摘要:

ABSTRACTHigh yields (approx. 108/ml) of protoplasts of high purity (>99%) can be obtained from young thalli of strains T12 and T95 ofTrichoderma harzianumby digestion of cell walls with NovoZym 234. Protoplasts derived from mycelium or immature conidia contained 2–12 nuclei. After resuspension in 0.6 M sorbitol, 10 mM CaCl2, and 10 mM Tris-HCl at pH 7.5 (STC) about 10% of the protoplasts regenerated on osmotically stabilized medium. Protoplasts fused by a step-wise addition of polyethylene glycol (PEG) also regenerated readily. Fusion between lysine-requiring and histidine-requiring auxotrophs of strain T95 gave rise to about 10% as many colonies on basal medium (BM) as on BM amended with histidine and lysine (BM + HL). Conidia from these prototrophic colonies were nearly all auxotrophic. Approximately equal numbers required histidine or lysine. These results indicate that the prototrophic progeny of this fusion were balanced heterokaryons with the parental nuclei present in equal numbers. Conversely, fusion between T12 his and T 95 lys gave rise to unbalanced heterokaryons with T12 predominating. The frequency of prototroph formation was less than 0.01% and the original isolates grew very slowly. These expressed only the isozyme phenotype of the T12 parent at four loci but the T95 genome was detected in sectors and single-spore isolates. Subsequently, various non-parental progeny were recovered. Some were of the T95 isozyme phenotype, while others were of the T12 phenotype. None showed isozyme patterns indicative of expression of both genomes. Growth rates ranged from greater than that of either wild type parent on any medium to very slow growth rates even on permissive media. Morphologies ranged from wrinkled, brown, nearly asporulent types recognizable asTrichodermaonly by isozyme phenotype to ones similar to the wild-type parental strains. Many nonparental strains remained unchanged when propagated from single conidia, indicating that these nonparentals were homokaryotic. Others yielded a variety of parental and nonparental single-spore isolates, indicating complex heterokaryosis.

ISSN:0027-5514    

DOI:10.1080/00275514.1988.12025515

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

ABSTRACTDidymium iridismyxamoebae and Plasmodia were cultivated in liquid peptone-glucose-yeast media or on plain agar withEscherichia colikilled by mild heat treatment. Fifteen of sixteen heterothallic strains could be maintained by serial transfer on the axenic medium. There was no difference in mating and sporulation frequency between never axenized strains and axenic strains reassociated with live bacteria at the time of mating. Axenic strains mated under axenic conditions formed plasmodia at the same frequency as the above crosses but the sporulation frequency was reduced by one-half.

ISSN:0027-5514    

DOI:10.1080/00275514.1988.12025516

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

ABSTRACTThe storage of inoculum (mycorrhizal spores and roots in soil) as prerequisite treatment for increasing axenic spore germination was investigated with a tropical isolate ofGlomus clarum.Prolonged dry storage of the inoculum, for up to 6 months at 25–30 C, increased percentage spore germination significantly on water agar. If, following dry storage, the extracted spores were then stored at 4 C for at least 2 weeks, germination was further enhanced. Incubation temperatures of 25–35 C and medium pH of 5–8 were most favorable for germination. These requirements may be significant in understanding the ecophysiology of vesicular-arbuscular mycorrhizal fungi in their natural environment.

ISSN:0027-5514    

DOI:10.1080/00275514.1988.12025517

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

ABSTRACTThe ultrastructural responses ofTaphrina deformansto 0.073μg ml-1propiconazole were studied as a function of incubation time with the inhibitor by transmission electron microscopy, and compared to those of the corresponding controls and an isolate that exhibited some tolerance to the inhibitor at 0.5μg ml-1. The principal responses relative to the control included: 1) thickened and layered cell walls with the outer layer being more electron dense and fragmented, 2) invaginated or convoluted plasma membrane, and 3) granules and membrane vesicles entrapped in the cell walls. These responses were apparent after 24 h incubation with the inhibitor, but not at 12 h, and became progressively more pronounced and frequent in cells with time up to 72 h. Partially tolerant cells exhibited essentially the same characteristics, but they were generally more pronounced than in the relatively sensitive cells. Growth of the cells in the presence of propiconazole either had no effect on cell wall glucosamine content (used as an indicator of chitin) or it resulted in an increase.

