bluuebunny/crossref_metadata_2025 huggingface dataset:
Fungal deterioration of second-growth Douglas-fir logs in coastal British Columbia
Authors: Smith R. B. , Craig H. M. , Chu D.
Published: September 2008

Fungal deterioration of second-growth Douglas-fir logs, felled each month from August 1961 to May 1962, was studied 2, 4, and 6 years after felling. Decay increased from 10% of log volumes after 2 years to 47% after 6 years. The rate of decay, particularly for the brown cubical type, was greater for autumn- and winter-felled logs than for those felled in the spring and late summer, and closely paralleled the seasonal pattern of ambrosia beetle attack.Decay rates increased with decreasing log size, increasing percentage of sapwood, and increasing height of log above ground. For the same diameter of log, base logs decayed less rapidly than second logs, possibly because of their lower proportion of sapwood in relation to heartwood.Decay expressed as a percentage of total log volume (Y) may be estimated (R2 = 0.71) with the following equation: Y = 13.2 + 10.7X1 − 3.2X2, where X1 = years elapsed and X2 = d.i.b. (diameter inside bark) top of log.Of 30 wood-decay fungi isolated, Naematoloma sp. (N. capnoides or N. fasciculare), which causes a white rot, was associated with the most decay. Fomes pinicola was mainly responsible for brown cubical sap rot, while Poria monticola and P. carbonica caused a brown cubical heart rot at the ends of logs.The significance of variations in deterioration rate and fungal associates is discussed in relation to log durability and salvability.
Some Eurasian Puccinia species attacking Cardueae
Authors: Savile D. B. O.
Published: September 2008

Several lineages of Puccinia spp. attacking Cardueae are considered and species concepts are discussed, in an attempt to reach a better understanding of the evolution and relationships of these rusts and their host plants. Host specialization is an important aspect of parasite evolution and accordingly must be considered with morphology among taxonomic criteria. The importance of morphological changes adaptive to arid summers of the Mediterranean climate is emphasized. Several groups of rusts are discussed: microcyclic firm-pedicelled species, which have few taxonomic characters and may be derived from several distantly related heteroecious species; the Puccinia dioicae–P. hieracii lineage; the P. littoralis – P. helianthi lineage; and the P. centaureae – P. laschii lineage, including the somewhat distinct P. cnici group, which is linked to it through P. acarnae. Taxonomic changes include P. jaceae Otth var. solstitialis var. nov. on Centaurea solstitialis and var. diffusae var. nov. on Centaurea diffusa; P.aetheopappi sp. nov. on Aetheopappus pulcherrimus; P.oxyacanthae (Ahmad) comb. nov. on Carthamus oxyacantha; P. laschii Lagerh. var. fennica var. nov. on Cirsium heterophyllum in Finland, var. palustris var. nov. on Cirsium palustre, var. pannonici var. nov. on Cirsium pannonicum, and var. spinosissimi var. nov. on Cirsium spinosissimum; P. cnici Mart. var. crassiuscula nom. nov. on Cirsium eriophorum, ferox, and furiens, and var. turcica var. nov. on Cirsium vulgare var. hypoleucum in Turkey.
Autoecious Puccinia species attacking Cardueae in North America
Authors: Savile D. B. O.
Published: September 2008

Native rusts include P. irrequiseta on Centaurea americana and the following taxa on Cirsium: P. laschii var. laschii and var. xerophila var. nov.; P. altissimorum sp. nov. and var. horriduli var. nov.; P. californica and var. deserticola var. nov.; P. inclusa and vars. flodmanii, boreohesperia, brevifolii, and mexicana vars. nov. Introduced rusts include P. bardani on Arctium minus, P. carthami on Carthamus tinctorius, P. acroptili on Acroptilon (Centaurea) repens, P. centaureae var. centaureae on Centaurea nigra, P. cyani var. cyani and var. sublevis var. nov. on Centaurea cyanus, P. cnici var. cnici on Cirsium vulgare, and P. punctiformis on Cirsium arvense. The origins and relationships of the American Cirsium rusts are discussed in relation to those of the host plants. A hitherto disregarded adaptation to arid climates, the evolution of very fine and close urediniospore echinulations, is described and exemplified; it is suspected to function through improved retention of spores in the sorus in dry weather when susceptible young leaves are unavailable. Biological observations suggest means of limiting the spread of rusts of economic hosts and promoting those of some weedy hosts.
Factors affecting the survival of Trichometasphaeria turcica (Helminthosporium turcicum) on Zea mays
Authors: Scheifele G. L. , Nelson R. R.
Published: September 2008

