摘要:

When preparing winter flower-bud material for microscopic examination, unbroken series of sections cannot be obtained by the ordinary methods of dehydrating, imbedding, etc. This is due to the diverse but characteristic structures found in a resting bud. These structures include heavy impervious protective scales, dense mats of hairs between the young leaves, flowers and bracts and a delicate embryonic tissue at the tip. A continuous series of sections may be obtained by (1) making use of extremely sharp tungsten needles to remove the more minute scales and bracts, especially those between the embryonic flowers; (2) soaking the material for at least two months m 70% alcohol; (3) usingn-butyl alcohol instead of absolute alcohol and xylol; (4) keeping the material continuously at low pressures; and (5) using an alcoholic stain. Each of these additional steps helps, but all are necessary for completely satisfactory results. A method by which the special tungsten needles may be made is described. The continuous treatment at low pressures is made possible by using a two ounce bottle fitted with a capillary tube and stopcock The stains which proved most satisfactory were alcoholic solutions of safranin and acid fuchsin.

ISSN:1923-4287    

DOI:10.1139/cjr37c-009

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

Stage of growth at the time of the spring emergence of the Hessian fly appears to account for the differential resistance of varieties of winter wheat at Saanichton, British Columbia. Varieties more advanced in growth appear to be more resistant or freer from infestation than varieties less advanced. There was a positive correlation (r = + 0.84) between the number of days to maturity and infestation, and a negative correlation (r = − 0.63) between the height of the wheat and infestation on April 1, about the time the fly emerges.The varieties of winter wheat grown on the Dominion Experimental Station at Saanichton, B.C. showed culm infestation as follows: (i) Practically free from infestation (0–4%) Dawson's Golden Chaff O. 24, Dawson's Golden Chaff (O.A.C. 61) Kanred × Dawson's Golden Chaff, Kharkov × Dawson's Golden Chaff Imperial Amber, O.A.C. 104, Red Rock and Triplet; (ii) Moderately infested (30–80%) Crail Fife, Forty-fold, Hybrid 128, Hussar, Oro, Yanward, and Yaroslav; (iii) Heavily infested (85–100%) Albit, Golden Sun, Jenkins × Ridit, Kharkov, Marshal Foch, Martin, Ridit, Sun, Victor, White Odessa and Yeoman.Nitrate of soda, superphosphate, and a complete fertilizer broadcast or drilled had no significant effect on Hessian fly damage.

ISSN:1923-4287    

DOI:10.1139/cjr37c-010

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

Four physiologic forms of loose smut of wheat have been found in Manitoba. Two of these forms were collected in the field, one on Reward and the other on Mindum. The two other forms appeared in the course of artificial inoculations in the greenhouse. The origin of physiologic forms of loose smut of wheat is discussed. It is considered that one of the forms that appeared in the course of the greenhouse inoculations may have resulted from a mutation. Evidence is put forward which indicates that different physiologic forms occur in Eastern and Western Canada. None of the 13 varieties of wheat used in the inoculation experiments proved to be resistant to all physiologic forms. The inoculation of Reward, Marquis, Garnet, and Pentad × Marquis with their own spores for four generations did not result in appreciably increasing the infections on these varieties. It was also shown that the healthy Reward plants that are sometimes present in a population grown from artificially inoculated seed are not resistant to loose smut, but have escaped infection because of faulty inoculation.

ISSN:1923-4287    

DOI:10.1139/cjr37c-011

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

Fomes roseusandF.subroseusare heterothallic and bipolar. With one exception, complete interfertility exists between haploid mycelia derived from different sources. The exception is of particular interest since it shows that two cultures ofF.roseusfrom widely separated sources possess one interfertility factor in common.F.roseusandF.subroseusmay be differentiated on the basis of their spore characters. The failure to obtain clamp connections many of the many pairings of a haploid mycelium ofF.roseuswith a haploid mycelium ofF.subroseusonly serves to emphasize that these two fungi are distinct.

ISSN:1923-4287    

DOI:10.1139/cjr37c-012

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

Single virus streak, potato virus X, streak virus X and aucuba mosaic (tobacco virus 6) were found causing diseases of tomatoes in commercial glasshouses in British Columbia during 1936. Single virus streak was the commonest disease although greater losses were caused by streak virus X. Aucuba mosaic was found in one case only, but was highly pathogenic. Potato virus X was present mixed with single virus streak, giving rare cases of mixed virus streak. Tomato mosaic (tobacco virus 1) was not present as a tomato disease.Single virus streak serum did not give a precipitate when mixed with aucuba antigen, thus indicating that the viruses are distinct. However, a slight precipitate with tobacco virus 1 antigen did indicate distant relationship with this form. Although three strains of single virus streak could be distinguished by symptoms produced on tomatoes when inoculated simultaneously, these strains proved to be serologically identical.

ISSN:1923-4287    

DOI:10.1139/cjr37c-013

出版商:NRC Research Press    

年代:1937

数据来源: NRC

摘要:

The bulb and stem nematode,Ditylenchus dipsaci, attacks narcissus, iris, red clover and strawberry in the Pacific Northwest. The isolations from each of these important crops are herein described as strains.Preliminary studies of the transfer of these strains establish the existence of three strains ofD.dipsaciin the Pacific Northwest,viz.:(i) Red clover strain; characterized by causing swollen crowns and stunt in red clover seedlings.(ii) Strawberry strain; characterized by a limited host range, swollen crowns in strawberry seedlings, and entrance into red clover seedlings without visible tissue reactions.(iii) Narcissus and iris strain; characterized by a wide host range and entrance into clover and strawberry seedlings without visible tissue reactions.No satisfactory technique of establishing the host range of the biological strains ofD.dipsacihas been developed. The clamping of glass rings filled with a nematode suspension in moist pulverized peat to the foliage of test plants did not affect the test plants in a constant manner. The examination of seedlings after clarification in a lacto-phenol solution containing acid fuchsin gave more constant results. The seedlings were removed from infested soil shortly after they appeared above ground.The reports of host specificity of the red clover strain were not confirmed, for the red clover strain entered white clover and alfalfa, hitherto considered resistant. Likewise, the reports of host specificity of the narcissus strain were not supported by our experimental results. The narcissus strain entered red clover and oats, also considered resistant hitherto.

ISSN:1923-4287    

DOI:10.1139/cjr37c-014

出版商:NRC Research Press    

年代:1937

数据来源: NRC