摘要:

Certain seed-borne pathogens are inactivated to a marked degree when infested seed is sown in natural soil.Polyspora liniandColletotrichum lini, the fungi causing respectively the Browning and Anthracnose diseases of flax, are so affected, both when naturally and artificially infested seed is used. This appears to be due largely to the antibiotic action of the micro-organisms of the soil, since in sterilized soil similar seed produces significantly higher percentages of infection. Infection may be reduced as much or more by this means as by seed treatment with certain fungicides.On the contrary, some seed-borne pathogens apparently are not inactivated to such an extent as to produce consistently less disease in natural than in sterilized soil. This has been indicated by preliminary experiments with certain smut fungi, for example those causing bunt of wheat.

ISSN:1923-4287    

DOI:10.1139/cjr38c-033

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

Analyses were made of alfalfa hays cut at six different stages of growth during the course of one growing season. For the determination of the soluble forms of nitrogen encountered in this study, the method developed by Wasteneys and Borsook for the fractional analysis of incomplete protein hydrolysates was applied. This procedure ensured the securing of more definite information concerning the exact gradations of protein synthesis and breakdown than is obtained by the usual amino and amide nitrogen determinations.The data for total nitrogen show a relatively steady decrease with advancing maturity of the harvested material. Also, the second and third cuttings of hay exhibit a distinctly higher total nitrogen content than the first cutting.Total soluble nitrogen tends to exhibit considerable fluctuation throughout the growing period. Cuts made later in the season show a progressive decrease in the proportionate amounts of this fraction. Particularly striking is the finding that, in all cuttings, total soluble nitrogen tends to be present in very large amounts during the early part of flowering.Results obtained from the application of the method of Wasteneys and Borsook make possible the presentation of a relatively clearly defined pictur of protein synthesis and degradation throughout the growing period. These data further strengthen the assumption that the period between bud formation and the commencement of flowering represents a very critical stage in the life history of the plant.

ISSN:1923-4287    

DOI:10.1139/cjr38c-034

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

Certain components of Wildiers' Bios complex, fractionated and concentrated according to the procedure of Miller and co-workers, were found capable of replacing the stimulative action of yeast extract on strains ofRhizobium trifolii, as measured by acid production. Bios I was inactive, while Bios II B, V, and II A possessed definite activity, the potency of the fractions increasing in the order named. Moreover, the ability of these fractions to increase hydrolysis of urea by urease was in direct proportion to the stimulative effect exerted by them on theRhizobia. These effects could not be brought about in synthetic media by the addition of crystalline vitamin B1, nicotinic acid, uracil, choline, β-alanine, carnosine, β-indole acetic and β-indole butyric acids, glutathione, cysteine and vitamin C.

ISSN:1923-4287    

DOI:10.1139/cjr38c-035

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

Studies of sexuality inFomes pinicola(Sw.) Cooke based on material from 43 new sources, combined with results already published (1929) have led to the following conclusions: (i) Collections from North America may be divided into two groups, a large Group A, and a small Group B. Monosporous mycelia of any culture in Group A are compatible (mutually fertile) with those of every other member of the group; similarly monosporous mycelia of any member of Group B are compatible with other monosporous mycelia of Group B; but monosporous mycelia of Group A are almost completely incompatible (sterile) when paired with those of Group B. (ii) Collections of European and Japanese origin form a third Group C. These are almost completely compatible with Group A and only partially incompatible with Group B. (iii) In Group B are several isolates of the so-calledPopulusor hardwood form ofF.pinicolawhich has been designated at times as a separate speciesF.marginatus. The remainder are, however, the typical coniferous or "red-belt" form.

ISSN:1923-4287    

DOI:10.1139/cjr38c-036

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

Determinations of total nitrogen and nitrogen fractions were made on 144 samples of barley representing 12 varieties grown at each of 12 widely separated experimental stations in Canada.A highly significant positive correlation between alcohol-soluble protein nitrogen and total nitrogen was found both within and between varieties. No correlation between total nitrogen and other nitrogen fractions was found between varieties; but significant positive correlations were found within varieties, that for insoluble protein nitrogen being considerably higher than those for total salt-soluble nitrogen, salt-soluble protein nitrogen, and non-protein nitrogen. With increasing total nitrogen, the proportion in salt-soluble form decreases, that in alcohol-soluble form increases, and that in insoluble form remains relatively constant. The results thus offer further support for Bishop's "Protein regularity principle".Mean varietal differences were found with respect to each nitrogen fraction, but elucidation of differences in nitrogen distribution patterns was complicated by the effect of varietal differences in total nitrogen content. Statistical analyses demonstrated the validity of eliminating this effect by adjusting varietal means for fractions to values corresponding to equal total nitrogen contents. When this was done it was found: that the three two-rowed varieties (Charlottetown 80, Hannchen, and Victory) were higher in alcohol-soluble protein nitrogen and lower in insoluble protein nitrogen than any of the six-rowed varieties; and that the four smooth-awned six-rowed varieties (Nobarb, Regal, Velvet, and Wisconsin 38) were lower in total salt-soluble nitrogen and higher in insoluble nitrogen than any of the rough-awned six-rowed varieties (O.A.C. 21, Mensury, Ott. 60, Olli, Peatland, and Pontiac). Owing to the variation between varieties within classes, and the small number of varieties studied, the average differences between the three classes are not statistically significant. Nevertheless, since by comparison with the rough-awned six-rowed varieties, the two-rowed varieties yield higher malt extracts, and the four smooth-awned varieties yield lower malt extracts and are lower in enzymatic activity, the indications of a possible relation between nitrogen distribution and malting quality are interesting.

ISSN:1923-4287    

DOI:10.1139/cjr38c-037

出版商:NRC Research Press    

年代:1938

数据来源: NRC