Differential survival abilities of three isolates of Trichometasphaeria turcica were evaluated in the parasitic phase on maize by serial inoculations and by natural spread in the field. As related to the concept of stabilizing selection, the inbred line of maize met the criteria for a simple host and one isolate was a simple race and two were complex sensu van der Plank. In one mixture of two isolates, the simple isolate predominated within three generations, whereas the complex isolate predominated in the second mixture after four generations. Increased infection, disease, and sporulation efficiency, and a decreased incubation period were fitness attributes associated with the predominant isolate in each mixture. It is concluded that the genetic simplicity for virulence could not alone attribute to the survival fitness of the simple race. Other biological attributes of the organism, entirely independent of genes for virulence, govern the success or failure of a race in a given racial composition of the pathogen population during its parasitic phase on a given host substrate.Since the sole current rationale for stabilizing selection in non-obligate parasites focuses on fitness to survive saprophytically, these studies suggest that stabilizing selection in the parasitic phase deserves attention. Changes in the racial composition of a pathogen in the parasitic phase is important, not only in determining disease severity during a given year, but also in stabilizing selection and survival in the saprophytic phase. Attributes governing fitness to survive during the parasitic and saprophytic phases may not be correlated.
Notes on Sydowia polyspora
Authors: Smerlis E.
Published: September 2008

Sydowia polyspora (Bref. & v. Tav.) E. Müller is reported from Quebec on several conifers. Sclerophoma magnusiana Wilson & Hahn is established as an additional imperfect state of S. polyspora. Pathogenicity of S. polyspora is confirmed and demonstrated on several tree species.
Folate derivatives in ungerminated and germinated uredospores of wheat stem rust
Authors: Jackson A. O. , Samborski D. J. , Rohringer R. , Kim W. K.
Published: September 2008

Extracts of ungerminated uredospores and of uredospores germinated for 6 h and 12 h were assayed for folates with Lactobacillus casei, Streptococcus faecalis, and Pediococcus cerevisiae. These organisms did not respond to the extracts without conjugase treatment, indicating that most of the folates were present in conjugated form with more than three glutamic acid moieties per molecule. During the 6-h and 12-h germination periods the content of growth factors for L. casei declined to 70.9% and 46.0% of initial levels. In this same period, the content of growth factors for S. faecalis declined to 54.5% and 15.2% of initial levels, indicating an increase in the proportion of methylated folates during uredospore germination.This trend was confirmed in a detailed analysis of folate components after fractionation of the extracts on DEAE-cellulose columns. The folate profiles consisted of five peaks. Two peak fractions present in profiles from ungerminated spores contained mostly formylated folates and were greatly reduced or absent in profiles from germinated spores. A peak fraction composed of a 5-methyl-tetrahydrofolate conjugate was not observed in profiles of ungerminated spores but was predominant in those from spores germinated for 12 h.
The time-course of ion and water transport across decapitated sunflowers for 32 h after detopping
Authors: Sobey D. G. , MacLeod L. B. , Fensom D. S.
Published: September 2008

Sunflowers growing in water culture solution containing only six ions (K+, Na+, Ca2+, Mg2+, Cl−, and NO3−) were decapitated and the exudate was allowed to accumulate in vinyl tubes. Measurements of biopotential, exudation rate, and ion concentration in the exudate and the nutrient medium were made at 4-h intervals during the 32-h period after detopping. The exudation rate, fluxes for each ion, biopotentials, and Δ E values for each ion were plotted on a time axis. With the fluxratio equation, chloride, nitrate, and potassium were observed to be entering actively, whereas for the other cations the gradient inward was passive. The active or passive movement for each ion and the diurnal cycles in exudation and ion fluxes changed as time after detopping increased. These changes might be accounted for in terms of the effects of detopping which remove the supply of energy compounds necessary for the normal functioning of the root.
Chromosome numbers of some Mexican and Colombian grasses
Authors: Gould F. W. , Soderstrom T. R.
Published: September 2008

Chromosome numbers are reported for 73 collections of grasses from the states of Yucatán, Campeche, Oaxaca, and Chiapas in Mexico and in Colombia from Amazonas, Caquetá, and Cundinamarca. Included in the reports are counts for 61 species representing 31 genera. The first chromosome records are reported for the genera Hymenachne and Neurolepis, and the following 25 species: Bothriochloa schlumbergeri, Chloris inflata, Digitaria obtusa, Eragrostis acutiflora, E. domingensis, E. maypurensis, E. trichocolea, Eriochloa aristata, Homolepis aturensis, Hymenachne donacifolia, Ichnanthus axillaris, I. breviscrobs, I. tenuis, Lasiacis ruscifolia, L. sorghoidea, Muhlenbergia tenella, Neurolepis aperta, Olyra loretensis, Panicum mertensii, P. pulchellum, P. sellowii, Paspalum orbiculatum, Pereilema crinitum, Setaria poiretiana, and Sporobolus jacquemontii. Counts differing from those previously reported are given for Chloris chloridea, Eragrostis viscosa, and Paspalum paniculatum.
Influence of continuous and periodic soil water conditions on root necrosis of holly caused by Pythium spp.
Authors: Biesbrock J. A. , Hendrix Jr. Floyd F.
Published: September 2008

Root damage in Helleri holly induced by P. vexans was affected more by differences in soil water saturation capacities (70 and 90%) than by differences in mean soil temperatures (18, 24, and 30 °C). By contrast, root damage in Helleri holly induced by P. irregulare was affected more by differences in mean soil temperatures than by differences in soil water saturation capacities. Root damage in Convexa holly induced by P. vexans was affected more by a periodic saturation of prolonged duration than by differences in soil temperatures. By contrast, root damage in Convexa holly induced by P. irregulare was affected more by differences in soil temperature than by periodic saturations of prolonged and unprolonged durations.<
Effects of mining pollution on vascular plants in the Northwest Miramichi River system
Authors: Besch K. W. , Roberts-Pichette Patricia
Published: September 2008

Copper-zinc mining pollution effects on riparian and aquatic vascular plants were studied in the Northwest Miramichi River system of northern New Brunswick. After a period of 8 years, the riparian vascular flora of the river system's gravel shores has been completely eliminated or seriously reduced. The most sensitive plants are the submersed aquatic species, followed by riparian dicotyledons. Monocotyledons are less sensitive than dicotyledons and Equisetum arvense the least sensitive species. A rough index of pollution severity was devised based on the absence of species or species groups which would normally be present under unpolluted conditions.
Melanospora sphaerodermoides on seed of Agrostis palustris
Authors: Shoemaker R. A. , Smith J. Drew
Published: September 2008

The pyrenomycete Melanospora sphaerodermoides Grove is redescribed and illustrated from an abundant collection in a consignment of Seaside creeping bentgrass seed from Albany, Oregon, U.S.A.
The haustorium of Geocaulon lividum; a root parasite of the Santalaceae
Authors: Warrington Patrick D.
Published: September 2008

The haustorium of the santalaceous root parasite, Geocaulon lividum, is described and the known host genera listed. The haustorium develops as a lateral outgrowth of the root and does not differentiate fully until penetration of the host has occurred. Clasping folds in the outer portion of the haustorium attach the haustorium firmly to the host. After attachment, the core of the haustorium penetrates through to the xylem of the host. The vascular core consists of three zones: mother root zone, transitional zone, and haustorial zone. Each zone is characterized by distinctive vessel elements the occurrence of which is graphically illustrated.
Emergence of the aeciospore germ tubes of Cronartium coleosporioides (=Peridermium stalactiforme) as observed by scanning electron microscope
Authors: Hiratsuka Y.
Published: September 2008

Germ tubes of Cronartium coleosporioides Arth. (= Peridermium stalactiforme Arth. and Kern) emerged between processes through short irregular slits. Germ tube walls were folded when they emerged and expanded after the emergence.
Nucleoli in differentiated germ tubes of wheat rust uredospores
Authors: Dunkle Larry D. , Wergin William P. , Allen Paul J.
Published: September 2008

Nucleoli observed by electron microscopy are illustrated in germ tubes of wheat stem rust uredospores which have been induced by heat shock to differentiate infection structures. The presence of nucleoli in these structures suggests that this obligate parasite may possess the capacity of synthesizing ribosomal RNA independently of its host. In addition to nucleoli, heterochromatin is characteristically observed appressed to the inner membrane of the nuclear envelope. This material is associated with distinct cytoplasmic structures which are appressed to the outer membrane of the nuclear envelope and resemble developing centrioles in other fungi.
The Douglas-fir forests of Banff and Jasper National Parks, Canada
Authors: Stringer Paul W. , La Roi George H.
Published: September 2008

Twenty stands of uniform, mature, undisturbed Pseudotsuga menziesii var. glauca forest were selected in Banff and Jasper National Parks, using a combination of airphoto and ground surveys. Quantitative sampling methods were used to describe their floristic composition, vegetation structure, and physical habitats.Scattered trees of Pinus contorta, Picea glauca, and Populus tremuloides occurred in the Pseudotsuga forests. The poorly developed shrub strata contained Shepherdia canadensis, Rosa acicularis, Spiraea lucida, Juniperus communis. Major herb, dwarf shrub, bryophyte, and lichen species were Elymus innovatus, Calamagrostis rubescens, Fragaria virginiana, Astragalus decumbens, Aster conspicuus; Arctostaphylos uva-ursi, Linnaea borealis; Hylocomium splendens, Abietinella abietina, Tortula ruralis; Peltigera canina. A cyclical pattern of vegetation change is related to the death, replacement, and maturation of Pseudotsuga trees.Relations between vegetation and physical habitat were analyzed by simple correlation and multiple regression. Available potassium in soil, stand age, and slope exposure were most influential in regression equations for tree stratum development. Understory strata were primarily correlated with tree stratum development.A two-dimensional stand ordination based on the vegetational similarity of subordinate vascular strata showed a pronounced separation of Banff and Jasper Pseudotsuga forests, and prompted recognition of two new climax associations (sensu Daubenmire): Pseudotsuga / Elymus innovatus in Jasper; Pseudotsuga / Calamagrostis rubescens – Elymus innovatus in Banff. Habitat differences between the two associations include macroclimate, parent materials, and soil moisture.
Black stain in yellow cedar heartwood
Authors: Smith Roger S.
Published: September 2008

Black stain in yellow cedar heartwood and the probable causal fungi are described, both macro- and micro-scopically. The decreased decay resistance of naturally and experimentally blackstained heartwood to several wood-destroying fungi is shown. The possible role of black-stain fungi as precursors of decay fungi in the colonization of yellow cedar heartwood is discussed.
Floret development, embryology, and systematic position of Oryzopsis hendersoni (Gramineae)
Authors: Mehlenbacher, Jr. Lyle E.
Published: September 2008

Previous research has shown that Oryzopsis hendersoni shares two features with Stipa and one with Oryzopsis. A study of floret development and embryology was undertaken to obtain more points for comparison. Most of the 26 features of O. hendersoni resulting from this study are characteristic of Stipa and not Oryzopsis. Therefore, it is proposed that O. hendersoni be transferred to Stipa.Evidence from this and other studies demonstrates that the ovules of grasses and of certain other angiosperms are stem-borne; that the development of grass lodicules can be leaf-like, stem-like, or intermediate; and that the grass carpel develops as a single, continuous, leaf-like structure. This developmental evidence disproves the generally accepted notions that all angiosperm ovules are carpel-borne, that all grass lodicules are leaf-like, and that the grasses have three carpels. Since these notions have resulted from the acceptance of completely speculative phylogenies, it is proposed that such misleading phylogenies be rejected and avoided in the future.It is also recommended that, because the word homology means different things to different people, the word homology be replaced by clear and common, but equally concise, terminology.
A thin-layer chromatographic study of the phenolics of the genus Aegilops. I. Numerical chemotaxonomy of the diploid species
Authors: Kaltsikes P. J. , Dedio W.
Published: September 2008

A two-dimensional thin-layer chromatographic study of the phenolics of young leaves provided the means for a numerical chemotaxonomic study of the diploid species of the genus Aegilops L. A great amount of variation in types and concentration of these compounds was found within A. squarrosa. Var. anathera, typica, and meyeri, of the ssp. eusquarrosa, were more related to ssp. strangulata than to each other. However, since the subspecies are morphologically distinct, their present taxonomic position should be retained. A. comosa was distinguishable from all other species by the presence of a violet fluorescing compound, while A. mutica was distinct from the others by the presence of a blue and a yellow fluorescing compound. Members of the Sitopsis section exhibited a high degree of similarity in composition of phenolic compounds. Based on phenolic contrast, A. umbellulata should be placed in a section apart from A. caudata while the rest of the diploid species should remain as presently classified. All Aegilops species were distinctly different from T. aegilopoides and T. monococcum and should be retained as separate generic entities.
A thin-layer chromatographic study of the phenolics of the genus Aegilops. II. Numerical chemotaxonomy of the polyploid species
Authors: Kaltsikes P. J. , Dedio W.
Published: September 2008

