysosporium, Microsporum andTrichophyton. The members of the family are world wide in distribution. They live as saprophytes on various Keratinous substrates, dung, droppings and in soil. Often they are isolated from clinical sources of human and animal. Therefore these fungi have been regarded as “potential pathogens and opportunistics”. Thus the family is important. Studies on Gymnoascaceae have been mostly confined to morphological and taxonomical details. Investigations on the physiology of its various members are limited, though such studies are called for. The present paper reviews the physiological studies so far conducted in the family dating back to the year 1893. The early investigators confined their studies to nutritional requirements of certain species. Later workers employed nutritional biochemical behaviour of different species and strains as a parameter for clarifying taxonomic confusions. The biochemical behaviour is genetically controlled and may have a bearing on taxonomy. More recently a theoretical study was undertaken to analyse the growth patterns quantitatively. Equations for growth curves of certain species were obtained. The relevance of undertaking such numerical methods is appreciated in view of the facts that these predictions can give clues on certain taxonomical and behavioural patterns.
pp 209-227 April 1985
An attempt is made at a unified morphological analysis of the hyphomycetous anamorph as seen in its two phenotypic expressions: the vegetative (=hyphae and mycelia) and the reproductive (=conidiophores, conidiogenous cells, proconidia and free propagules). (Multi-hyphal structures are ignored). A distinction is made between cytological and structural criteria. The basic units used arecells (or compartments), and their assemblage intohyphae, and at a higher level of organization,organs. The description ofelements (=the simplest recognisable structures) is suggested for cases where compartments are absent or poorly defined. Eight independent characters are proposed for the description of the mature anamorph. A unified approach is also suggested for the study of the development of the anamorph. Basic, general processes are growth (=different combinations of elongation, branching and transformation), maturation, lysis and secession (as defined in this paper), and, in the case of recognizable compartments, cell division (=septation). These processes, when integrated in various specific sequences, result in well known patterns, seen in both vegetative development and asexual reproduction. Examples are drawn from species with ameroconidia, more intensively studied in recent literature, as well as on lesser known species with simple, septate, or compound conidia. Some criteria are proposed for an ordered observation of independent processes which could provide a basis for a more stable descriptive terminology.
pp 229-244 April 1985
The generic namesChelisporium andCheiroconium are reduced to synonymy withSirothecium and three species are accepted.Cheiromycella is briefly reviewed andCheiromyces is maintained with a single species. Its typification is discussed.Dictyosporium is briefly discussed and a new species,D. australiense, is introduced. The nameD. subramanianii sp. nov. is proposed for the invalidly publishedD. intermedium andD. circinatum is transferred toHelicorhoidion. Digitodesmium is doubtfully kept distinct fromCheiromyces.
pp 245-252 April 1985
The taxonomic status of the anamorph genusCirrenalia is reviewed. As presently constituted, the genus is comprised of five marine and five terrestrial species. Descriptions of the species are given and a dichotomous key to species provided.
pp 253-257 April 1985
Porosubramaniana Hol.-Jech., a new genus of porosporous dematiaceous Hyphomycetes is described to accommodate a new speciesP. moniliformis Hol.-Jech. occurring on decayed wood in Poland.
pp 259-267 April 1985
A new coprophilous HyphomyceteBasifimbria spinosa Buffin and Hennebert is described. The fungus is characterized by sympodial conidiophores producing two intergrading types of successive blastoconidia. The onesArthrobotrys-like, unseptate, elliptical and smooth, born on successive denticulate swelling apices of the conidiophore; the others areBasifimbria-like, sphaerical and spinose, born on irregularly denticulate zig-zag conidiophores. The whole range of the conidiogenetical variation may occur on the same conidiophore. This pleoanamorphic fungus is, however, given one binomial only.
pp 269-272 April 1985
Two dematiaceous hyphomycetes,Spadicoides subramanianii sp. nov. andDwayabeeja aethiopica sp. nov., collected on dead twigs from Ethiopia are described and illustrated.
pp 273-280 April 1985
Conidia ofAcremonium polychromum and of the anamorph ofWallrothiella subiculosa were studied withtem. The conidia ofA. polychromum have a very thick, fibrous, electron-dense outer layer, which finally becomes coarsely warted. InW. subiculosa this layer remains thin and more compact and becomes minutely roughened. Because of these differences and the regular pigmentation of the vegetative hyphae and phialides, a new genus,Pseudogliomastix, is described for this anamorph. The differences between pigmented and hyaline conidia among species ofAcremonium sect.Gliomastix do not seem to be so fundamental as to preclude their inclusion in one genus,Acremonium.
pp 281-308 April 1985
Conidial development inArthrinium and similar genera with basauxic conidiophores is reviewed and compared with that ofNigrospora. A hypothesis is erected to explain the nature of the basauxic conidiophore type of development. Predictions are made from the hypothesis, and are tested using species ofChalara, Mammaria, Wardomyces and selected other hyphomycete genera as examples. It is concluded that, to classify these hyphomycetes, a system is required which would completely cross the boundaries of the traditional classifications of Saccardo and Hughes.
