摘要:

Two autotetraploids (2n = 4x = 24) were produced by colchicine treatment of dry seeds ofLotus tenuisWaldst. et Kit. Triploids (2n = 3x = 18) were obtained by backcrossing the tetraploids to normal diploid plants. Primary trisomies (2n = 12 + 1) were obtained by selfing the triploids. A morphological comparison was made between a randomly selected diploid, a tetraploid, and five trisomic plants. The trisomics could be distinguished distinctly from the diploid and tetraploid using 12 quantitative phenotypic traits. Two traits, bract index and number of flowers per umbel, were not significantly different between all three cytotypes (2x, 2x + 1, 4x). By means of morphological analyses it was possible to select trisomic plants for presumably different trisomes prior to detailed cytological analyses of individual chromosomes.Key words: aneuploidy, tetraploids, Fabaceae,Lotus tenuis, morphological traits, triploids, primary trisomics.

ISSN:0008-4026    

DOI:10.1139/b97-834

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

Both ongoing and future studies of saskatoon (Amelanchier alnifoliaNutt.) fruit would benefit from a maturity index that could be referred to as as an indicator of fruit development. Accordingly, two cultivars of saskatoon fruit (Northline and Smoky) were sorted subjectively into nine maturity and ripeness stages based on differences in size and color. The physicochemical attributes of each stage were then characterized in detail. Color ranged from mostly green (stages 1–4) to white–pink (5) to pink (6) to red (7–8) to purple (9). The fastest gains in fresh and dry weights occurred over the later stages of development (from stages 5 to 9), while increases in fruit diameter between stages 1 and 9 were linear. Fruit firmness declined substantially between the first and the fifth maturity stages and then only slightly as ripening progressed to maturity class 9. Fruit nitrogen concentration decreased throughout development as did pH, chlorophyll, and phenolics. Fruit soluble solids, the ratio of soluble solids to titratable acidity, and anthocyanins increased from the fourth to the ninth stage of development. Glucose and fructose concentrations were about equal, increased about eightfold from class 4 to 9, and along with sorbitol were the major carbohydrates in fruit. Starch was nondetectable in fruit at all stages. Succinate was the predominant organic acid in immature fruit; however, levels declined with advancing maturity, and malate was the most concentrated organic acid in mature fruit. Changes in the relative concentrations of quinate, galacturonate, citrate, pyruvate, cis-aconitate, fumarate, and oxalate were also characterized with advancing maturity. In total, the concentration of organic acids dropped at least twofold as fruits developed from class 1 to 3, then declined relatively slowly through the remaining developmental stages. Cultivar variability in physicochemical attributes was relatively small and insignificant with regard to sorting and classifying fruits according to maturity. It is proposed that this nine-point maturity index be adopted for future studies on saskatoon fruit growth and development.Key words:Amelanchier alnifolia, fruit, maturity class, ripening, organic acids, sugars.

ISSN:0008-4026    

DOI:10.1139/b97-835

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

In some British Columbia forests, western red cedar (Thuja plicataDonn ex D. Don) grows well in soils with phosphorus (P) mainly in organic form and shows less response to P fertilization than other conifers. It was hypothesized that cedar or their associate arbuscular mycorrhizae could mineralize organic P. In a year-long greenhouse study, 2-year-old cedar trees in Turface were fed every 9 days with one of 11 P treatments (in Long Ashton solution): no P; high and low phytic acid (for all treatments, high is 50 mg P∙L−1, and low is 10 mg P∙L−1); high and low ATP; high and low glycerophosphate; high and low pyrophosphate; high and low orthophosphate. Ten mycorrhizal trees were used per treatment; of these, five trees per treatment were treated with the fungicide benomyl, which significantly reduced colonization in only two treatments. Growth was good with high rates of glycerophosphate, ATP, and pyrophosphate; low rates of these compounds resulted in P deficiencies. The trees grew poorly with phytic acid, which may have been adsorbed to the Turface, and which may have complexed Ca, Zn, and Cu from the nutrient solution, inducing deficiencies. The P source influenced the activities of rhizosphere acid and alkaline phosphatase, but had no significant effect on phosphodiesterase or pyrophosphatase activity. Use of the fungicide benomyl caused a significant increase in foliar N, either directly from the fungicide or indirectly from effects on N cycling.Key words:Thuja plicata, arbuscular mycorrhizae, phosphat

ISSN:0008-4026    

DOI:10.1139/b97-836

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

Small subunit ribosomal DNA has been sequenced from seven members of the ascomycete order Caliciales s.l. (Calicium adspersum,Cyphelium inquinans,Texosporium sancti-jacobi, andThelomma mammosum(Caliciaceae),Chaenothecopsis savonicaandStenocybe pullatula(Mycocaliciaceae), andSphinctrina turbinata(Sphinctrinaceae)), included in a matrix of 58 homologous ascomycete sequences and analysed with maximum parsimony analysis. The result shows the Caliciaceae to be a strongly supported monophyletic group within the Lecanorales s.l., although the jackknife support for a monophyletic Lecanorales is low. Mycocaliciaceae and Sphinctrinaceae form a well-supported monophyletic group, grouping with representatives of Eurotiales and Onygenales. This larger group is the sister group to Lecanorales, but the support for this sister-group relationship and the monophyly of the group consisting of Mycocaliciaceae–Sphinctrinaceae and Eurotiales–Onygenales is low. The evolution of the prototunicate ascus is discussed, and it is concluded that there is neither any evidence for a monophyletic Caliciales s.l., nor for the suggested group "Euascomycetideae" sensu Tehler, with the prototunicate Caliciales being the sister group to the rest of the true ascomycetes. Prototunicate asci are shown to have reappeared at least four times in the evolution of the ascomycetes.Key words: Ascomycetes, lichens, molecular evolution, phylogeny, ribosomal DNA, 18S rDNA.

ISSN:0008-4026    

DOI:10.1139/b97-837

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

Treatment of suspension-cultured larch cells (Larix deciduaMill.) with an elicitor derived from the cell wall ofFusarium oxysporumSchlecht. triggers very rapid defence responses like an oxidative burst and an increased calcium influx from the medium into the cell, all occurring within minutes after elicitation. These rapid responses are followed by a much slower set of changes like increased activities of phenylalanine ammonia-lyase and peroxidases and enhanced lignin biosynthesis. This paper describes both rapid and slow reactions of a cell culture derived from a woody plant to an elicitor from a facultative pathogen. Experiments concerning the transduction of the elicitor signal showed that the presence of calcium in the medium is indispensable for all elicitor responses of larch cells. It can be demonstrated that H2O2is not a part of the signal chain. The importance of inositol phosphates and protein phosphorylation were studied using inhibitors. Neomycin, an inhibitor of the phosphoinositol pathway, blocked only the slower responses whereas staurosporine, an inhibitor of protein kinases, blocked both rapid and all the slower reactions. These results support the hypothesis that phosphorylation plays an important role even in very early stages of the signal transduction.Key words: elicitor,Fusarium oxysporum, H2O2,Larix decidua, lignin.

ISSN:0008-4026    

DOI:10.1139/b97-838

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

Growth, reproduction, and biomass allocation were studied in three perennial root hemiparasites,Castilleja integraGray,Castilleja miniataDougl.,Castilleja chromosaA. Nels., and the annual hemiparasiteOrthocarpus purpurascensBenth. grown either without or with a host plant. In addition, the effects of the hemiparasites on the host plants were investigated. All four hemiparasites could grow without a host, indicating that they are facultative parasites;O.purpurascensandC.chromosaproduced flowers without a host. However, shoot mass of parasites with a host was 3–41 times that of parasites without a host. ForC.miniata,C.chromosa, andO.purpurascensthe growth of parasites grown with the legumeMedicago sativaL. was compared with that of parasites grown with the grassLolium perenneL. The legume was consistently a more beneficial host than the grass. InC.miniataandC.chromosa, patterns of biomass allocation were also influenced by the host type. The proportion of biomass allocated to roots was lower in parasites grown with the legume than in plants without a host, whereas it was higher in parasites grown with the grass. The parasites had strong negative effects on host growth, but the extent of host damage depended on the particular parasite–host combination.Castilleja chromosaandO.purpurascensaffected the growth of the legume more strongly than that of the grass, whereasC.miniataaffected the grass more strongly than the legume. Grasses parasitized byC.miniataallocated more biomass to roots than unparasitized grasses. In the other parasite–host associations the pattern of biomass allocation of the host was not influenced by parasitization. Because the biomass produced by the four hemiparasites was lower than the reduction in host biomass caused by parasitism, the parasites reduced total productivity. Therefore, the studied hemiparasites may potentially affect the structure and diversity of their communities.Key words: biomass allocation, host damage, parasite benefit, parasitic plant.

