摘要:

Water potentials for optimum growth varied with temperature and with the material used to alter water potential. On prune extract – lactose – yeast extract (PLY) agar adjusted with KCl, sucrose, NaCl, or polyethylene glycol (PEG) 8000, growth rates were optimal at 20 or 25 °C and at water potentials of −5 to −10 bars (1 bar = 100 kPa). At 30 °C growth rates were optimal at −35 to −45 bars in the presence of KCl or sucrose and at −10 to −20 bars with NaCl or PEG 8000. Radial growth rates in dried onion leaves, adjusted to various water potentials over salt solutions in sealed chambers, corresponded to those on PLY media adjusted to the same water potentials with KCl or sucrose. Growth was halted at water potentials below −95 to −100 bars in onion leaves or in PLY agar containing KCl or sucrose osmotica, but it was halted at −50 to −60 bars in the presence of NaCl or PEG 8000. Growth ofBotrytis alliiin onion bulb tissue was optimal at 20 °C. Extent of bulb colonization increased linearly with the logarithm of increasing inoculum concentrations applied to small wounds in bulbs. Survival ofB.alliiin dead leaf tissue declined rapidly after 3 and 9 days at 37 and 32 °C, respectively.

ISSN:0008-4026    

DOI:10.1139/b84-209

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Quercus rubraseedlings were grown in a greenhouse in media inoculated with and without vegetative hyphae of the ectomycorrhizal fungiPisolithus tinctorius,Cenococcum geophilum,Scleroderma auranteum, andRhizopogon nigrescens. Some seedlings were also inoculated with basidiospores ofP.tinctoriusandS.auranteumin the greenhouse.Rhizopogon nigrescensdid not infect the seedlings during greenhouse production. Seedlings were planted and grown for two seasons on clear-cut and strip-mine sites. Some nonmycorrhizal seedlings were inoculated with basidiospores at planting. Seedling growth after one season on the clear-cut site was positive for allP.tinctorius,C.geophilum, and vegetativeS.auranteuminoculations and significant differences in growth occurred among inoculation treatments. Root-core samples after one season showed that 80–100% of the seedlings on the clear-cut site had fungal persistence of assigned fungal species from all fungal inoculations except that no ectomycorrhizae were evident with seedlings field inoculated with basidiospores. Growth after two seasons on the clear-cut site was significantly different among treatments but not significantly different on the strip-mine site. Excavated root systems after two seasons showed that 0–100% of the seedlings on the clear-cut and strip-mine sites had fungal retention of assigned fungal species and ectomycorrhizae from basidiospore chip inoculations.

ISSN:0008-4026    

DOI:10.1139/b84-210

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

RootedEuphorbia pulcherrhima(poinsettia) plants, mycorrhizal withGlomus fasciculatumor nonmycorrhizal, were grown in a potting medium with a phosphorus (P) level of 5 μg/g, containingPythium ultimumat 0, 38, 66, or 132 colony-forming units (CFU)/g dried soil. Fertilization was at 75 ppm nitrogen–potassium (N–K) weekly. Mycorrhizal root colonization was greater in plants grown inP.ultimumsoil at each density than in plants grown in soil withoutP.ultimum, as determined by the root segment method and at 132 and 38 CFU/g as determined by the root length method. Plant height and foliar P content of mycorrhizal plants were greater than of nonmycorrhizal plants when grown in soil infested with 38 CFU/gP.ultimum. Foliar manganese (Mn) content was greater in nonmycorrhizal than mycorrhizal plants when grown inP.ultimumsoil at each density. Mycorrhizal plants had lower finalP.ultimumpopulations in rhizosphere soil than nonmycorrhizal plants when grown in soil infested with 38 CFU/gP.ultimum. Densities ofPythium ultimumwere greater in rhizosphere compared with nonrhizosphere soil in the absence of mycorrhizae.

ISSN:0008-4026    

DOI:10.1139/b84-211

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Conventional autografts between severed internodes ofSedum telephoidesattained a tensile strength of approximately 75 g breaking weight (BW)/mm2graft area (GA) by 20 days after grafting. Approach grafts between cut surfaces were characterized by a tensile strength of approximately 42 g BW/mm2 GA by 10 days after grafting. Approach grafts in which membrane filters were inserted between the grafting surfaces attained a tensile strength of approximately 10 g BW/mm2 GA by 5 days after grafting. These results indicate that the cell wall deposition responsible for the initial cohesion of the stock and scion contributes approximately 13% of the tensile strength of the graft union in compatibleSedumautografts. Similarly, the interdigitation of callus cells and vascular redifferentiation (and the relatively small amount of wall deposition associated with each) contribute approximately 44 and 43%, respectively, to the tensile strength of theSedumgraft union. The data suggest synergistic interaction between different mechanisms of graft formation.

ISSN:0008-4026    

DOI:10.1139/b84-212

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Four new species ofMallomonas(Chrysophyceae),Mallomonas scrobiculatasp. nov.,Mallomonas serratasp. nov.,Mallomonas labrinthinasp. nov., andMallomonas favosasp. nov., are described from transmission electron microscopy of silica-scale structure of specimens from lakes and ponds in Ontario, Canada. All four are of theTorquataeseries (characterized by the uniquely shaped anterior collar scales with attached bristles and rhomboidal body scales lacking bristles) and are distinguished from others in the series (e.g.,M.mangoferaHarris & Bradley,M.alveolataDürrschmidt, andM.pumilioH. & B. em. Asm. Cronb. & Dürrs.) by the distinctive (and constant) structure and ornamentation of their scales.