pp 309-317 April 1985
A new sclerotium-producing species on an ant host,Hirsutella subramanianii, and a newCordyceps species,C. cantharelloides, with agaric-like fruitbodies on a wood-boring coleopteran larva are described and illustrated from specimens collected in the Amazonian rain forests.
pp 319-339 April 1985
The classification of the Ascomycotina remains one of the major problems in systematic mycology. A survey of the various systems proposed over the last five decades is presented identifying their key aspects. A table including outlines of 20 systems is provided. Constraints to developing a generally acceptable system are identified as arising from the size of the group, its geological age, assumption of phylogenetic concepts, data availability, convergence, delimitation of genera, and taxa remaining to be discovered. Progress towards an acceptable system must pay due regard to the users of taxonomy and have strong elements of stability. Data collection could be approached by concerted efforts of groups of specialists tackling particular orders in turn. It seems most appropriate to progress by building up the hierarchy from maximum information content groups, concentrating on delimiting monophyletic units in the ranks of order and family, and restricting hypothetical overall systems to specialist debate rather than recommending them for general use.
pp 341-345 April 1985
The generaChaetomium andAchaetomium cannot be distinguished by the presence or absence of ascomatal hairs, but only by a combination of other characters. SeveralAchaetomium species are transferred toChaetomium. A new genusSubramaniula is proposed forAchaetomium thielavioides.
pp 347-354 April 1985
A foliicolous fungus occurring onSyzygium in the Nilgiris and previously recorded asMeliolina mollis (Berk. & Br.) v. Höhn. is redescribed asM. subramanianii sp. nov.
pp 355-361 April 1985
A new marine Ascomycete,Caryosporella rhizophorae Kohlm. gen. et sp. nov., is described from dead wood of intertidal roots and branches ofrhizophora mangle growing on three small islands off the coast of Belize (Central America). The new genus is compared withCaryospora, and its placement in the Melanommatales and Massariaceae is discussed. The new species is considered to be an obligate marine fungus, but because of its taxonomic position it belongs to the group of secondary marine fungi that originated from terrestrial ancestors.
pp 363-367 April 1985
A new ascomycetous genus,Pseudascozonus, related toAscozonus andThelebolus, is proposed withPseudascozonus racemosporus, sp. nov. as type species.
pp 369-380 April 1985
Species of the Hymenochaetaceae (Fungi, Hymenomycetes) are presumably homothallic and consequently of only uniparental reproduction. The number of species described is high (more than 100 inHymenochaete, several hundreds inPhellinus, etc. and their classification may be successful only when a clear species concept is consistently used. Type studies may give some help mainly for nomenclature; for taxonomy the study of numerous specimens of each species and a statistical approach is needed.
The biological species concept is inapplicable to uniparental fungi; its indirect application mentioned by some evolutionists is unrealizable. The recognition of sibling microspecies on the basis of the selection species concept is the proper foundation for the taxonomy of the Hymenochaetaceae.
By way of examples the taxonomy of several pairs of closely related Hymenochaetaceae species is discussed (H. mougeotii andH. murashkinskyi; H. rheicolor andH. attenuata; H. semistupposa andH. yasudai; Phellinus laevigatus andPh. orienticus; Ph. pini andPh. chrysoloma; Phylloporia ribis andPh. ephedrae). A new combinationPhylloporia ephedrae (Voronich.) Parm. is proposed.
pp 381-386 April 1985
Chemical characters prove to be more and more useful for the taxonomy of Agaricales. Nucleic acids and proteins have only sporadically been studied in Agaricales. Secondary metabolites, particularly pigments, however have been used in many families. Several examples are discussed, particularely fromCortinarius. The possibility to derive new ideas from correlations between chemical, mycogeographic and ecological characters is discussed.
pp 387-406 April 1985
Epidemiological studies of rusts of wheat were first taken up in India by Mehta who showed that due to intense summer heat the inoculum of rusts in any form is completely destroyed in the plains during the summer months. But the rust survives in the hills of North and South India. Recent work has identified different foci of infection and has shown that the primary source of stem rust lies mainly in the South Indian hills and that the North Indian hills contribute very little, if at all. Stripe rust, on the other hand, comes mainly from the northern hills while leaf rust is contributed both by southern and northern hills. This view is supported by detailed studies of temperature profile, incubation period, disease gradient etc. Moreover, it has been shown that the cyclones in the Bay of Bengal play a very vital role in dissemination of stem and leaf rusts from Nilgiri and Pulney hills. The ground survey data and information collected through rain sampler, satellite television cloud photography etc. are being utilized for developing bioclimatic models and linear prediction equations. For the disease management, erecting genetical barriers through gene-deployment has been suggested.
pp 407-413 April 1985
The present investigation has shown that the leaf spot of pearl millet (Dactuliophora leaf spot) caused byDactuliophora elongata has been erroneously named as zonate leaf spot and the causal agent misidentified asGloeocercospora sp. by Williamset al (1978) and Sundaram (1980). The symptoms of Dactuliophora leaf spot are different from those of “true” zonate leaf spots of sorghum and pearl millet caused byGloeocercospora sorghi. The zonate leaf spot pathogen,G. sorghi, produces few to many septate, hyaline, elongate to filiform conidia but no conidia are produced byD. elongata. InG. sorghi, sclerotia are produced sub-epidermally and germinate in 3–7 days by producing sporodochia. InD. elongata, sclerotia are produced on fully erumpent sclerotiophores and germinate in 4–8 hr by producing germ tubes all over the surface.
pp 415-431 April 1985
Plant diseases caused byRhizoctonia solani are generally managed by use of fungicides as seed and/or soil treatments. Disease control is reported to vary on different crops by the same chemicals on account of their use in different seasons and regions. Reasons for such a diversity in the efficacy of fungicides have been determined in some cases and these have been attributed to variations in soil characteristics like reaction, texture, moisture and cation exchange capacity, etc. In addition, the interaction of fungicides with fertilizers, manures, herbicides and insecticides applied to the crop have also been a cause of such a variation. The limitations of fungicides to controlR. solani diseases satisfactorily under diverse crop habitats and their interactions with other agrochemicals have been discussed
pp 433-436 April 1985
Records of mycotic keratitis caused byCylindrocarpon species are increasing,C. vaginae is described as new and related toC. lichenicola.
pp 437-451 April 1985
The conidial ontogenesis and the pathogenicity of the pathogenic black yeasts for mice are described. Scanning electron microscopy of conidiogenesis, physiological and biochemical characteristics and histological findings of infected mice are described in this paper.
pp 453-463 April 1985
Four species ofDrechslera usually soil saprophytes or plant parasites were recognized over the last few years as agents of deep mycoses with subcutaneous, osteolytic, endocardic and pulmonary localizations as well as superficial mycoses of cornea and skin. The key of the potentially pathogenic fungiDrechslera longirostrata (agent of an endocarditis and spondylodiscitis),Drechslera hawaiensis (agent of a pulmonary mycosis)D. rostrata andD. spicifera (agents of several cases of phaeohyphomycoses) is described. The sensitivity of these species to actual systemic antifungal agents (amphotericinB, ketoconazole, itraconazole) is reported.
pp 465-474 April 1985
The green revolution is here to stay. It must now be taken to its next logical step which is one of closing the continuing yield gaps. The present production advance is based on sound policy decisions, more of which will be needed. Its fundamental basis is the creation of high genetic potentials of crop yields and of new agronomic environments through the use of modern farm inputs for the expression of these potentials on farmers fields. The enhancement of this expression calls for the development of a new management infrastructure to provide a wide range of services to millions of our small and marginal farmers. India’s changing agriculture also brings in its wake new problems. One of the more important of these relates to its increasing genetic uniformity. This makes our agriculture more vulnerable to diseases and pests. A major programme of genetic diversification and conservation of genetic resources is suggested to overcome this problem.
pp 475-485 April 1985
The colourless, stigma-free flagellatePolytomella magna which does not show natural responses to light becomes sensitive to light in the presence of photodynamically active dyes, such as riboflavin, methylene blue, toluylene blue, thionine, toluidine blue, neutral red and rose bengal, provided that oxygen is present. This reaction resulting in a light avoiding response depends neither on the absorption characteristics nor on the redox properties of the dyes. Detailed studies with methylene blue have shown that this response depends on the photon fluence rate and the dye concentration as well. The action spectrum of the photodispersal calculated on the basis of photon fluence rate-response curves is essentially identical with the absorption spectrum of methylene blue,i.e. no responses occurred below 530 and above 700 nm. Pre-irradiation experiments have shown that methylene blue is photobleached and, hence, inactivated in the presence but not in the absence of oxygen. Moreover, it has been demonstrated that the methylene blue mediated responses are chemotactic rather than photophobic ones. These experiments confirm the results of earlier investigations with riboflavin.
pp 487-504 April 1985
A high percentage ofDNA sequence noted in higher organisms is highly repetitive in nature. Such sequences may be highly homogeneous, moderate, minor and inverted. Those sequences are found in different loci including introns, spacers, transposons, in addition to their interspersion with unique sequences. Such sequences share the property of amplification, dispersion and possibly mobility. The term ‘DynamicDNA’ has been proposed to account for their varied property. Their presence may account for “C Value Paradox” in eukaryotes. Evolutionary advance is also associated with increase or decrease of repeated sequences.
pp 505-523 April 1985
Strand plant-communities, other than the mangroves, composed of psammophytes, halophytes have been described along with bioclimatic, edaphic factors for the seven coastal biogeographic sub-divisions of the sub-continent.
pp 525-537 April 1985
Flower initiation is an important morphogenetic event. In this brief review the formative, ultrastructural, cytological and biochemical changes that occur in the transitional meristems in a few selected species have been discussed. In the evoked meristems, the number of plastids, mitochondria and ribosomes are usually higher. Further, an early shift of 4C nuclei to the 2C value, an increase in respiration and enhanced activities of dehydrogenase and phosphatase have been observed. The molecular events that ensue immediately after induction need further study.
The factors that regulate flower morphogenesis in vitro and reversal of excised flower buds to vegetative growth have been discussed. Reports on the modification of inflorescence development through the application of growth regulators have been analysed.