摘要:

Quantitative determinations of extractable gibberellin-like substances (GA's) were made from various organs ofTulipa GesnerianaL. cv. 'Elmus' during cooling and forcing. The barley half-seed and dwarf pea bioassays were used to determine the activity. Shoot tissue contained the greatest levels of GA activity followed by scale and then root tissue. Further division of the shoot and scale tissues showed that the developing flower and bulblets contained the majority of the GA's in these tissues. Quantitative and also qualitative changes, as assessed by chromatogram comparisons, occurred in GA's during the cooling and forcing treatments. The exact pattern of changes within each organ was dependent on the bioassay used. Shoot tissue appeared to be the most sensitive organ to changes in temperature.

ISSN:0008-4026    

DOI:10.1139/b72-112

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Forty-two species of the generaCladoniaandBaeomycesin the lichen family Cladoniaceae are reported from a 13 400 km2area in the mountains and foothills of southwestern Alberta. Thirteen of the species are new to Alberta. The distribution and habitats occupied by each of the species are described. The following North American distribution elements are represented: Arctic–Boreal, 48%; Boreal, 26%; Arctic–Alpine, 10%; Temperate, 5%; Arctic–Temperate, 5%; Boreal–Temperate, 2%,; Temperate–Tropic, 2%; and Pan North American, 2%. Only one of the species is endemic to North America.

ISSN:0008-4026    

DOI:10.1139/b72-113

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

This paper describes the phenetic taximetrics of the 'main groups' of the tribe Arundinelleae (Gramineae) on the basis of 106 characters. At the higher levels of classification the loudetioid, tristachyoid, and danthoniopsoid groups are recognizable in a general way, though the tristachyoids are split intoTristachya, sens. str., and others, in which caseTristachyaallies with loudetioids. Another somewhat miscellaneous group, consisting of certainLoudetiopsis, sens. lat., and some tristachyoid monotypics, is frequently observable. At the more detailed level of classificationLoudetiasectionLoudetiasubsectionsTypicaeandDensispicaemay be generally identified as mayTristachya, sens. str., andDanthoniopsis, sens. str. The genusLoudetiopsis, sens, lat., is strongly fragmented and certain monotypic genera,Gilgiochloa, Muantijamvella, andRattraya, are shown to be moderately isolated. This paper strongly clarifies the tentative groupings provided in an earlier paper (Phipps 1970) based on a systematic sample of half the tribe.

ISSN:0008-4026    

DOI:10.1139/b72-114

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

When seedlings of leafy spurge (Euphorbia esulaL.) were grown at a low nitrogen level (10.5 ppm) the growth of the lateral buds on the shoot was completely arrested by apical dominance while the buds on the roots, although also inhibited, showed considerably greater activity. At a higher nitrogen level (210 ppm) apical dominance was markedly reduced but the resulting outgrowth of the lateral buds increased the inhibiting capacity of the shoot, limiting root bud response. When the main shoot was decapitated the degree to which root bud growth was suppressed by a given number of lateral shoots was inversely related to the nitrogen supply. Inhibition of the root buds by the lateral shoots could be significantly reduced by growing the plants initially at a low nitrogen level so that growth of the lateral buds was arrested. A subsequent increase in the nitrogen supply strongly promoted the growth of the roots buds, some of which were sufficiently released from inhibition to emerge as leafy shoots.

ISSN:0008-4026    

DOI:10.1139/b72-115

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The genusCoprotusis a segregate of the coprophilous genusAscophanusBoud. characterized by minute, translucent, white to yellow apothecia, operculate, non-amyloid, eight- to multi-spored asci, and hyaline, smooth, thin-walled ascospores that contain gas bubbles. Species are distinguished by (1) the number of spores per ascus, (2) the presence or absence of pigments in paraphyses and excipular cells, and (3) the relative size and shape of asci, spores, and sterile elements. Five new combinations are made and six new species are proposed. Keys, descriptions and illustrations are provided for the 18 recognized North American species.

ISSN:0008-4026    

DOI:10.1139/b72-116

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Explanted tissues of cauliflower, carrot, potato, and lettuce have been grown in media containing Zn, Cu, Hg, and Pb. Toxicity levels have been established for each of these elements and a considerable uniformity was noted. Lettuce tissue responds occasionally to high levels of Zn by making extraordinarily prolific growth, a matter that has yet to be explained.

