摘要:

Two Basidiomycetes,Fomes pini(Fr.) Karst. andPeniophora pseudo-piniWeres. & Gibson, and three microfungi (Ascomycetes),Tympanis hypopodiaNyl.,Retinocyclus abietis(Crouan) Groves & Wells, and a member of theCoryne sarcoidescomplex, are the fungi most frequently isolated from the heartwood of living jack pine (Pinus banksianaLamb.) in the Province of Ontario. Of these, onlyF. piniis consistently associated with decayed wood. In laboratory tests all five caused significant weight losses in jack pine heartwood samples, and all but theC. sarcoidescomplex appreciably altered the color of the wood.T. hypopodiawas exceedingly antagonistic towardsF. pini, both in malt agar culture and when inoculated in advance ofF. piniin jack pine wood samples. The activity ofP. pseudo-piniin the test samples was reduced slightly by the prior establishment ofT. hypopodiaand theC. sarcoidescomplex, but was stimulated somewhat by the presence ofR. abietis. The presence of theC. sarcoidescomplex in jack pine samples resulted in a moderate increase in the activity ofF. pini.In some cases competitive interactions among heartwood-inhabiting fungi may partly explain the marked variability in defectiveness frequently observed among individual trees in forest stands.

ISSN:0008-4026    

DOI:10.1139/b66-100

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Two hyphomycetes with similar aleuriospore states are considered. One, with aVerticilliumphialospore state, was validly published asVerticillium chlamydosporiumGoddard;Stemphyliopsis ovorumPetch andDiheterospora heterosporaKamyschko are later synonyms. The other has aPaecilomycesphialospore state and was validly published asDiheterospora catenulataKamyschko. The two species show similarities in cultural habit, morphology, and biological specialization and it is proposed that they be considered under one genus, viz.Diheterospora.

ISSN:0008-4026    

DOI:10.1139/b66-101

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The presence of a larch – black spruce forest on the Tantramar copper swamp in southeastern New Brunswick offered an opportunity for the study of natural mechanisms of copper tolerance of plants. Concentrations of copper occur as high as 7% dry weight of peat. Immobilization of copper in the soil by chelation to naturally occurring organic compounds appears to be the most important factor in preventing uptake of the metal in toxic amounts.

ISSN:0008-4026    

DOI:10.1139/b66-102

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Seedlings of several conifer species were artificially subjected to freezing temperatures. Microscopic examination of sections, taken at intervals after the frost, revealed the way in which frost rings developed. Differentiating tracheids and xylem mother cells were killed by the frost, leaving a permanent band of underlignified and crumpled tracheids inside a band of dead cell tissue. Most of the cambial initials remained alive but developed abnormally into short irregular tracheids. Parenchyma cells proliferated mainly from the xylem ray cells. With subsequent growth, the growing stresses, which had become subnormal because of the collapse of killed cells, were restored. This was accompanied by the reestablishment of the cambium to its normal form.

ISSN:0008-4026    

DOI:10.1139/b66-103

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The development of fructifications inColletotrichum graminicola(Ces.) Wils. is compared with that of otherColletotrichumspecies occurring naturally on graminicolous and non-graminicolous hosts. Two types are distinguished: (a) the pulvinate in which the outer epidermal wall and cuticle are ruptured at the same time by the developing conidiophores, setae, and stromatic tissue, and (b) the hypostromatic in which the outer epidermal wall is penetrated by fine hyphae from the epidermal stroma, the cuticle being ruptured separately by the setae and conidiophores.Colletotrichum graminicolaon a wide range of graminicolous hosts exhibits only the pulvinate type, but otherColletotrichumspecies develop in either way depending on the nature of the substrate and the strain of fungus involved. The generic separation ofC. graminicolafrom other species by this criterion is not accepted.

ISSN:0008-4026    

DOI:10.1139/b66-104

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The American species ofAnemoneL. (sectionEriocephalusHook. f. & Thoms.) with tuberous rootstocks were studied by biosystematic methods.Anemone carolinianaWalt.,A. heterophyllaNutt. ex Torr. & Gray,A. tuberosaRydb., andA. edwardsianaTharp (tentatively) are recognized from North America andA. decapetalaArd.,A. triternataVahl, andA. cicutifoliaJohnst. from South America. Karyotypes of the diploid species (2n = 16),A. heterophylla, A. tuberosa, A. decapetala, andA. triternataare described. They resemble the karyotype ofA. carolinianapublished earlier.Anemone edwardsianaandA. cicutifoliaare also presumed diploid from stomatal and pollen grain studies. A new taxon (2n = 32), of undecided status, was obtained from Chile. North American plants included by authors inA. decapetalaare here referred toA. heterophylla. The North and South American species appear to form two separate groups, the species of each continent being more closely related among themselves than to those of the other continent. Fewer stomata, larger chromosome size, and higher DNA content are characteristic of the North American species. Additional support for the separation of the two groups derives from limited meiotic studies which indicate a larger number of inversion differences in inter- than in intra-continental hybrids.

ISSN:0008-4026    

DOI:10.1139/b66-105

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Five western North American birches,Betula fontinalis,B. glandulosa,B. glandulifera, B. resinifera, andB. papyrifera, are studied taxonomically. Four hybrids,B. ×winteri,B. ×sargentii,B. ×arbuscula, andB. ×uliginosa, are described for the first time and three others,B. ×utahensis,B. ×eastwoodae, andB. ×sandbergii, are also included. Populations formed when species are in contact have been analyzed and the nature of several hybrid entities determined.B. ×uliginosaresults fromB. resinifera×B. glandulifera. In this population, introgression is towardB. glandulifera, which has the higher chromosome number.B. glanduliferaalso hybridizes withB. glandulosaproducingB. ×sargentii. Most gene flow is towardB. glandulifera, which has the higher chromosome number. InB. glandulosa×B. fontinalis(B. ×eastwoodae) introgression was little influenced by environmental selection, the hybrid was as common as either parental species, and any gene flow was in either direction.B. ×utahensisresults fromB. papyrifera×B. fontinalis. Introgression is towardB. papyrifera. Hybridization ofB. ×sargentiiand B.papyriferaproducesB. ×arbuscula, a rare hybrid. Hybridization ofB. resiniferaandB. papyriferaresults inB. ×winteri, with introgression in both directions.B. ×sandbergiiresults fromB. papyrifera×B. glandulifera. Probably as a result of environmental influence in the analysis area, introgression was towardB. glandulifera, with the lower chromosome number.

ISSN:0008-4026    

DOI:10.1139/b66-106

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The dry twist system of culturing rust from a single urediospore or aeciospore provides a simple, rapid, and straightforward procedure which requires a minimum of manual dexterity. Two successive crops of urediospores, the first used to infect differential varieties for race identification, and the second crop for collection of a pure increase of the culture, can be produced directly from the single spore.The system combines three separate techniques: isolation of single spores from dialysis tubing cellophane; inoculation of single spores by the dry twist method, which involves drawing the needle tip lightly up along the dry leaf blade with a twisting motion; and the subsequent development of infection, first on the attached leaf and then on the excised leaf blade floating on benzimidazole in a closed petri dish. Dry twist is recommended for general use in the isolation, purification, and increase of rust cultures.

ISSN:0008-4026    

DOI:10.1139/b66-107

出版商:NRC Research Press    

年代:1966

数据来源: NRC

ISSN:0008-4026    

DOI:10.1139/b66-108

出版商:NRC Research Press    

年代:1966

数据来源: NRC