摘要:

ABSTRACTGalls typical ofPeridermium harknessiibut with white aeciospores were found on nativePinus ponderosavar.scopulorumin North Dakota in the same habitat as galls with orange spores. Size and germination characteristics of white and orange spores were similar. Seedling inoculations with white or orange spores and observation of infected trees revealed similar symptom development and virulence levels. Characteristics of cultured isolates derived from white- or orange-spored galls were similar except for color. Isozyme phenotypes of white-spored samples were not significantly different from those of orange-spored samples. These observations indicate that white and orange spore colors are apparently not associated with other measured traits and that the white-spored and orange-spored galls in this stand are phenotypic variants of the pathogen known asP. harknessii.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026008

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTMeasurements of competitive saprophytic colonization were used to evaluate the activity ofTrichoderma harzianumin non-sterile soil under conditions of varying soil moisture and temperature. Estimates of activity based on levels of colonization, determined after homogenization of substrate pieces, were more discriminating than those based on the number of colonized pieces.T. harzianumwas found to be most active at soil matric potentials from -0.5 to -1.0 bar, with activity declining at matric potentials of 0.0, -7.5, and -15.0 bars. The saprophytic activity ofT. harzianumwas greatest at temperatures from 15 to 21 C. The optimum temperature for competitive colonization was several degrees lower than the optimum temperature for growthin vitro.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026009

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTPhysicochemical properties of cell wall surfaces of conidia, conidial germ tubes, hyphal bodies and mycelia of the entomogenous hyphomyceteNomuraea rileyiwere studied. Hydrophobicity was determined using a polystyrene microsphere adhesion assay. Microspheres bound to conidial germ tube and mycelial walls indicating that these surfaces are hydrophobic. Microspheres did not bind to hyphal body walls except at polar areas. Results from these experiments were confirmed using phase exclusion methods.Electrostatic charge characteristics of fungal surfaces were examined using DEAE (positively charged) and CM (negatively charged) beads. Cells from all growth phases adhered to DEAE but not CM beads indicating the presence of negatively charged sites on the surfaces. Degree of electronegativity as shown by FITC-poly-L-lysine binding is greatest on hyphal bodies and at the proximal end of germ tubes. Fluorescence was faint on conidia and mycelia. Cationized ferritin formed a thick capsule around hyphal body cells and a thinner but continuous layer on sheath material surrounding germ tubes; labeling of mycelial sheath was more random possibly due to the dispersed native of this material. Areas of germ tubes or mycelium not covered by sheath were sparsely labeled as were conidial surfaces. Neutralization of hydrophobicity or electronegativity did not affect passive binding of conidial or mycelial cells to monolayers of insect hemocytes.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026010

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTThree species ofTremellaare examined to document their mating compatibility system, confirm their identity as biological species, and define their population structures in terms of mating type allele frequency and distribution. Confirmation of intersterility was made by pairingA1andA2isolates of each of the three presumptive species in all possible combinations. No detectable reaction could be observed when interspecific haploid yeast cells were paired; all isolates intermingled but remained in a budding yeast phase. Isolates of the same species produced either clamped, dikaryotic mycelium or conjugation tubes whenever pairings involved unlikeAalleles. Allele frequencies at theBlocus were determined from sample populations for each species. Alleles were recovered in statistically equal frequencies fromT. globosporaandT. indecorata, but significant departure from uniform allele frequency was observed inT. moriformis.T. moriformiswas isolated from ornamental tree species in Davis, California, and was not found outside the city.Ballele diversity is significantly lower in this species than in other species of the genus. Due to the low allele diversity, an introduction of the fungus to the Davis area may have contained most of the alleles of the parental population.Ballele frequency is not uniform and selective pressures over and above those associated with self-incompatibility may be responsible for this observed non-uniformity.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026011

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTFungitoxic effects of the fungusBalansia cyperiinfecting the sedgeCyperns rotunduswere examined. Comparisons of fungal colonizers ofB. cyperi-infected and uninfectedC. rotundusshowedRhizoctonia solanito inhabit leaves from uninfected plants but not leaves fromB. cyperi-infectedplants.In vitrobioassays with solvent extracts ofB. cyperimycelia and culture filtrates showed growth inhibition of test fungi, includingFusarium oxysporumandR. solani.Solvent extracts of leaves fromB. cyperi-infected plants inhibited growth of most test fungi includingF. oxysporum, R. oryzae, andR. solani.Extracts from uninfected plants inhibited the latter two species but to a lesser degree. Results suggest thatB. cyperiinfecting C.rotunduspotentially may deter infection of its host by other more pathogenic fungi.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026012

