摘要:

The ascorbic acid content in the leaves of 10 wild plants that grow in New Brunswick was determined at approximately two-week intervals from June to September. 'Free' and 'total' dehydroascorbic acid were measured, using the method of Roe. The total ascorbic acid is highest in young green leaves. After the plants have flowered the ascorbic acid decreases. It becomes almost negligible when the leaves have wilted and turned brown. 'Free' dehydroascorbic acid was present in all 10 plants in small quantity. It fluctuated from time to time but remained fairly constant for all the plants during the period of investigation, and was independent of the 'total' value for that plant. The values for ascorbic acid have been measured for ripe strawberries, for fiddleheads, and for several common vegetables over the same summer months. They have been tabulated for comparison with the values of ascorbic acid of the 10 wild plants.

ISSN:1923-4287    

DOI:10.1139/cjr47c-009

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

Investigations on the transmission of the Dutch elm disease were carried out during summer of 1946 in Canada, where the only known vector of the fungus is the native bark beetle,Hylurgopinus rufipes. By close observations of young elms, recently and naturally infected withCeratostomella Ulmi, it was found that by boring tunnels through the thin bark of twigs or small branches to the cambium, the adults of this beetle can inoculate the disease to healthy trees.

ISSN:1923-4287    

DOI:10.1139/cjr47c-010

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

A study of the species ofEntylomaon North American composites suggests that almost every form can be assigned to one of two phyletic groups.E.polysporumcontains most of the forms with densely crowded, rather large teliospores and no conidia.E.DavisiionRudbeckia hirtaand, probably, a fungus onLepachys columnarisare segregated from it.E.Compositarumcontains most of the forms with smaller, uncrowded spores and abundant conidia.E.arnicaleand possibly one or two other forms may be regarded as segregates from this species.Emended descriptions ofE.polysporumandE.Compositarumare given to clarify the differences between these two species. Corrections are also made in the identification of some exsiccati specimens.Comparisons are made with European forms to the extent that material has been available, but far more study of European specimens is needed to allow assessment of some species.Species concepts for these fungi are discussed, and criteria are suggested for adequate morphological studies.

ISSN:1923-4287    

DOI:10.1139/cjr47c-011

出版商:NRC Research Press    

年代:1947

数据来源: NRC