ISSN:0008-4026    

DOI:10.1139/b72-117

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Peroxidase activity has been localized in the cell walls and cytoplasm of wound vessel elements ofColeuswhich had been fixed in glutaraldehyde, incubated in diaminobenzidine (DAB) and H2O2, and postfixed in OSO4. Electron microscopic investigations revealed prominent staining in the reticulate secondary wall and in the primary wall where the secondary thickenings attach. The stain in the secondary wall is finely textured and heavier towards its periphery than towards its core. The staining of the primary wall, however, is coarsely granular. In the cytoplasm of differentiating vessel elements electron-opaque deposits are observed in the plasmalemma, especially where it overlies the secondary thickening, and in the dictyosomes and their associated vesicles. Staining also occurs on the internal membranes of developing chloroplasts where it is most likely the result of photooxidation of DAB.Staining, except in chloroplasts, appears to be due specifically to peroxidase, since either removal of H2O2or preincubation with KCN markedly reduces staining, whereas preincubation with aminotriazole, an inhibitor of catalase, does not. The similarity of localization of peroxidase and lignin in the walls ofColeuswound vessel elements supports the postulate that the enzyme participates in lignification.

ISSN:0008-4026    

DOI:10.1139/b72-118

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Six successive crops of mature conidia were produced at 5 °C by sclerotia ofBotrytis convolutawhen each sporulation was preceded by a 24-h exposure to near-ultraviolet (n.uv.) radiation. Conidial production during these sporulations was greatest during the second sporulation while the largest number of conidia produced per unit of weight lost during the sporulations occurred during the third sporulation. Sporulation began to decline after the dry weight of the sclerotia had fallen to 32% of its initial level.The improved sporulation that occurred during the second sporulation was more marked at 10 °C than at any other temperature tested. It resulted in a shift in the optimum temperature for sporulation from 5 °C during the first sporulation to 10 °C during the second sporulation.At 5 °C, sclerotia were able to produce at least four crops of conidia after only a single, initial 24-h exposure to n.uv. radiation. The total number of spores produced during these sporulations was 11% below that of sclerotia exposed to n.uv. radiation before each of the four sporulations. When sclerotia were placed at 25 °C for the first sporulation, however, they did not sporulate again at either 5 °C or 25 °C without additional exposure to n.uv. radiation.When conidia and conidiophores of one sporulation were left intact on the sclerotia, they did not produce further crops of conidia under otherwise favorable conditions. The suppression of repeated sporulation was lifted by the removal of the conidia. Removal of the conidiophores as well as the conidia did not further influence the number of conidia produced during the subsequent resporulation.

ISSN:0008-4026    

DOI:10.1139/b72-119

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Indices of atmospheric purity (IAP) of 42 sites located in all directions from the aluminum factory at Arvida and spread out in about 250-km2area, were determined on the basis of phytosociology of epiphytes ofPopulus balsamifera. These index values ranging from 0 to 103 were arranged into six groups and the investigated area was accordingly delineated into six IAP zones to represent areas with different levels of fluoride pollution. A relative picture of the approximate limits of fluoride contamination in different zones is obtained by the fluoride accumulation inParmelia sulcatathalli transplanted at various sites in the area.

ISSN:0008-4026    

DOI:10.1139/b72-120

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Warcupia terrestrisgen. et sp. nov. is described from soil from Victoria, British Columbia, Canada. The ascocarp is a globose, brown cleistothecium. The asci are unitunicate, eight-spored, cylindrical to broadly clavate, and deliquesce slowly. The ascospores are smooth, hyaline, ellipsoid, two- or three-guttulate, and lack a germ pore. Paraphyses are present during development and at maturity. There is no conidial state.The ascocarp is initiated by a coiled hypha that becomes a multicelled ascogonium. This is soon surrounded by sterile hyphae that form the wall of the developing ascocarp. In section, paraphyses with free apices are evident at a very early stage of development. Young asci appear shortly thereafter and arise from the entire inner wall of the ascocarp. At maturity the centrum contains a mass of spores, paraphyses, and deliquescing asci.

ISSN:0008-4026    

DOI:10.1139/b72-121

出版商:NRC Research Press    

年代:1972

数据来源: NRC