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1. |
THREE STRAINS OF CUCUMBER MOSAIC OCCURRING ON TOBACCO IN ONTARIO AND QUEBEC |
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Canadian Journal of Research,
Volume 20c,
Issue 6,
1942,
Page 329-335
J. H. H. Phillips,
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摘要:
Cucumber mosaic was found affecting tobacco plantings in both Ontario and Quebec. From diseased material collected in these regions three strains were isolated and designated as Strains 1, 2, and 3. Strain 1 most closely resembled typical cucumber mosaic in its symptoms on tobacco and tomato. Strain 3 produced a similar type of mottle to Strain 1, but was generally more severe and consistently produced severe leaf narrowing on tomato. Strain 2 was easily recognized by its ability to produce necrotic rings on the inoculated leaves of burley tobacco varieties and the tendency of affected plants to recover from the initial symptoms. The three strains retained their identity through a large number of serial inoculations.Investigations demonstrated that a severe type of streak was produced when tomato plants were inoculated with a combination of cucumber mosaic virus (Strain 3) and potato X virus.Unlike tobacco mosaic virus, the virus of cucumber mosaic was unable to survive over winter in plant tissue in the soil. Field observations indicated that dissemination of cucumber mosaic in tobacco plantings was effected by insect vectors.
ISSN:1923-4287
DOI:10.1139/cjr42c-030
出版商:NRC Research Press
年代:1942
数据来源: NRC
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2. |
THE BEHAVIOUR OF RESAZURIN IN MILK |
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Canadian Journal of Research,
Volume 20c,
Issue 6,
1942,
Page 336-346
C. K. Johns,
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PDF (570KB)
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摘要:
The view that resazurin is not a satisfactory substitute for methylene blue in assessing the hygienic quality of milk has been examined.Resazurin is equally as sensitive as methylene blue to the metabolic activities of bacteria in milk. It is decidedly more sensitive to the presence of non-bacterial factors in abnormal milks (mastitis, late lactation, etc.) and therefore furnishes a more comprehensive index of the true quality of the milk.Potentiometric studies with a wide variety of milks have failed to support the view that resazurin exerts such a strong poising action in market milks as to complicate the test or interfere with the interpretation of results. No evidence was obtained in support of the claim that differences in poising properties of different milks are of sufficient magnitude to affect the results of the test.
ISSN:1923-4287
DOI:10.1139/cjr42c-031
出版商:NRC Research Press
年代:1942
数据来源: NRC
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