摘要:

A strain of variegated barley that originated in a Saskatchewan field produces, on selfing, progeny of which approximately 90% are albino, the remainder striped or variegated with rare full green exceptions. In crosses, variegated ♂ × green ♀ produced 7 albino, 4 striped, and 11 greenF1plants. The reciprocal cross yielded 1 striped and 41 greenF1plants.F2segregation approximated three green to one of all others (albino and variegated). From someF2andF3progenies it was inferred that two genetic factor pairs might be segregating. On that hypothesis the dominant hypostatic factor for variegation must be very unstable, mutating at a high rate to white. The peculiarities of inheritance may be explained also, however, on the basis of a combination of gene and (maternal) plastid inheritance. On this interpretation the plastids present in the egg affect the colour of the seedling that develops from it. When green plastids or proplastids are present in the egg, many of them, but not necessarily all, are induced to mutate if the whitewgene is homozygous, but fewer if thewgene is heterozygous. If white plastids only are present in the egg it is probable that the seedling will be an albino regardless of gene cont

ISSN:1923-4287    

DOI:10.1139/cjr46c-017

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Investigations of decay inThuja plicataD. Don. in British Columbia have shown that the major heart-rotting fungi of living western red cedar on the Coast, in decreasing order of importance, arePoria asiatica(Pilát) Overh. (brown cubical pocket and butt rot),Poria albipellucidaBaxter (white ring rot),Fomes Pini(Thore) Lloyd (white pitted trunk rot),Meruliussp. (brown crumbly butt rot), andPoria subacida(Peck) Sacc. (spongy white rot). In the Interior of the Province they arePoria asiatica,P.WeiriiMurr. (yellow ring rot),Fomes Pini,Polyporus balsameusPeck (brown cubical butt rot),Meruliussp., andPoria subacida. Other fungi attacking the heartwood of living trees less extensively areFomes annosus(Fr.) Cke.,F.nigrolimitatus(Romell) Egel.,F.pinicola(Sw.) Cke.,Armillaria mellea(Fr.) Quél.,Omphalia campanella(Fr.) Quél.,Polyporus SchweinitziiFr., andConiophora cerebellaPers.On the areas investigated, loss through decay in stands 50 to 450 years of age never exceeded growth increment. It was indicated that decay in younger stands was of importance. Loss through decay and incidence of infection was appreciably higher in the Interior than on the Coast. No reliable external indications of decay in the standing tree were found.Deterioration in felled trees was caused byPoria Weirii,P.albipellucida,P.subacida,Armillaria mellea,Omphalia campanella,Fomes annosus,F.nigrolimitatus, andF.pinicola.Polyporus cuneatus(Murr.) Overh., andHymenochaete tabacina(Sow.) Lév. were the major decay organisms of cedar sapwood and slash.Polyporus abietinus(Dicks.) Fr.,P.versicolor(L.) Fr.,P.semipileatusPeck,P.hirsutus(Wulf.) Fr., andPoria isabellina(Fr.) Overh. were restricted in distribution or of irregular occurrence.To assist in the identification of cultures all the major heart-rotting organisms were grown on tannic and gallic acid media. Seventy-seven species of Basidiomycetes were collected on living and deadThuja plicatain British Columbia from 1943 to 1945.

ISSN:1923-4287    

DOI:10.1139/cjr46c-018

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Guinea-pig adrenals were stained for ascorbic acid. In the normal adrenal, staining was found in both cortex and medulla though with greatest density in the zona fasciculata. The stained scorbutic adrenal showed only a few granules.The mossesMnium cuspidatumandMnium affinecontain ascorbic acid in appreciable amounts. Following staining, fine black granules could be seen in both species. The stain intensity of the granules roughly corresponded to their relative ascorbic acid content.Having satisfactorily established the validity of the staining solution by the above experiments the development of ascorbic acid in the rose hips ofR.aciculariswas followed throughout the summer. There was found to be some association between the ascorbic acid and chloroplasts. With increasing maturity there developed a gradual accumulation of fine granules in the cells of the tissue as well. These granules showed no apparent relationship to any formed elements in the cells. Staining densities roughly parallel ascorbic acid content.

ISSN:1923-4287    

DOI:10.1139/cjr46c-019

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

This work represents a continuation of previous studies by the writer on theFusariumof muskmelon wilt, with a view to determining the extent to which the cultural phenomena noted in this organism are characteristic of other Fusaria. The section Elegans is represented by 13 organisms, and the sections Liseola, Discolor, and Gibbosum by one each. Abnormal areas appearing in cultures of these organisms were investigated from the genetic viewpoint, and the results showed the larger of these to be of mutant origin. Evidence was obtained that the 'sclerotia' that appeared in cultures of some of the organisms may likewise be of mutant origin, but this was not deemed conclusive. A comparison of the properties attributed in the literature to 'sporodochia' appearing in Fusarium cultures with those of the patch mutants studied here indicates that the terms are synonymous in this case, and hence the common practice in Fusarium taxonomy of measuring 'macroconidia from sporodochia' is questioned. Since the wild types of the Fusaria studied were readily displaced in culture by mutants, it is evident that some method of maintaining the original isolates in the pure state is fundamental to a consistent taxonomy of the genus. In this connection the practice of maintaining Fusaria in tubes of sterilized soil is recommended, since experiments showed that this type of cultural treatment does not favour the loss of the wild type. A discussion is given concerning the cause of variation and the extent to which it occurs in nature.

ISSN:1923-4287    

DOI:10.1139/cjr46c-020

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

The conclusions that the 'normal culture' stage described by certain specialists in Fusarium taxonomy represents the dominance of the original or wild type by a mutant, and that the 'sporodochia' that appear in laboratory cultures ofFusariumare actually patch mutants are shown to have an important bearing on the taxonomy of the genus. The indication is that the species descriptions of many Fusaria are based to a large extent on cultural variants of the types found in nature. It is emphasized that in order to avoid confusion, care should be taken to base species descriptions on the characters of the wild types. Further, while morphological separation of wild types may be found extremely difficult within certain groups of Fusaria owing to the close similarity of the components, the effort should not be abandoned because of the wide range of variation displayed by these organisms in artificial culture. Species should be merged only when morphological separation is extremely difficult or where variabilityin naturemakes consistent diagnosis uncertain.

ISSN:1923-4287    

DOI:10.1139/cjr46c-021

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Wheat passing through the Winnipeg market in 1943 and 1945 harboured a large number of micro-organisms. They were not found on all kernels, but were present on all 10-gm. samples. The number was smallest on No. 1 Manitoba Northern red spring wheat and progressively larger on each successive lower grade.The organisms consisted chiefly of two species of bacteria, which persisted on the grain even after repeated vigorous washings. One was identified asBacterium kerbicola aureumDuggeli. The other undoubtedly is a representative of the genusPseudomonas. It is suggested that these species should be considered epiphytic on wheat.

ISSN:1923-4287    

DOI:10.1139/cjr46c-022

出版商:NRC Research Press    

年代:1946

数据来源: NRC