摘要:

Cholesterol and related sterols were found to stimulate the sexual reaction between compatible strains of heterothallicPythiumspecies but were not essential to the mating process. The sterols induced the formation of antheridia, oogonia, and mature oospores in reportedly unisexual strains ofP. catenulatumandP. sylvaticumbut did not affect their corresponding compatible strains.

ISSN:0008-4026    

DOI:10.1139/b71-055

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Soluble proteins extracted fromPhaseolus vulgarisprimary leaves infected withAgrobacterium tumefacienswere separated by disc electrophoresis and stained with Coomassie blue. Wounded but noninfected healthy leaves were used as a control. Gel scans revealed little difference in protein profiles between healthy and tumored leaves. Peroxidase isoenzymes were visualized on the gels with benzidine dihydrochloride – H2O2. Distinct differences were found in the number and activity of peroxidase bands between extracts. Extracts from tumored leaves contained more intensely stained peroxidase isoenzymes than healthy leaves. Leaves that were inoculated with a non-tumor-producing strain ofA. tumefacienshad essentially the same protein and peroxidase profile as the healthy leaves.

ISSN:0008-4026    

DOI:10.1139/b71-056

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Growth of three snow mold fungi,Typhula idahoensisRemsb.,T. incarnataLasch ex Fr., andT. trifoliiRostr., was studied in agar and liquid culture.T. idahoensiswas grown successfully in shake culture and its respiratory physiology investigated; some of the attendant problems are discussed.All three fungi were highly psychrophilic. The optimum temperatures for growth were 5–10 °C, the maximum about 20 °C and the minimum around −5 °C. Sclerotia were produced at all temperatures which permitted growth, but most abundantly at temperatures above 10 °C.Cultures grown at 10 °C ceased to grow on transfer to temperatures above 20 °C but, within limits, growth resumed on return to 10 °C after a lag period approximately proportional to the degree and duration of the temperature elevation.Oxygen uptake byT. idahoensiswas optimal at 20 °C, about 15 °C higher than the optimum growth temperature.Respiratory quotients tended to be higher at 20 °C than at 5 °C and after starvation of the mycelium increased to a greater degree at 20 °C on addition of glucose or acetate. Starvation of the mycelium effectively reduced the level of endogenous reserves.The fungus was able to use, to differing degrees, a variety of hexose and pentose sugars as respiratory substrates. The percentage stimulation of the oxygen uptake by these sugars was greater at 20 °C than at 5 °C.

ISSN:0008-4026    

DOI:10.1139/b71-057

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Lodgepole pines were inoculated in groups of 100 trees withEurophium clavigerumat monthly intervals between May and October. The number of trees showing a fully resistant response to this inoculation reached a maximum in early July and then gradually declined. When resistant lodgepole pine trees were inoculated at intervals of 6 ft up the stem, the extent of the resistant response was at a maximum in the lower 20 ft of the stem.Des Pins de Murray furent, par groupes de 100, inoculés d'Europhium clavigerumchaque mois entre mai et octobre. Le nombre d'arbres présentant une résistance absolue à cette inoculation atteignit un maximum au début de juillet, puis décrut progressivement.La réaction de résistance était maximale dans les 20 pieds de base chez les sujets résistants inoculés à tous les 6 pieds le long de leurs tiges.

ISSN:0008-4026    

DOI:10.1139/b71-058

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Four random clones of American sycamore supplied with four concentrations of Hoagland's solution differed in their response to and interacted with treatment as far as height and diameter growth and total dry matter production in the first growing season were concerned. Varying nutrient intensity did not affect the time of the seasonal peak of height and diameter growth; better growth was maintained subsequent to the seasonal peak at the higher concentrations, however. The proportions of the trees in terms of dry-matter distribution and branching characteristics changed with nutrient concentration.

ISSN:0008-4026    

DOI:10.1139/b71-059

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Zoosporic fungi, mainly Chytridiales, are recorded from 61 sites in 10 different Base Camp Lowland habitats. Of the eight genera and 19 species recoveredCatenophlyctis(Phlyctorhiza)variabilis, Hyphochytrium catenoides, Nowakowskiella elegans, Olpidium pendulum, Rhizophydium pollinis-pini, R. sphaerotheca, Rhizophydiumsp. (utricularae?), andPythium irregularaehave been reported from the Arctic before.Chytriomyces annulatus, C. poculatus, Nowakowskiella macrospora, N. ramosa, Rhizidium verrucosum, Rhizophydium angulosum, R. coronum, R. eleyensis, R. karlingii, Rhizophydiumsp. (nodulosum?), andRhizophydiumsp. (patellarium?) are reported for the first time from the Arctic.

ISSN:0008-4026    

DOI:10.1139/b71-060

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Two types of surface markings on the aeciospores of five pine stem rusts occurring in Canada were observed under a scanning electron microscope. Spores of four species,Endocronartium harknessii(J. P. Moore) Y. Hiratsuka (=Peridermium harknessiiJ. P. Moore),Cronartium coleosporioidesArth. (=P. stalactiformeArth. & Kern),C. comptoniaeArth., andC. ribicolaJ. C. Fisch., had annulated processes with five to seven layers and each spore had a smooth area. The smooth area was at the same level as the top layer of the processes. Each species could be distinguished by the shape and size of its processes. Spores ofCronartium comandraePk. had no smooth areas and had obtuse or cuspidate processes with no annulations. Different ontogenies were apparent for the two types of spore surface markings.

ISSN:0008-4026    

DOI:10.1139/b71-061

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Seven days after inoculation withEurophium clavigerum(Robinson and Davidson), lodgepole pine seedlings showed an external flow of oleoresin. On the sapwood surface, a white streak extended above and below the wound. The sapwood adjacent to the inoculation was gradually impregnated with resinous compounds, and the bark adhered to the sapwood around this zone of resin-soaking. After 21 days, callus tissue had developed around the margin of the resinous area, and 1 year later, the xylem and the phloem had begun to overgrow the resinous area.The terpenes identified in 60-day-old resinous response from both seedlings and mature trees were β-phellandrene, 3-carene, α-pinene, camphene, β-pinene, myrcene, limonene, andp-cymene. The phenolic substances present in each were pinosylvin, pinosylvin monomethylether, pinobanksin, and pinocembrin.

ISSN:0008-4026    

DOI:10.1139/b71-062

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Cultural characters, spore morphology, and size indicated that a fungus consistently associated with culm and inflorescence lesions on the native fescuesFestuca scabrellaTorr.,F. idahoensisElmer, andF. ovinaL. in Western Canada and northwestern United States wasPhleospora idahoensisSprague. The fungus was morphologically and culturally identical withP. idahoensis, which recently caused severe out-breaks of a stem eyespot disease in crops of the introduced creeping red fescue,F. rubraL. subsp.rubra, in northern Alberta and on the ‘Olds’ cultivar in central Alberta. The widespread occurrence ofP. idahoensisin Western Canada and northwestern Great Plains suggests that it is endemic. The epidemiological implications for crops of introduced fescues of the occurrence of the pathogen on native species are considered.

ISSN:0008-4026    

DOI:10.1139/b71-063

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Examination of the fine structure of the haustorium ofUromyces appendiculatusinPhaseolus vulgarisrevealed a hitherto undescribed structure, the neckband, a short zone of darkly staining deposit in the stem of the haustorium. This occurs above that part of the wall of the stem which is associated with the sheath around the base of the haustorium and below the wall of two distinct layers belonging to the body of the haustorium.

ISSN:0008-4026    

DOI:10.1139/b71-064

出版商:NRC Research Press    

年代:1971

数据来源: NRC