Based upon a thin-layer chromatographic study of the phenolics of young leaves of the species of the genus Aegilops, in which affinities both within and among diploid and polyploid groups were compared, the following conclusions were drawn. No new compounds were found in the polyploid Aegilops species. A. ovata must have arisen from A. umbellulata and A. comosa. A. columnaris probably contains genetic material derived from members of the Sitopsis section. A. biuncialis contains parts of the genome of A. comosa and parts from some member of the Sitopsis section. A. variabilis contains an S or modified S genome. A. triuncialis contains the C and Cu genomes. A. cylindrica contains the genomes C and D. A. crassa(4x) has an S genome in its constitution. A. ventricosa seems to contain parts of the A. caudata genome. A. crassa (6x) contains one D genome, probably from A. squarrosa, one from A. bicornis, and the third genome appears to contain parts from the M and S genomes. A. juvenalis and A. triaristata (6x) contain a modified S genome.The present study supports the hypothesis that extensive natural hybridization and introgression has taken place during the evolution of the polyploid species.
Decomposition of loblolly pine bark by soil- and root-inhabiting fungi
Authors: Kuhlman E. G.
Published: September 2008

A modified soil-block test was used to compare the bark-decomposing ability of various soil- and root-inhabiting fungi. Bark of Pinus taeda was highly resistant to decomposition by all 31 fungi tested. A brown-rot fungus, Lenzites saepiaria, caused the most weight loss, but weight losses due to decay by all fungi varied only from 3 to 15%. Isolates of Mucorales produced 3–8% weight losses from stem bark in 12 weeks. Available nutrients were used within 6 weeks; longer incubation resulted in little additional decomposition. Losses in weight from root bark and stem bark were similar, indicating little nutritional difference between these two substrates.Extraction of stem bark with ethanol or water before incubation with Fomes annosus, L. saepiaria, or Scytalidinun lignicola did not increase the amount of decomposition. This suggests that extractives in the bark may not be responsible for the slow rate of decay. Since autoclaving of the bark before incubation with the fungi enabled the fungi to cause more weight loss than did gas sterilization of the bark, the primary reason for the slow rate of decomposition by fungi is considered to be the complex molecular structure of the bark constituents.
Leaf area development on different shoot types in a young aspen stand and its effect upon production
Authors: Pollard D. F. W.
Published: September 2008

Different shoot types in aspen crowns carried leaves of different ages; leaders continued to produce leaves until early August and always carried some young leaves, whereas short shoots completed development by mid-June. Development of foliage on long shoots was intermediate between that on leaders and short shoots. Leaf area index of the 6-year-old stand reached a maximum of 2.4, of which 2.1 was contributed by short-shoot foliage. The rest was formed by leaders and long shoots. Young leaves on leaders and long shoots were not sufficient to influence total production in the stand appreciably, even though young aspen leaves may have high photosynthetic efficiencies. These young leaves could, however, influence height growth and lateral development of the canopy.
Cone serotiny and inbreeding in natural populations of Pinus banksiana and Pinus contorta
Authors: Teich A. H.
Published: September 2008

Cone serotiny in jack and lodgepole pine was studied by applying the Hardy–Weinberg law to data from several populations, and by examining data on progeny of individual trees. Cone serotiny appears to be governed by a single gene with two alleles. The phenotype of the heterozygote is intermediate to that of both homozygotes and is subject to environmental influence. Because of this a proportion of the heterozygotes may have been misidentified as homozygotes, which inflated the inbreeding coefficient, making it unreliable. Progeny tests or other means of correctly identifying heterozygotes would allow the use of cone serotiny as a marker gene for hybridization and relate populations by their similarity of gene frequencies.
Effects of temperature on growth, proteins, peroxidases, protease, RNA, RNase, and HCN production of ageing cultures of a low-temperature basidiomycete
Authors: Sekhon Awatar S. , Colotelo Nicholas
Published: September 2008

Growth studies of a low-temperature hydrogen cyanide producing basidiomycete were carried out using a synthetic medium in solid, liquid static, and liquid shake cultures at various temperatures. At 1 °C growth was slower but more mycelium was produced in liquid static and liquid shake cultures than at 15 °C. Analyses of cell-free extracts by disc gel electrophoresis indicated that the patterns of protein and peroxidase isozyme bands varied markedly with age of culture and incubation temperature. The number of electrophoretic protein bands representing mycelium incubated at 1 °C was greater than that for mycelium incubated at higher temperatures. The number of protein bands decreased with increasing age of cultures but the decrease was less for cultures incubated at 1 °C than at higher temperatures. Protease activity of cell-free extracts was higher at 1° than at 15 °C. A higher level of ribonucleic acid (RNA) was observed for mycelium incubated at 1° than at 15 °C. Relative to RNA, RNase activity did not follow the same pattern at 15° as at 1 °C. At 15 °C, in younger cultures, RNase activity increased with decreasing amounts of RNA, but at 1 °C, increase in RNase paralleled increases in RNA. HCN was released earlier in cultures incubated at 15° than at 1 °C but higher levels were maintained longer at 1 °C.
A further note on the surface structure of Scenedesmus coenobium
Authors: Higham M. T. , Bisalputra T.
Published: September 2008

Observations of the surface structure of Scenedesmus quadricauda coenobium with the scanning electron microscope confirm, in general, results obtained previously by transmission electron microscopy. However, features such as ridges and the distribution and spatial relationship of various identities such as props, openings, and ridges can now be observed. The existence of bristles described by other authorities is questioned.
Photosynthetic apparatus in Selaginella. I. Morphology and photosynthesis under different light and temperature regimes
Authors: Jagels Richard
Published: September 2008

Several hydrophytic and umbrophilic species of Selaginella were grown in sterile culture and scrutinized for morphological and photosynthetic variability under light intensities between 0 and 500 ft-c and temperatures of 9° and 22 °C. Bleaching was induced by raising light intensity; and for a particular light intensity was enhanced by lowering temperature. Regreening could be achieved by reversing conditions. Branching patterns, leaf symmetry, and orientation of leaves to axis were also light dependent. Light levels which produced normal green plants for S. uncinata initiated only half-saturation photosynthetic rates. Photosaturating light intensities, if applied for several weeks, induced bleaching. Based on fresh or dry weight bleaching plants had lower photosynthetic rates than green plant's; but based on chlorophyll content the photosynthetic rates of green and bleaching plants were the same.
Photosynthetic apparatus in Selaginella. II. Changes in plastid ultrastructure and pigment content under different light and temperature regimes
Authors: Jagels Richard
Published: September 2008

The ultrastructural details of the chloroplasts of Selaginella are identical with those of higher vascular plants. During bleaching there is an "unstacking" of grana, but the integrity of the grana and connecting fretwork is maintained. Osmiophilic droplets, containing a red pigment identified as rhodoxanthin, increase during chromoplast formation. The other carotenoids and chlorophyll decrease during bleaching. Once plastids contain swollen grana, regreening is not possible. The results of this paper and the preceding one are combined to present a hypothetical scheme of events in the bleaching–regreening process in Selaginella.
Regenerative studies on the detached leaves of Echeveria elegans. Anatomy and regeneration of leaves in sterile culture
Authors: Raju M. V. S. , Mann Henry E.
Published: September 2008

Excised leaves, L1–L30, of Echeveria elegans Bgr. were cultured aseptically on an agar medium to study their regenerative capacity. The younger leaves tended to produce roots earlier than shoots and some had not produced shoots by the time of termination of the experiments. The older leaves produced shoots earlier than roots and in such instances the shoots appeared on the adaxial side. In no case was the appearance of shoots on the abaxial side of the leaf noticed and this suggested the possible manifestation of polarity of regeneration. The leaf regeneration to produce roots or shoots depended on the degree of vascular differentiation, particularly at the leaf base where regeneration normally occurs. In young leaves that had little or no vascular differentiation at the time of their isolation, abundant callus appeared in which the first primordia initiated were of roots. The old detached leaves had short petioles, which contained mature vascular tissue, and produced very little callus in culture.
Survival of Cochliobolus sativus conidia in pure culture and in natural soil at different relative humidities
Authors: Ledingham R. J.
Published: September 2008

Conidia of Cochliobolus sativus cultured on sterile wheat straw were nearly 100% germinable after 52 months when maintained at relative humidity of 50% or lower. At higher relative humidity, spore longevity was much reduced. Increased temperature decreased spore longevity. Comparable results were obtained in natural soil.
A new species of Draba in the Kananaskis Range of southwestern Alberta
Authors: Mulligan Gerald A.
Published: September 2008

A new yellow-flowered species of Draba, D. kananaskis G. A. Mulligan, n = 32, is described from the Kananaskis Range in southwestern Alberta. It is suggested that it may be an endemic in an area unglaciated during the Wisconsin.
Electrophoretic patterns of globulins and albumins in conifer seeds
Authors: Juo Pei-Show , Stotzky G.
Published: September 2008

The globulins and albumins in seeds of nine species of conifers were distinguished by disc electrophoresis. On the basis of their higher stain intensity, the slower moving proteins, located in the upper half of the separation gels, appeared to be dominant. Only one globulin and one albumin band were homologous in all species examined, although several globulin and albumin bands appeared to be common to many species. The degree of similarity in protein patterns between species classified within the same genus and the degree of difference between genera were not as great as those reported for seeds of some angiosperms.
Degeneration of leaf cells resulting from starvation after excision. I. Electron microscopic observations
Authors: Ragetli H. W. J. , Weintraub M. , Lo Esther
Published: September 2008

Mesophyll cells of Nicotiana glutinosa exposed to starvation in the light after leaf excision showed the following major changes: vacuolation of the cytoplast; rearrangement of chloroplast and nuclear material; accumulation of cytoplasmic crystals and of starch; evagination and increased perforation of the nuclear membrane; and lysis of the tonoplast. Rearrangement of chloroplast material resulted in extended, 3-dimensional arrays (pseudocrystalline bodies), composed of electron-dense globules 85–100 Å in diameter. The ultrastructural degeneration of cells within a leaf was unsynchronized, and the sequence of degenerative intracellular events was not fixed. These observations are compatible with an unequal distribution of "essential" metabolites among those cells. Cells suffering from starvation stress showed ultrastructural changes not observed in cells of aging attached leaves and vice versa. Thus, starvation stress does not merely accelerate the process of cell-aging, as it operates in attached leaves.
Degeneration of leaf cells resulting from starvation after excision. II. Correlation with water movement and effect on virus synthesis
Authors: Ragetli H. W. J. , Weintraub M. , Lo Esther
Published: September 2008

Excised Nicotiana glutinosa leaves increased their transpiration rate during the first 24 h of detachment to 1.5 times the rate of attached control leaves. Thereafter, the transpiration rate decreased to ca. 30% of the controls, without change in fresh weight. The turgidity of the excised leaves at low levels of water movement under normal atmospheric conditions was considered to reflect a state of cell hydration resulting in intracellular rearrangements and hydrolytic changes. Leaves exposed to starvation stress caused by excision for 96 h before TMV infection produced fewer lesions and less virus per cell than the appropriate controls. The lower overall virus level in the starved cells was the net result of a much reduced production of nearly standard-sized particles (270–330 mμ), and an increased production of short (30–170 mμ) particles. Viral production in cells exposed to starvation stress after inoculation, in normal atmosphere, was 15 times lower than was reported for 100% humidity. TMV-infected tissue effected intracellular changes in neighboring uninfected cells exposed to starvation stress.
Vascular plants from some localities in the western and northern parts of the Canadian Arctic Archipelago
Authors: Kuc Marian
Published: September 2008

The paper lists 123 species of vascular plants from several areas hitherto not investigated botanically: Masik River Valley, Banks Island; Eglinton Island; Fitzwilliam Owen Island; and Good Friday Bay, Axel Heiberg Island. Also, collections are listed from Meighen Island and from the vicinity of Eureka, Axel Heiberg Island, both areas where botanical work has been carried out earlier.
Environmental influence on symptom expression in Verticillium wilt of chrysanthemum
Authors: Busch L. V. , Schooley H. D.
Published: September 2008

Symptom expression in Verticillium wilt of chrysanthemums was found to be correlated with flowering. Regardless of the time of inoculation, symptoms did not appear until buds were apparent on the plants. The number of propagules recovered from these plants increased rapidly as they approached full bloom. The lack of symptoms in vegetative plants was not due to sparsity of either mycelial colonization of the xylem vessels or fungal propagules, but to some other factor.
Effects of Cronartium ribicola infection on rooting potential of detached Pinus monticola needle bundles
Authors: McDonald Geral I. , Hoff Raymond J.
Published: September 2008

Infection of needles by Cronartium ribicola J. C. Fisch. ex Rabenh. depressed the level of root initiation by needle bundles obtained from Pinus monticola Dougl. seedlings. The depression was influenced by genetic background of the seedlings, an indication that resistance to the pathogen and rooting ability were not independent traits in certain half-sib families.
Pollen diagrams from interior Labrador
Authors: Morrison Alastair
Published: September 2008

Six pollen zones can be distinguished in interior Labrador. The earlier zones represent the primary succession of vegetation from bare ground to boreal woodland or forest, which occupied about 500 years between 5700 and 5200 B.P. There have been only minor fluctuations in the nature of the vegetation since 5200 B.P. Radiocarbon dates show that the zones are contemporaneous over that part of the Lake Plateau within the Churchill River watershed, but similar vegetation changes occurred 1000 years earlier in the Kaniapiskau basin, further north, in New Quebec. These two areas must have been freed of a cover of glacier ice or lake waters immediately before 5700 B.P. and 6700 B.P. respectively.
Hormonal regulation of apical dominance in soybeans
Authors: Ali A. , Fletcher R. A.
Published: September 2008