ISSN:0008-4026    

DOI:10.1139/b84-213

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

TheCarex maclovianaaggregate consists of several phenetically similar taxa in western Canada and Alaska. Small morphological differences among the taxa have led to treatments recognizing either one more inclusive or six less inclusive species. A detailed morphotaxonomic investigation was initiated to delimit species and describe phenetic relationships among them. Results from study of herbarium specimens from the entire geographic range of each taxon and various numerical analyses of Canadian and Alaskan material indicate the taxaC.micropteraMack.,C.festivellaMack., andC.limnophilaHermann comprise one species;C.haydenianaOlney is another species, phenetically similar to the first, andC.maclovianaD'Urv. andC.pachystachyaCham.exSteud. are two similar but distinct species. The species were also determined to have different chromosome numbers, geographic distributions, and ecological preferences. A previously unrecognized group of specimens, designated "stubby," was recognized and included in all the analyses to determine its phenetic position within the aggregate. It is concluded that "stubby" represents an extreme form of the variableC.pachystachya.

ISSN:0008-4026    

DOI:10.1139/b84-214

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Thirty-two sites were seeded with wild rice. Based on the number of panicles per square metre, production in the sites was categorized as commercial, marginally commercial, or unsuitable for commercial production. Discriminant analysis was used to derive two functions which explained these production differences. High values for the first discriminant function, which was interpreted as a factor of sediment phosphorus concentration and sediment type, separated the sites suitable for commercial production. The second discriminant function separated the remaining two categories on the basis of sediment type and light penetration through the water column. Those sites unsuitable for commercial production had higher values for this function than those sites which produced marginally commercial growth. Further research is needed into the spatial and temporal variations of the significant environmental variables before any recommendations can be made on the criteria for selecting potential wild rice sites.

ISSN:0008-4026    

DOI:10.1139/b84-215

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Rhizoids ofFucus spiraliswere cultivated axenically in the artificial seawater ASP6 F2. Experiments were made to increase the filamental growth as well as to induce adventive primordia (plantlets). Additions of such carbon compounds as glucose, acetate, and formate had no favourable effects even in concentrations as low as 1∙10−4 M. Mannitol killed the rhizoids in higher concentrations and inhibited growth even in a concentration as low as 1∙10−5 M. Higher concentrations of glycerol also inhibited growth, but 1∙10−4 Mwas an exception as it initiated plantlets. Many simple phenolic compounds induced plantlets. Among the most active substances were phenylacetic acid,p-hydroxyphenylacetic acid, 3,4-dihydroxybenzoic acid,o-hydroxybenzoic acid, ando-acetoxybenzoic acid, with optimal effects in the concentration range of 1∙10−7to 1∙10−6 M. β-Indolylacetic acid strongly influenced the dry weight as well as plantlet formation at concentrations of 1∙10−8to 1∙10−7 M, with 1∙10−8 Mfavouring plantlet induction. It is obvious that β-indolylacetic acid plays an important role in the earlier stages of the deve

ISSN:0008-4026    

DOI:10.1139/b84-216

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Erwinia carotovoraproduces pectate lyases (endo-PGTE) on sterilized beans hypocotyls. Two endo-PGTE fractions were isolated and purified by electrofocusing. The action of these enzymes on the ultrastructure of cortical cells of pumpkin roots was very similar to the action of the whole bacterium.Erwinia carotovoragrown on tritiated amino acid supplemented medium produced [3H]endo-PGTE. By incubating the host tissues with3H-labelled enzymes and by subsequent autoradiographic analysis it was possible to localize the endo-PGTE inside the cells. Thus, it was shown that the enzyme (the complete molecule or only a peptide part thereof) was transported towards the vacuole. It is suggested that the endo-PGTE acts on the filamentous polysaccharide extensions which bind the external surface of the plasmalemma to the cell wall.

ISSN:0008-4026    

DOI:10.1139/b84-217

出版商:NRC Research Press    

年代:1984

数据来源: NRC

摘要:

Embryogenic callus was induced from young, unemerged inflorescences ofPennisetum americanumcultured on Murashige and Skoog's medium supplemented with different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D). The amount and quality of the embryogénie callus and the rapidity with which it was formed depended on the age of the explant and the concentration of 2,4-D. Best results were obtained from explants with floral primordia at the earliest stages of development and with 2.5 mg/L 2,4-D. The compact, embryogenic callus originated from the floral primordia. Subsequent differentiation of the callus led to the formation of subepidermal layers of embryogenic cells. These richly cytoplasmic cells contained numerous starch grains. Increase in cell wall thickness, cell separation, and a sequence of internal segmenting divisions in single embryogenic cells led to the formation of embryoids.

ISSN:0008-4026    

DOI:10.1139/b84-218

出版商:NRC Research Press    

年代:1984

数据来源: NRC