ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026052

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTAleurodiscus gigasporus sp. nov. is characterized by ornamented, broadly ellipsoid basidiospores 29–34(-39)×22–28(-30)μm, abundant acanthophyses, rare monilioid gloeocystidia 6μm diam, and hyphae with clamp connections. It has been collected onKeteleeria davidiana. Aleurodiscus subglobosporus sp. nov.is characterized by subglobose, ornamented basidiospores 19–20(-23)×15–19(-21)μm, abundant acanthophyses, infrequent gloeocystidia about 100×12μm, and hyphae with clamp connections. It has been collected onAbies veichii.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026053

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTRoot colonization as estimated by the line intersect method yields a quantitative value which is related to the extent of intercellular hyphal development and the proportion of the cortex occupied by cells with arbuscules. Hence, by knowing the amount of mycorrhizal colonization, we should be able to predict fungal biovolume provided the relationship (constant) between colonization and fungal biovolume is known. We have used data from morphometric cytological studies of mycorrhiza ofAllium cepaand a chitin assay forAgropyron smithiiroots to determine how colonization and fungus biovolume are related in order to derive the constant (Kf). We show that by using Kfand measuring root radius and colonized root length, we can calculate fungal biovolume and, hence, fungal biomass for an entire root system. We show that the regression model (P<0.0001) for the calculated mycorrhizal fungal biomass value (x) and the actual measured value as determined by the chitin method (y) are good predictors of biomass (y = 0.22 + 1.22x;R2= 0.81). Moreover, we show that when fungal biomass is expressed as percent of the root system, the relationship improves (y = 0.21 + 1.09x;R2= 0.89). This study indicates that it is possible to calculate ultraradical mycorrhizal fungal biomass from colonization data; a preliminary Kfvalue of 0.06 is proposed.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026054

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTBoletus piperatoides, until now only known from Michigan, is shown to have a transcontinental distribution in North America and is not uncommon in northern California. This taxon is transferred toChalciporusand compared toC. piperatuswith which it is most similar. The description ofC. piperatoidesadds new information to the circumscription of this taxon. A technique for identifying collections ofC. piperatoidesfrom herbarium material is also described.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026055

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTThe rust fungusPuccinia substriatavar.indicaproduced germ tubes, appressoria, and substomatal vesicles on seedling and mature leaves of susceptible and resistant pearl millet as well as two nonhost plants, corn and peanut. Lack of directional germ tube growth on peanut leaves appeared to affect the ability of germ tubes to successfully locate stomates. In seedling leaves of the susceptible cultivar Tift 23DB, the fungus produced an extensive system of intercellular hyphae and sporulated abundantly. In seedling leaves of the moderately resistant cultivar 86–8770, necrosis of host cells in response to fungal infection occurred by 2 days post-inoculation. Colonies gradually expanded in size and were associated with macroscopic necrotic flecks with sporulation occurring at 15% of the infection sites. In seedling leaves of the highly resistant cultivar Tift 85DB, fungal colonies were extremely limited in growth and did not sporulate. They were associated with intensely autofluorescent, necrotic host cells. Mature leaves of each cultivar were more resistant to fungal colonization than seedling leaves. Some colonies in mature leaves of Tifit 23DB were completely encompassed by necrotic cells and did not expand further. No sporulation was noted in mature leaves of 86–8770 or Tift 85DB. Fungal colonies were not successfully established in either nonhost. Thickening of plant cell walls at sites of attempted infection was noted in corn. In peanut, guard cells underneath fungal appressoria became autofluorescent.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026056

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTThree intersterility groups, as well as several stocks which were intersterile with all other stocks, were detected among isolates obtained from North American collections referable to theLaccaria laccatacomplex. Members of these intersterility groups were intersterile with both of the intersterility groups previously identified among tested Swedish isolates referable toL. laccata sensu lato.Genetic divergence was detected between each of the four intersterility groups included in analyses of restriction fragment length polymorphisms of mitochondrial and nuclear ribosomal DNA. Multivariate morphometric analyses, however, only revealed a close correlation between basidioma morphology and intercollection pairing reactions in some cases. The following taxa are recognized from North America based on these studies:L. laccatavar.laccata, L. laccatavar.pallidifolia, L. longipes, L. montana, L. ohiensis(=L. tetraspora) andL. striatula.The tested Swedish material is referable toL. laccatavar.moelleriand, putatively,L. laccatavar.pallidifoliaandL. ohiensis.These studies demonstrate the importance of using a variety of character sets for investigating taxonomic and biological problems in agarics that form ectomycorrhizae.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026057

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTThe morphological development of a glucoamylase-producing strain ofAureobasidium pullulansimmobilized in Ca-alginate was investigated during semicontinuous fermentations in a fluidized-bed reactor. A dense mycelium layer was developed by the fungus on the gel bead surface which gave the beads a“pellet-like”configuration. Varying culture conditions, such as bead, substrate and CaCl2concentrations and aeration rate, had a consistent effect on both enzyme production and morphological development of the“in situ”grown cells. Optimization of the growth conditions appeared to be necessary to prevent fungal overgrowth and to enable the immobilized inoculum to continue a sustained level of glucoamylase production over a great number of transfers.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026058

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTGrowth studies were conducted on isolates ofAcremoniumspp.,Atkinsonella hypoxylon, A. texensis, andBalansia epichloëusing the sugars arabinose, fructose, glucose, sucrose, and xylose. Mycelial development and stromata formation on host plants is suggested to be in part regulated by sugar concentration.Atkinsonella hypoxylonandB. epichloëwere shown to colonize wax droplets, suggesting that these species may gain some energy for stroma formation from the waxy cuticle present superficially on grass plants. Most members of the Balansieae demonstrated colonization of oil droplets and protein hydrolysis capacity, the significance of which is undetermined.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026059

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTFive species ofSeptoriaonCornusare described and illustrated. A key for the identification of these species is provided. Two are found on several host species, while the remaining three are restricted to a single species of dogwood. Differences in theSeptoriaspp. may be correlated with proposed evolution in the genusCornus.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026060

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

ABSTRACTPhysiological studies ofDichotomophthoropsis nymphaearumandSclerotium hydrophilumwere undertaken to determine the growth parameters for these two fungi. Optimum or near-optimum growth ofD. nymphaearumoccurred at temperatures of 25 and 30 C. Optimum temperature for growth of S.hydrophilumwas 30 C, although maximum sclerotial production occurred at 25 C. Both fungi were able to utilize all of the carbon sources tested.Dichotomophthoropsis nymphaearumgave lower mycelial yields on xylose, whileS. hydrophilumgrew poorly on maltose. Both fungi utilized inorganic and organic nitrogen sources, but mycelial yields were lower when ammonium sulphate served as the nitrogen source. Glycine was also a poor nitrogen source forS. hydrophilum.Thiamine was required by both isolates ofD. nymphaearumstudied and by one of the isolates ofS. hydrophilum.Light was not found to be essential for conidium production byD. nymphaearumor for the initiation of sclerotia byS. hydrophilum, although it did affect maturation of these structures. Pairing of six isolates of each fungus in all possible combinations and on several media failed to give evidence of a sexual response or production of a sexual state.

ISSN:0027-5514    

DOI:10.1080/00275514.1991.12026061

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor