摘要:

Mycelial colonies ofPlenodomus melilotiMark.-Let., incitant of brown root rot of legumes, were of similar size whether cultured in the light or in darkness on an agar medium. However, numerous pycnidia were produced only in the light. In the presence of 'active' horseradish peroxidase, beef liver catalase, and polyphenol oxidase enzymes, mycelial growth in comparison to controls was accelerated. Numerous pycnidia were produced in cultures incubated in light or darkness. When horseradish peroxidase and beef liver catalase were denatured by autoclaving, cultures were similar to controls.Aspergillus nigercatalase inhibited mycelial growth and pycnidium production. Association of environmental conditions, peroxidase and catalase enzymes, and pathogenicity is discussed.

ISSN:0008-4026    

DOI:10.1139/b69-069

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

An antiviral principle (AVP) has been isolated from tomato plants systemically infected with tobacco mosaic virus (TMV). This principle when mixed with TMV inoculum, or applied separately to the host before inoculation, markedly reduces the infectivity of the virus. Induction of the principle in tomato begins during the very early stages of virus–host interaction; later, with the development of a high level of AVP, there is a concomitant decline both in the amount of virus in the diseased plant and in the infectivity of the virus which is present. The production of AVP is not accompanied by overt signs of hypersensitivity or necrosis in the susceptible tomato host.

ISSN:0008-4026    

DOI:10.1139/b69-070

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

More rapid growth by red alder than by coastal conifer species may be explained by alder's greater foliage surface per unit foliage weight, greater total foliage area per seedling, and higher photosynthetic rate at high light intensities. Net photosynthetic rates per unit foliage area were similar for red alder and the three conifers up to saturating light intensity for the conifers. Relative weight of photosynthetic and nonphotosynthetic tissue was also similar for the four species. Average maximum photosynthetic rates measured for these conifers are comparable to reported rates for woody broad-leaved species.

ISSN:0008-4026    

DOI:10.1139/b69-071

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

On unstable gravel banks along the Thames River, seeds ofSaponaria officinalisare dormant at maturity but many give rise to seedlings in the spring following production. The effects on seed dormancy of several environmental factors which would be experienced by the seeds during the winter were investigated. All seeds which remained submerged for 2 months or more germinated as soon as they were exposed to air and alternating temperatures in the spring. Scarification by moving gravel only promoted germination when combined with subsequent exposure to winter conditions. Only about half of the seeds which were not inundated germinated the next spring. Soaking, rather than low temperature, was shown to be the more important factor in overcoming seed coat dormancy.

ISSN:0008-4026    

DOI:10.1139/b69-072

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Small but significant amounts of silica occur in all brown algae and green Hydrodictyaceae examined. At least in the hydrodictyaceousPediastrumandTetraëdron, the silica predominates in the cell wall. This silica is largely isotropic, non-crystalline opal with a small amount of α-quartz. Occurrence of silica in brown algae constitutes yet another feature suggesting phylogenetic relationships with the Chrysophycophyta, and the siliceous cell walls of the Hydrodictyaceae facilitate an understanding of both the nature of organic substances present and the process of zoosporogenesis.

ISSN:0008-4026    

DOI:10.1139/b69-073

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

After the breakup of the meiotic tetrads, it is usual in the Compositae for the cells of the previously parietal tapetum to invade the anther loculus and form a Plasmodium ramifying between the young spores. In species of three tribes, Helenieae, Heliantheae, and Ambrosieae, an extratapetal membrane is formed at this time, which totally encloses the tapetum and the spore mass. The extratapetal membrane is resistant to acetolysis, and is considered to be chemically similar to the sporopollenin of the pollen grain exine.

ISSN:0008-4026    

DOI:10.1139/b69-074

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Twenty-one European wheat varieties from the World Wheat Assortment in Prague-Ruzynĕ (Czechoslovakia) that were resistant to leaf rust were tested with Canadian leaf rust races 1, 5, 9, 11, 15, 30, 58, and 126. The patterns of rust reaction and genetic studies on representative varieties suggest that the varieties Belocerkovskaja 198, Bezostaja 1, Mironovskaja 264, Mironovskaja 808, Osetinskaja 3, Rannaja 12, Skorospelka 3b, Fertödi 293, and Sládkovičovo K 1004 have geneLr3, the variety Halle 9H39 has geneLr1, the varieties Erythrospermum 142, 953, and 974 I.Z.R. have genesLr1andLr3, and the variety Etoile de Choisy geneLr16. The other varieties tested (Flevina, Sambo, Stabil, Uhčetice 22/IV, and 22/V) have reactions that are different from any of those of the single gene lines tested. The varieties Weique and Salzmünder Bartweizen were resistant to all races test

ISSN:0008-4026    

DOI:10.1139/b69-075

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Procedures for obtaining axenic tissue cultures ofAbies grandis, Larix occidentalis, Picea abies, Picea engelmanni, Picea pungens, Pinus albicaulis, Pinus contorta, Pinus flexilis, Pinus nigra, Pinus ponderosa, Pseudotsuga menziesii, andThuja plicataare described. All species were cultured on a basal medium containing calcium nitrate, magnesium sulphate, potassium phosphate (monobasic), ammonium sulfate, ferric sulfate, manganese sulfate, glucose, 0.8% Bacto agar, and one of three auxins (indoleacetic acid (IAA), naphthaleneacetic acid (NAA), or 2,4-dichlorophenoxyacetic acid (2,4-D)) at various concentrations. Growth of most species was further enhanced by the addition of several vitamins and amino acids. These species were relatively specific in their auxin requirements. The type of sterilant (H2O2, NaOCl) and manipulation required in the preparatory procedures were also specific for individual species.

ISSN:0008-4026    

DOI:10.1139/b69-076

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Cold-water extractives of grand fir,Abies grandis(Dougl.) Lindl., heartwood yielded pinitol, sequoyitol, and a compound containing a ketone group. No other organic chemicals were extracted.

ISSN:0008-4026    

DOI:10.1139/b69-077

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

One species of Chlorophyceae, one species of Phaeophyceae, and six species of Rhodophyceae, collected in Nova Scotia, are recorded for the first time from North America.

ISSN:0008-4026    

DOI:10.1139/b69-078

出版商:NRC Research Press    

年代:1969

数据来源: NRC