ISSN:0027-5514    

DOI:10.1080/00275514.1992.12026167

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

ABSTRACTNitidulid beetles (Carpophilusspp.) and vinegar flies (Drosophila melanogaster) from stone and pome fruit orchards readily acquired propagules of + and−mating types ofMucor piriformisfrom decayed fruit and transmitted them to healthy fruit on which zygospores developed. Higher numbers of decayed fruits on the orchard floor resulted in increased acquisition of + and−mating types ofM. piriformisby vinegar flies and vice versa. In controlled laboratory and field experiments, nitidulid beetles and vinegar flies acquired propagules of + and−mating types ofM. piriformisand carried them on healthy peach and nectarine fruits, resulting in fruit infection and development of zygospores ofM. piriformis.Propagules of + and−mating types ofM. piriformispersisted for at least 11 days on natural populations of vinegar flies after exposure to fruit decayed byM. piriformis.Numbers of zygospores developed on fruit exposed to contaminated nitidulid beetles and vinegar flies varied considerably from fruit to fruit as did numbers of zygospores resulting from contaminated insects plated in dishes containing acidified potato-dextrose agar. Several zygospores ofM. piriformisdeveloped on peaches as a result of insect activity germinated in 15% of the fruit placed in the field during the winter.

ISSN:0027-5514    

DOI:10.1080/00275514.1992.12026168

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

ABSTRACTDecrease in osmotic potential of growth media resulted in changes to vesicle and conidial morphology inCylindrocladium scoparium, C. floridanumandCylindrocladiella camelliae.Radial growth and the presence of chlamydospores also decreased for these species when the osmotic potential of the growth medium was decreased. Vesicle shape varied on different culture media as well as with age and conditions of incubation. Extended incubation periods induced a change in osmotic potentials of the culture media directly influencing vesicle shape. Carnation-leaf agar is proposed as a standard medium for the characterization of morphological criteria inCylindrocladiumandCylindrocladiella.Moreover, an incubation period of 7 days at 25 C under alternating light and dark cycles is proposed for vesicle examination.

ISSN:0027-5514    

DOI:10.1080/00275514.1992.12026169

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

ABSTRACTThis study used polymerase chain reaction amplification and direct sequencing of double-stranded DNA to compare the intergenic region between the 3′end of the 26S gene and the 5S gene of the nuclear, ribosomal DNA of several northern hemisphere species ofArmillaria.The aligned sequences were scored for base substitutions and phylogenetic relationships among species were analyzed by parsimony. We concluded 1) that the intergenic region sequences ofA. ostoyae, A. gemina, andA. borealisare more closely related to one another than to any other species; 2) that the intergenic region sequences ofA. lutea, A. calvescens, A. cepistipes, A. sinapina, species IX and species X constitute a closely related group distinguishable from those ofA. ostoyae, A. boralis, andA. geminaby a significant number of substitutions; and 3) that the morphological divergence inA. melleaand Atabescensrelative to the majority of northern hemisphere species and to each other has been roughly paralleled by divergence in the intergenic region, which aligned poorly in all interspecies comparisons includingA. melleaandA. tabescens.A byproduct of this study was the identification of several substitutions in the intergenic region sequence that could potentially provide the basis for rapid species diagnosis.

ISSN:0027-5514    

DOI:10.1080/00275514.1992.12026170

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

ABSTRACTA mitochondrial DNA restriction map was prepared for a strain ofClavicorona pyxidatausing three enzymes, Hind III, Hpa II and Xba I. Hybridization withSuillusprobes and yeast petite mutants established the location of ribosomal RNA genes, areas putatively associated with cytochrome c oxidase complex subunits I, II and III, cytochrome b and ATPase subunits 6 and 9. Genome size was estimated from restriction fragment digests at 56 kb.

ISSN:0027-5514    

DOI:10.1080/00275514.1992.12026171

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

ABSTRACTThe effects of tallgrass prairie management practices, burning, mowing (simulated grazing), and fertilization, on mycorrhizal symbiosis were studied in a field experiment established in 1986. In 1987 and 1989, there were no significant effects of these management practices on mycorrhizal fungus species composition. While 14 and 11 species were observed in 1987 and 1989, respectively, the dominant species in both samplings wasGlomus ambisporum.Spore numbers were generally not affected by these management practices. However, in 1987 there were significant effects on spore number due to nitrogen addition and a burn×mow interaction, but these were not apparent in 1989. In 1989 there was a significant burn×nitrogen interaction, with nitrogen fertilization of unburned plots significantly increasing the number of mycorrhizal fungal spores. In winter months total % root colonization, active % root colonization and inoculum potential were low whether or not plants were fertilized. In contrast, in late spring and early summer when plants were actively growing, fertilization reduced total % root colonization, active % root colonization, and inoculum potential in soil. However, nitrogen fertilization was not as inhibitory to the symbiosis as phosphorus fertilization or phosphorus + nitrogen fertilization. The negative effects of nitrogen fertilization on mycorrhizae are probably offset by the pronounced benefit of nitrogen fertilization to plant biomass production.

ISSN:0027-5514    

DOI:10.1080/00275514.1992.12026172

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

ABSTRACTA stimulatory effect ofBoletinellus merulioideson the roots ofPinns densiflorawas evaluated using pure culture synthesis. Seedlings ofP. densiflorawere inoculated with cultures ofB. merulioidesat high and low glucose levels. After 180 days, shoot weight was not enhanced over controls by inoculation with the fungus, but root weight was significantly increased and roots were highly branched. Short roots were dichotomously branched, lacked root hairs, and had an internal morphology similar to that of ectomycorrhizal rootlets. A loose weft of fungal hyphae surrounded the short roots, but did not penetrate the epidermis. Higher glucose levels further increased root weight and branching. Filtrates from liquid-grown cultures ofB. merulioidesandPisolithus tinctoriuswere compared using high performance liquid chromatography. Both fungi produced measurable quantities of indole-3-acetic acid, the in-vitro production of which was enhanced by higher glucose levels.

ISSN:0027-5514    

DOI:10.1080/00275514.1992.12026173

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

ABSTRACTPseudotracylla falcata, from dead leaves and rotten fruit ofVaccinium macrocarponin Massachusetts and New Jersey, is described as the second species in the genus. Pycnothyria of the type species,P. dentata, have upper and lower walls connected by a central columella. A detailed account of pycnothyrial development is given based on study of these two species.

ISSN:0027-5514    

DOI:10.1080/00275514.1992.12026174

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

ABSTRACTFour mating populations, each associated with a distinct asexual stage (anamorph), are presently recognized withinGibberella fujikuroi.We have identified a fifth mating population, termedGibberella fujikuroimating population F, and have correlated it with theFusarium moniliformeanamorph. We have developed female-fertile tester strains that permit reliable detection of other members of this mating population through sexual crosses made under laboratory conditions. Members of this mating population are widely distributed geographically and have been recovered from several states in the United States, the People's Republic of China, Thailand, and the Republic of South Africa.

ISSN:0027-5514    

DOI:10.1080/00275514.1992.12026175

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor

摘要:

ABSTRACTHalophytophthora exoproliferais described from decaying mangrove leaves in coastal marine environments. It was discovered wholly independently and nearly simultaneously in Atlantic and Pacific mangrove systems, both near latitude 26°N. Key characteristics that distinguishH. exoproliferafrom other species ofHalophytophthoraare: a) sporangial dehiscence tubes containing clear closure material that rapidly expands outward and immediately dissolves at zoospore release; b) external proliferation of the sporangia; and c) readily produced sexual structures.

ISSN:0027-5514    

DOI:10.1080/00275514.1992.12026176

出版商:Taylor&Francis    

年代:1992

数据来源: Taylor