ISSN:0008-4026    

DOI:10.1139/b97-839

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

Biological effects of ion beams with different ranges and linear energy transfers (LETs) were investigated inNicotiana tabacumL. Mature pollen was exposed to doses of 1400 Gy of 6 MeV4He2+or 1000 Gy of 50 MeV4He2+, 15 MeV12C4+, or 460 MeV40Ar13+and used to pollinate non-irradiated flowers (I0generation), resulting in I, seeds. I1plants were self-pollinated, and mutations were analyzed in the I2generation. Seed formation in the I0generation was greatly reduced in all treatments except where12C4+irradiated pollen was used. Germination rate and survival rate in the I1generation were also reduced in the seeds generated from crosses with pollen irradiated with 6 MeV4He2+and12C4+beams. Furthermore, chromosome and morphological aberrations in I1plants were observed. However, in 50 MeV4He2+and40Ar13+regimes, no seeds germinated. In the I2generation, chlorophyll mutants were very scarce. Morphological mutants were obtained at a frequency of 5.7 × 10−3and 7.9 × 10−3in the progeny of 6 MeV4He2+and12C4+regimes, respectively. It is concluded that the penetration depth is important for inducing mutation and also that pollen can be used for obtaining mutations induced by ion beams with very short penetration depths.Key words: ion beam, mutation,Nicotiana tabacum, pollen.

ISSN:0008-4026    

DOI:10.1139/b97-840

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

Allelopathic effects of cyanobacterial inoculum on soil characteristics and cereal growth were investigated. Research established the alteration of chemical characteristics of the soils inoculated with different concentrations of cyanobacterial inoculum. Inoculated soils, compared with uninoculated soils, sometimes had significantly different values for chemical characteristics such as pH, electrical conductivity, organic matter, organic N, total phenolics, and exchangeable cations such as Cu, Zn, Na, K, Mg, and Ca as the level of inoculum increased. Despite a significant increase in organic nitrogen in the inoculated soils, root growth of rice and wheat was suppressed. The total phenolic content of inoculated soils increased in proportion to the concentration of inoculum added and the suppression of root growth. It is, therefore, suggested that prior to formulating and recommending cyanobacterial inocula as biofertilizers, their allelopathic aspects should be studied to determine a soil to algae ratio having minimum (least altered) chemical characteristics and nonsignificant allelopathic influences on each other.Key words: allelopathy, cyanobacterial inoculum, organic N, phenolics, rice.

ISSN:0008-4026    

DOI:10.1139/b97-841

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

To identify monophyletic groups within the smut fungi and related taxa, characteristics of hyphal septation and zones of host–parasite interaction were analyzed by serial-section electron microscopy of 139 species belonging to 50 smut and 10 allied genera. Our results support the hypothesis of the existence of two phylogenetically separate lines of smut fungi. The first line, the Microbotryales, is composed ofAurantiosporium,Fulvisporium,Liroa,Microbotryum,Sphacelotheca, andUstilentyloma, which are distributed into the Ustilentylomataceae and Microbotryaceae. The second monophyletic line, the Ustilaginomycetes, is formed by the remaining smut fungi studied here together with the Exobasidiales, Graphiolales, and Cryptobasidiales (in the traditional sense). The ultrastructural analysis identifies three lineages within the Ustilaginomycetes. The Entorrhizomycetidae are represented byEntorrhiza. The Ustilaginomycetidae consist of the Urocystales and Ustilaginales. The Exobasidiomycetidae are composed of the Doassansiales, Entylomatales, Exobasidiales, Georgefischeriales, Graphiolales, Microstromatales, and Tilletiales. The Entorrhizomycetidae, Exobasidianae, Entorrhizales, Entylomatales, Doassansiales, Georgefischeriales, Microbotryales, Microstromatales, Tilletiales, Urocystales, Entorrhizaceae, Entylomataceae, Georgefischeriaceae, Mycosyringaceae, Rhamphosporaceae, and Ustilentylomataceae are proposed as new taxa. The descriptions of the Exobasidiomycetidae, Ustilaginomycetidae, Exobasidiales, Ustilaginales, Doassansiaceae, Tilletiaceae, and Ustilaginaceae are emended. Some species ofUstilagoare transferred toMicrobotryum.Key words: basidiomycetes, classification, Exobasidiales, Graphiolales, phylogeny, smut fungi, ultrastructure.

ISSN:0008-4026    

DOI:10.1139/b97-842

出版商:NRC Research Press    

年代:1997

数据来源: NRC

摘要:

Ophiostomatoid fungi that resembleOphiostoma penicillatumwere isolated from insect-infested spruce (Piceasp.) in Japan as well asLarix deciduaMill. (European larch) in North America. Isolates were characterized based on morphology and could be separated into two distinct groups. Those from spruce in Japan representO.penicillatum, and are characterized by allantoid, slightly curved conidia. The North American isolates fromLarix deciduaare of a previously undescribed species, characterized by long, narrow conidia. The latter fungus is described asOphiostoma americanumwith an anamorph,Leptographium americanum.Key words:Ophiostoma penicillatum,Ips typographus,Ophiostoma americanum,Dendroctonus simplex,Larix decidua.

ISSN:0008-4026    

DOI:10.1139/b97-843

出版商:NRC Research Press    

年代:1997

数据来源: NRC