摘要:

The meadow nematodePratylenchus pratensishas been isolated from root lesions of narcissus, strawberry, apple, cherry, and raspberry in British Columbia. When apparently freed from associated fungi, this species reduced the growth of potato, carrot, red clover, tomato, spinach, and violet seedlings by 50 to 75%, and oat seedlings by less than 4%. In parallel experiments, the commonly associated fungusCylindrocarpon radicicolaas a pure culture reduced growth by only 6 to 11%. The inhibition of growth by the fungus and nematode as a mixed culture was usually greater than the sum of the reductions as pure cultures.The nematodes were separated from associated fungi by planting segments of infested oat roots in plate cultures of powdered peat moistened with a 0.1% solution of malachite green. When the oats planted in this medium had germinated, the nematodes moved from the root segments through the fungicidal medium into the roots of the oat seedlings. These nematode-infested roots proved to be free from the fungi and bacteria naturally associated with the nematode in field infestations.The adult and all the larval stages ofP.pratensisproved to be capable of entering the roots of oat seedlings.

ISSN:1923-4287    

DOI:10.1139/cjr38c-021

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

"Supreme" and "Prince Albert", representing a Dutchtingitanahybrid and an English iris, are much more susceptible to nematode infestation than "Imperator", a Dutch iris, as judged by the number of nematodes per unit volume of invaded tissue,viz.: 596, 108, and 13 respectively. Infestation in "Prince Albert" tends to be confined to the basal plate. Rapid multiplication of the nematodes within the bulb tissue occurs in "Supreme" and "Prince Albert." On the other hand, little multiplication occurs within "Imperator" bulb tissue.The populations within iris bulb tissue consist largely of young larvae in contrast with a high pre-adult population in narcissi. The low population of the heat-resistant pre-adults accounts for the fact that the nematode population in "Supreme" bulbs can be destroyed by a 60-minute immersion at 110° F., whereas a three-hour immersion is required to destroy the nematodes in narcissi.

ISSN:1923-4287    

DOI:10.1139/cjr38c-022

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

Samples of O.A.C. 21 and Wisconsin 38 barley from two stations were germinated at 56° and 50° F. with 44.5% moisture, and with 44.5 and 42.5% moisture at 53° F. Aliquots were kilned and analyzed after 3, 5, 7, 9, 11 and 13 days. Data for extract, diastatic power, and permanently soluble nitrogen, as percentage of wort solids, were plotted against time. Both varieties responded in almost exactly the same manner to changes in temperature and moisture. Values for O.A.C. 21 were consistently higher, but paired curves, representing samples of both varieties from the same station, became closer with increasing time, owing largely to overmodification of the O.A.C. 21. A real difference in malting quality between these two varieties, greater than the differential effect of malting method on them, is therefore indicated.

ISSN:1923-4287    

DOI:10.1139/cjr38c-023

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

Wheat samples (5 lb.) of 12, 18 and 24% moisture content were stored at 21 °C. for periods varying from 4 to 40 weeks with dosages of carbon tetrachloride from 1 to 20 cc. At 12% moisture content the wheat was not damaged by either storage or carbon tetrachloride. At 18% moisture content, samples with 10 and 20 cc. dosages of carbon tetrachloride were undamaged after 10 weeks' storage except for a slight sour odor which disappeared on drying. After 20 weeks' storage there was definite evidence of damage. Samples of 24% moisture content kept well for 4 weeks without any carbon tetrachloride, but those having the higher dosages were damaged. With longer storage all samples at 24% moisture content, no matter how treated, underwent spoilage.

ISSN:1923-4287    

DOI:10.1139/cjr38c-024

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

Samples of eight barley varieties grown at six widely separated points in Canada were malted in duplicate under standard conditions in laboratory equipment. After six days in the germinator, half of each sample was removed and kilned. The remaining halves were grown two days longer before kilning. The relative positions of the varieties with respect to extract, diastatic power, and permanently soluble nitrogen, were changed by the additional two days' growth, but the changes were generally small by comparison with the spreads between varieties and the greater changes in their relative positions when grown at different stations, ft is concluded that the differential effect of malting method is an appreciable source of error in the interpretation of the results of routine malting tests, but that the limiting factor in studies of the comparative malting qualities of varieties is the differential effect of environment on them.

ISSN:1923-4287    

DOI:10.1139/cjr38c-025

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

The two foot-rot diseases of wheat caused byHelminthosporium sativumP. K. & B. andFusarium culmorumW. G. Sm. were studied in nutrient culture solutions instead of in the usual substrates of soil or sand. The most satisfactory results were obtained by first germinating the grains in a specially designed tray, then securing infection of the young plants by adding inoculum to the tray, after which the seedlings were transplanted to the nutrient culture solution. Infection of the seedlings was distinctly increased when sucrose was added to a nutrient solution infested previous to the time of transplantation. Infection was less satisfactory when the seed was immersed in a spore suspension, dried, and germinated on the tray. Very unsatisfactory infection was secured by adding a spore suspension in water, with or without sugar, to the nutrient solution at the time of transplanting the seedlings. Inoculating the seedlings with a spore suspension by means of a hypodermic needle produced practically no infection. Length of shoot, and particularly the dry and the green weight of the entire plant were reliable quantitative criteria for the evaluation of disease. The first method indicated appears to offer several important advantages in that the degree of infection can be controlled.

ISSN:1923-4287    

DOI:10.1139/cjr38c-026

出版商:NRC Research Press    

年代:1938

数据来源: NRC