ISSN:0027-5514    

DOI:10.1080/00275514.1988.12025518

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

ABSTRACTFrequencies of isolation and occurrence of 24 fungal taxa from washed root and shoot pieces ofSalicornia europaeaare variable over plant collections made along a conductivity gradient represented by four halomorphic sites in western Manitoba and central Saskatchewan. Assemblage dominance, a chi-square derived coefficient of association between sites, ordination of percent stress, disturbance and competition contributed by taxa in life strategy spectra of the assemblages, sum of squares agglomerative clustering of an Ochiai index distance matrix, concentration analysis of site and species scattergrams and environmental data across the sites distinguish three rhizoplane and two cauloplane communities.Among rhizoplane assemblages, ruderals and stress-tolerant ruderals characterize the assemblages from the two sites (respectively Indy and Strap lakes) at the low end of the conductivity gradient. Stress-tolerant competitors represent the principal life strategy from the sites (Shoal and Muskiki lakes) at the higher end of the gradient. Cauloplane fungi are competitors across the sites with additional stress-tolerant competitive elements in the Shoal assemblage and competitive ruderal taxa in the Muskiki assemblage.

ISSN:0027-5514    

DOI:10.1080/00275514.1988.12025519

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

ABSTRACTFour species in the tribe Balansiae (Clavicipitaceae) infecting grasses and sedges were studied to determine their growth habit as endophytes or epiphytes. The genusMyriogenosporapreviously has been reported to be epiphytic but other members of the tribe have been presumed to grow endophytically in their hosts. Cultural and histological studies indicate that the speciesAtkinsonella hypoxylonandBalansia cyperioccur as epiphytes around meristems, young leaves, and inflorescences of their hosts. In contrast,B. epichloëandB. henningsianagrow endophytically within host tissues. Non-clavicipitaceous endophytic fungi were isolated from most host plants examined. The possible origins of endophytic and epiphytic growth habits and their biological consequences are considered.

ISSN:0027-5514    

DOI:10.1080/00275514.1988.12025520

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

ABSTRACTThe phyllosphere mycoflora ofC. incanus L., A. unedoL. andQ. cocciferaL. and its seasonal variation were studied by means of a tape impression culture method.The number of colonies per cm2was highest on leaves ofC. incanusand lower onA. unedoandQ. coccifera.The seasonal fluctuation of 27 fungal forms is illustrated. The dominant fungal species wereAspergillus niger, Cladosporium cladosporioides, Mucor hiemalis, Penicillium frequentans, P. funiculosum, P. verrucosum, Rhizopus stoloniferandTrichoderma pseudokoningii.The abundance of each fungal species was different in the four seasons.There were 6 resident fungal specics:Alternaria alternata, A. flavus, A. versicolor, C. cladosporioides, T. pseudokoningiiand white sterile mycelium.

ISSN:0027-5514    

DOI:10.1080/00275514.1988.12025521

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

ABSTRACTSeasonal abundance and dormancy were examined in field-collected spores of the vesicular-arbuscular mycorrhizal fungus (VAMF)Gigaspora gigantea.Monthly collections of soil were made from a sand dune in Rhode Island from Aug, 1984, through Nov, 1985, andca.weekly collections were made from Aug, 1985, through Jan, 1986. Spore abundance (spores/100 cc soil) increased from July onward, and reached a maximum in Dec, indicating that the majority of spores were formed in late summer and fall. A Sept increase in spore abundance was part of a highly significant cubic trend. Percent germination of spores was highest (89–98%) from Dec to July and lowest (4–9%) in Sept and Oct. Decline in spore germination in Sept, 1984, and Sept, 1985, was highly significant, and germination between Aug, 1984, and Nov, 1985, was best described by a quartic equation. Spores collected in Sept, 1986 were dormant, but were released from dormancy by incubation at 5 C for 5 wk. Dormant spores stored at 20–25 C for 5 wk did not germinate. Approximate length of the dormancy period in the field was 2–9 wk. Monthly mycorrhizal inoculum potential (MIP) values of sand dune soil varied seasonally, ranging from 13.9% to 49%, with minimal VAMF colonization in Sept and Oct, similar to the spore germination pattern ofG. gigantea.

ISSN:0027-5514    

DOI:10.1080/00275514.1988.12025522

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

ABSTRACTThe holotype collection forCordyceps canadensiswas found to be composed of two taxa, differing primarily in the length of the ascospore segments. A lectotype, corresponding to the original description, is designated. The nameC. capitatahas been applied to the same two taxa. A neotype is designated forC. capitata, andC. canadensisis placed in synonymy. The taxon with longer ascospore segments, often misidentified asC. canadensis, is namedC. longisegmentis sp. nov.

ISSN:0027-5514    

DOI:10.1080/00275514.1988.12025523

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

ABSTRACTNew taxa proposed areRamaria cystidiophoravar.anisata, R. distinctissimavar.americana, R. foetida, R. highlandensis, R. hilarisvar.olympiana, R. schildii, andR. spinulosavar.diminutiva.Species circumscriptions forR. claviramulataandR. verlotensisare furnished based on additional collections.Ramaria fibulatais proposed asstat. nov., andR. subspinulosais considered separate fromR. spinulosa.

ISSN:0027-5514    

DOI:10.1080/00275514.1988.12025524

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor