摘要:

UsingEuglena gracilisvarbacillarisas the assay organism a study was made of the ability of 21 different bacteria to synthesize vitamin B12. Thirteen of the 21 organisms studied were found to secrete vitamin B12.

ISSN:0008-4026    

DOI:10.1139/b54-046

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Forty-two cultures of wheat stem rust (Puccinia graminisvar.triticiErikss. and Henn.), comprising 34 physiologic races, were subjected to selfing studies each of which involved the inoculation of barberry plants with the sporidia of a race, and the determination of the races in the uredial cultures derived from the aeciospores. In all of the cultures studied, the pathogenic properties expressed on the differential hosts appeared to be inherited according to the same principles. On the varieties Marquis and Kota (Triticum vulgare), pathogenicity of the races in the progeny tended to resemble that of the parent race. On Reliance (T.vulgare), avirulence was a dominant character, virulence a recessive one. On the durum wheats Arnautka, Mindum, and Spelmar, virulence was a dominant and avirulence a recessive character. On Einkorn (T.monococcum) and on Vernal (T.dicoccum), avirulence was dominant to virulence. In the progenies of some races, pathogenic variation occurred though it did not transgress the circumscribed limits of the parent race; the population therefore consisted chiefly of substrains (biotypes) of the same race.

ISSN:0008-4026    

DOI:10.1139/b54-047

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Phosphorylase activity was demonstrated in the chloroplasts of wheat, bean, and sunflower by incubating living starch-free sections with glucose-1-phosphate in acetate buffer at pH 5.8–6.0.

ISSN:0008-4026    

DOI:10.1139/b54-048

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

An anatomical study was made of galls which occur naturally on the stems of boysenberry and Himalaya blackberry plants. The galls form at any region of the stem of the floral canes of plants systemically infected withAgrobacterium rubiand originate from or near the cambial layer, and not from the outer layer of the pericycle. The vascular system in galls caused byA.rubiandA.tumefacienson broad bean, tomato, sugar beet, loganberry, and Himalaya blackberry plants is connected to the vascular system of the organ on which they are growing.

ISSN:0008-4026    

DOI:10.1139/b54-049

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Normal tetraploid alfalfa,Medicago sativa L., is characterized by meiotic irregularities consisting of a low percentage of univalents, trivalents, and quadrivalents. While these irregularities might suggest an autoploid origin, their frequency is too low to be conclusive. Cytological studies of the induced octoploid and of the hexaploid, obtained from crossing tetraploid and octoploid, indicate that the two genomes in the tetraploid are only partially homologous. The partial homology is established by the meiotic behavior in the hexaploid in which a low univalent frequency indicates fairly complete pairing between theAandBgenomes. The comparatively low frequency of quadrivalents in the octoploid indicates a correspondingly low chiasma frequency at pachytene. Nevertheless this quadrivalent frequency in the octoploid is more than three times as high as in the tetraploid which suggests a lack of complete homology between the two genomes. The theory is advanced that tetraploid species ofMedicagooriginated from crosses between a series of diploid species fairly similar cytologically but differing in well marked, morphological characters. This affords an explanation for the inheritance of some characters in a disomic and others in a tetrasomic manner. Cytological and genetic evidence thus points to tetraploid alfalfa as originating as an alloploid from closely related diploid species.

ISSN:0008-4026    

DOI:10.1139/b54-050

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

An ascomycetous fungus, namedCryptoascus graminissp. nov., is described. This fungus is found parasitic on the roots of wheat, oats, and barley in Prince Edward Island.

ISSN:0008-4026    

DOI:10.1139/b54-051

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

The subterranean sclerotia ofPorta cocos(Schw.) Wolf have been known in North America for more than one hundred and fifty years, but sporophores of the fungus are rare. This paper reports the First fruit bodies of this fungus found in Canada. They developed on poplar pulpwood bolts during storage; the history of the logs from the time of cutting up to the finding of the sporophores is recorded.

ISSN:0008-4026    

DOI:10.1139/b54-052

出版商:NRC Research Press    

年代:1954

数据来源: NRC