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTThe growth rates of 32 hymenomycetes and non-hymenomycetes were compared on five media that have been devised for isolation of hymenomycetes. A medium with 2 mg/L benomyl permitted virtually uninhibited growth of hymenomycetes while strongly inhibiting many non-hymenomycetes, but members of the Mucorales and several other species still grew well. Testing of various combinations and concentrations of ingredients led to the use of 2 mg/L benomyl and 2 mg/L dichloran as antifungal ingredients. This was tested in isolations from various field materials and in every case performed as well as or better than other commonly used media.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026013

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTThe development ofCaecomyces communiswas studied with light and fluorescence microscopy.Caecomyces communisis a monocentric fungus which develops to form either a thallus consisting of one or more sporangia attached to a vegetative cell or a mycelioid thallus. During the formation of a vegetative cell with attached sporangia, the posteriorly uniflagellate zoospore encysts and produces a broad germ tube which develops into an incipient vegetative cell. The vegetative cell enlarges faster than the zoospore cyst which develops into an incipient sporangium. A unisporangiate thallus consists of one sporangium attached to a large, vacuolate, vegetative cell. Thallus development may terminate at this unisporangiate stage or further development into a multisporangiate thallus may occur. During multisporangiate thallus formation, the vegetative cell forms one or more outgrowths that become sporangial stalks. Nuclei occur within the vegetative cell and, at maturity, sporangia are formed at the tips of the outgrowths. Often, instead of forming sporangia at the tips of outgrowths produced by the vegetative cell, the outgrowths enlarge into thick filaments. These filaments branch extensively and nuclei occur within the branches. Sporangia are formed at the tips of such filaments which results in a mycelioid thallus. The development and morphology of C.communisandC. equiare compared.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026014

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTSelection and identification of nitrate-nonutilizing (nit) mutants ofAspergillus flavuswas compared on six chlorate-containing agar media. Three isolates ofA. flavuswere used.Nitmutants isolated comprised three phenotypic classes, equivalent toniaD, nirA-, andcnxmutants ofA. nidulans.There were significant differences among isolates and among media in number and types ofnitmutants isolated. The most effective medium contained only nitrate as a nitrogen source, whereas most previously described media for isolation ofnitmutants contain both nitrate and an amino acid. Morphology ofnitmutants was more distinctive on this medium than on other media. The nitrate-only medium yielded mainlyniaDmutants; other media yielded morenirA-mutants, which complementniaDmutants. Fewcnxmutants were found. Use of a nitrate-only medium in conjunction with another medium should optimize isolation ofnitmutants and complementary pairs of mutants.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026015

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTColonization of freshly-fallen leaves by buoyant propagules of aero-aquatic fungi was demonstrated by introducingAcer saccharumleaves onto the surface of a small heterotrophic woodland pond. Subsequent degree of colonization byHormiactis ontariensis, Beverwykella pulmonaria, Pseudoaegerita matsushimaeandHelicodendron triglitziensewas significantly correlated with duration of stay on the water surface. The substrate preferences of these fungi were also investigated.Pseudoaegerita matsushimaeandH. ontariensissporulated more frequently on freshly-abscised, than on year-oldA. saccharumandFagus grandifolialeaves.Beverwykella pulmonariaandH. triglitziensesporulated more frequently on year-oldAcer saccharumleaves than on freshly-abscised leaves of the same species.P. matsushimae, H. ontariensisandH. triglitzienseall sporulated more frequently on freshly-abscised than on year-oldF. grandifolialeaves whileB. pulmonariaexhibited no age preference.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026016

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTThe septal pore apparatus and septum initiation in vegetative hyphae ofAuricularia auricula-judaewere studied by light and electron microscopy for phylogenetic comparisons. Both freeze substitution and conventional chemical fixation methods were employed for electron microscopic studies. Septa developed at the base of the clamp connection and in the main hypha near the clamp where the nuclear divisions had occurred. Septum formation lasted about 4 min. Septal swellings were much larger in chemically fixed than in freeze-substituted hyphae. Fine filaments at the adseptal side of the septal pore cap appeared to be attached to the orifice area of the septal pore and to the cap via intermediate structures. Broader filaments, 7.6 to 9.4 nm in diam, usually connected the plasma membrane bordering the cross wall with endoplasmic reticulum which was continuous with the pore cap. There was a central plate in the septal pore. Ribosomes were absent between the plate and the pore cap. Septum initiation and development involved microvesicles, apparently from the Golgi apparatus, and a third type of filament, 10.6-13.2 nm diam. Septal structure supports the relationship ofAuriculariatoTremellaand functional analysis suggests a general absence of transport of larger organelles between cells, unlike the situation in homobasidiomycetes.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026017

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor