摘要:

Penicillium repensC. & E. is transferred to the genusPhialocephalaKendrick, and is redescribed and illustrated from the type, another authenticated collection, and a recent collection and isolation.

ISSN:0008-4026    

DOI:10.1139/b63-048

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The significance ofEuphorbia esulaL. as a weed is related to its capacity to persist under adverse conditions and to its mode of reproduction. In both these properties, the root system plays an important role. The root system is initially established by seedlings. The seedling has a vigorous primary root with extensive longitudinal growth and considerable cambial activity. Such a root has been designated a "long" root. By contrast, the first lateral roots produced on the primary root have limited growth and no cambial activity. These roots have been termed "short" roots. Thus, the seedling exhibits a "heterorhizic" pattern. Lateral long roots also arise on the primary root of seedlings but their origin is delayed until cambial activity has begun. Such lateral long roots arise much earlier on seedlings growing in denuded areas than on those growing in areas covered by dense vegetation. The mature root system is described in terms of horizontal and vertical long roots, which make up the conspicuous framework of the system, and of the short roots which they produce. Long roots produce shoot-buds and the origin of these structures is delayed until cambial activity has started. Short roots do not give rise to shoot-buds. Cambial activity in long roots appears to be connected with bud production and its absence in short roots probably underlies their inability to produce buds.L'importance deEuphorbia esulaL. comme mauvaise herbe est connexé a son capacité de persister dans les situations hostiles et à sa methode de reproduction. Dans ces deux caractéristiques, le système des racines a une signification profunde. Initialement le système des racines s'établit dans le semis. Le semis a une racine primaire très forte avec beaucoup de croissance longitudinale et avec une activité considérable du cambium. Une racine de cette espèce s'appelle une "longue" racine (long root). Par contre, les premières racines latérales que poussent sur la racine primaire ont croissance limité et aucun activité du cambium. Ces racines s'appellent les "courtes" racines (short roots). De cette façon, le semis montre un dessin "heterorhizique" (heterorhizic). Les longues racines latérales ont aussi leur origine sur la racine primaire du semis, mais l'origine est retardé jusqu'au commencement de l'activité du cambium. Les racines de cette espèce apparaissent beaucoup plus tôt sur les semis qui sont situés en terre sans autre végétation, que sur ceux qui sont situés au milieu des autres plantes. Le système adulte des racines se décrit sous forme des longues racines de l'espèce horizontale et verticale, lesquelles constituent la charpente bien visible du système, et des courtes racines que sont produites par les longues racines. Les longues racines produisent les bourgeons, mais l'origine des bourgeons est retardé jusqu'au commencement de l'activité du cambium dans les racines. Les courtes racines ne produisent pas les bourgeons. Il paraît que l'activité du cambium dans les longues racines soit corrélative avec l'initiation des bourgeons et l'absence du cambium dans les courtes racines explique probablement leur incapacité à produire les bourgeons.

ISSN:0008-4026    

DOI:10.1139/b63-049

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The author has studied the ecology and phytosociology of cryptogamic epiphytes in southern Quebec. A great number of microquadrats were made on roadside trees and in various forest associations. Many trees were studied from the base to the upper part of the trunk. Thirty-one epiphytic societies or unions of bryophytes and lichens are described. The horizontal and vertical distribution of the unions on sample trees are illustrated.

ISSN:0008-4026    

DOI:10.1139/b63-050

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Carpophores ofAmanita muscaria(Fr.) S. F. Gray collected near Saskatoon, Saskatchewan, contained a mixture of orange-red, water-soluble pigments, none of which was identical with muscarufin, the red pigment reported in mushrooms of this species found in Europe. The main substances accompanying the pigments in the aqueous ethanolic extract were identified and the amounts of each estimated. Of these, fumaric and malic acids, glucose, trehalose, and mannitol have been reported in European specimens of the fungus. Gluconic and citric acids have not previously been described from this species. The composition of the lipid and free amino acid reserves was also determined.

ISSN:0008-4026    

DOI:10.1139/b63-051

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Ten loci were included in linkage studies withHypomyces solanif.cucurbitaeand the following linkage relationships were recognized: (1) compatibility locus (A/a) to a locus for tolerance to the chlorinated nitrobenzenes (cnb-2); (2) locus for femaleness (c) to the locus for maleness (m); and (3) locus for perithecial color (w) to a locus modifying femaleness (stp-4:). Usually parental ditype and tetratype asci were obtained from the cross ♂ × ♀ but the non-parental ditype ascus was found once. The two loci for sex appear to be separated by the centromere to which they both show close linkage. Centromere linkages have also been detected for the compatibility locus and the locus controlling perithecial co

ISSN:0008-4026    

DOI:10.1139/b63-052

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The life cycle ofPrasiola meridionalisis diplohaplontic, consisting of an alternation between morphologically dissimilar sporophytic and gametophytic generations. Mature diploid cells at the apex of the thallus divide meiotically, each producing four haploid cells. Eight pairs of chromosomes were counted at first meiotic prophase. The haploid cells divide mitotically, forming polystromatic, gametophytic tissue which becomes a continuation of the monostromatic, sporophytic, or somatic tissue within the same thallus. Patches of dark green cells, containing potential macrogametes, alternate with patches of very light green color which produce microgametes, forming a mosaic pattern in the gametophytic tissue at the apex of the thallus. Oogamy exists in this species, the spherical macrogamete possessing no flagella. Two or more smaller biflagellate microgametes may approach one macrogamete, but only one unites with it to form the zygote.P. meridionalisreproduces asexually by aplanospores which are formed within the diploid somatic tissue. The new thalli resulting from the germination of aplanospores are morphologically similar to those produced from the zygotes.Cultures ofP. meridionalisthalli grow well in modified Provasoli's medium, when maintained at temperatures of 5–8 °C and provided with alternate light and dark periods. Gametes are liberated only when fruiting thalli are first illuminated for 2 hours with fluorescent tubes and then kept in the dark for several hours at temperatures of 3–5 °C.

ISSN:0008-4026    

DOI:10.1139/b63-053

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

A celery-infecting strain of aster-yellows virus was transmitted byEndria inimica(Say) from Vantage barley to Vantage barley and Ramsey durum wheat. With 8-hour acquisition feeds, an average of 12.4% of the insects became infective. Maximum infectivity, approximately 30%, was reached with 24-hour feeds and no further increase was recorded with longer periods of up to 7 days. The minimum latent period of the virus in the insect was between 18 and 25 days while the maximum period recorded was between 73 and 81 days.

ISSN:0008-4026    

DOI:10.1139/b63-054

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The effect of various temperature combinations on the mating reaction inChlamydomonas eugametoswas determined. Over 90% pairing was observed when mating types were suspended in ammonium nitrate deficient medium in the light at 30 °C for 12 hours and then immediately stored in darkness at 22 °C. Up to 60% pairing has been obtained using other temperature combinations, but the best results were always with the broader temperature shift. Darkness was not essential, but arrested the reaction at pairing and introduced uniformity to the results. The 30 °C−22 °C light–dark shift was shown to be optimal both when mating types were mixed during ammonium nitrate starvation and when held separate during starvation.

ISSN:0008-4026    

DOI:10.1139/b63-055

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

An acidic growth-promoting substance, active in theAvenacoleoptile elongation test, was extracted from Resistant Havana 211 cultivar ofNicotiana tabacumL. This substance cochromatographed with indoleacetic acid (IAA) in three different solvent systems used singly, or in combination in two-direction chromatography. Its concentration–activity curve was also identical with that of IAA.Refinements in the purification procedure and the use of N,N-dimethylaminocinnamaldehyde as a spray reagent for the tobacco leaf extracts have made it possible to obtain a typical IAA color reaction at theRfvalue of the tobacco growth-promoting substance. These results led to the conclusion that the auxin extracted from the tobacco tissues was IAA.

ISSN:0008-4026    

DOI:10.1139/b63-056

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Simultaneous measurements of minute electrical current and water flow through single living cells ofNitella translucenshave shown that there is an electro-osmotic transport of the order of 100 moles of water per Faraday in the direction of the positive ion flow. This implies the existence of water-filled charged pores through the plasmalemma and tonoplast of theNitellacell. The pores available for ion movement are far too few to account for the high water permeability of the cell membranes, and the possible extra turgor pressures which might be produced by an electro-osmotic flow through these pores could not be more than 10−4atmosphere.

ISSN:0008-4026    

DOI:10.1139/b63-057

出版商:NRC Research Press    

年代:1963

数据来源: NRC