Hormonal regulation of apical dominance in soybeans is dependent on the physiological stage of the lateral buds. In 7-day-old plants the cotyledonary buds are in an active state of mitosis and the application of a single hormone, gibberellic acid (GA) is effective in releasing the buds whilst indole acetic acid (IAA) is ineffective in inhibiting the buds of decapitated plants. In 16-day-old plants in which mitosis in the cotyledonary buds had ceased, a combination of both benzyladenine (BA) and GA was required for bud growth. BA initiated mitosis and GA promoted elongation. Application of IAA to the apical cut surface of these plants was effective in maintaining the inhibition of cotyledonary buds, and this inhibition could be overcome by a direct application of BA and GA to the inhibited buds. This study has shown that the growth of the inhibited cotyledonary buds in soybeans is regulated not only by auxins but by an interaction between auxins, cytokinins, and gibberellins. The effectiveness of any one of these hormones in inhibiting or promoting growth of the buds is dependent on the age of the plant.
Derivation of the springtime starch increase in balsam fir (Abies balsamea)
Authors: Little C. H. A.
Published: September 2008

The contents of starch, total sugar, crude fat, and moisture were determined during the spring (late March until mid-June) in needles, bark, and wood of 1-year-old balsam fir shoots variously shaded, defoliated, and girdled in late March. The starch content in control shoots peaked during the first week in June, about the time vigorous current shoot elongation began. Shading reduced the concentrations of both starch and total sugar throughout the experimental period, while defoliation decreased them after about mid-spring. Girdling increased the carbohydrate content during early spring in both shaded and unshaded shoots, but decreased it in defoliated shoots. It is concluded that the bulk of the starch accumulating in conifers during the spring is derived from current photosynthesis, the rest being regenerated from carbohydrates produced during the previous year and stored overwinter. Timing the lifting date to maximize the springtime accumulation of starch might be an important consideration when transplanting conifer seedlings.
Compartments of organic acids in the synthesis of asparagine and homoserine in pea roots
Authors: Mitchell D. J. , Bidwell R. G. S.
Published: September 2008

14C-Labeled aspartate and organic acids were supplied to pea-root pieces to elucidate the pathways of carbon leading to asparagine and homoserine synthesis. The pattern of labeling in the products, and the effects of competing non-radioactive acids on the distribution of 14C from labeled substrates, gave the following results. Supplied aspartate is not converted directly to asparagine or homoserine, but must first enter the Krebs cycle. If aspartate is an immediate precursor of either of these compounds, the synthetic pathways must be compartmented from externally supplied aspartate. Carbon leaves the Krebs cycle as succinate, and is converted to other 4-carbon acids in a metabolic system that is separated from the Krebs cycle and presumably outside the mitochondria. The pathway from succinate to homoserine proceeds via extramitochondrial fumarate and malate, and to asparagine via fumarate. Carboxylation of pyruvate (or a related three-carbon acid) leads to homoserine and asparagine via a symmetrical intermediate permitting equilibration of the two ends of the 4-carbon precursor. About four times more carbon from added pyruvate is converted to homoserine and asparagine via the Krebs cycle than by carboxylation.
Factors influencing the stratification process in seeds of Acer ginnala
Authors: Dumbroff E. B. , Webb D. P.
Published: September 2008

Experiments with seeds of Acer ginnala support the view that stratification is a phasic process strongly influenced by both physical and metabolic events. Rates of imbibition indicate that the pericarp provides a significant restriction to water uptake by the embryo. Whole seeds required 30 days of stratification at 5 °C before first germination, but removal of the pericarp reduced the time to half that value. Tests showed that oxygen was not a limiting factor, and a water-soluble extract from pericarps did not increase stratification time of seeds with their pericarps removed and testas pricked. There was an apparent correlation between water uptake and respiration throughout the 30-day period, and both factors followed a similar three-phase pattern. These results are similar to those previously reported for Acer saccharum.
Seasonal changes in carbohydrate and moisture content in needles of balsam fir (Abies balsamea)
Authors: Little C. H. A.
Published: September 2008

Starch, total sugar, fructose, glucose, sucrose, raffinose, crude fat, and moisture contents were determined for current and 1-year-old needles at about 2-week intervals throughout 1968. Seasonal fluctuations in moisture and carbohydrate content of each age of needles are described, compared, and related to seasonal changes in carbohydrate production and use.
Photosynthesis and respiration in black spruce (Picea mariana) parasitized by eastern dwarf mistletoe (Arceuthobium pusillum)
Authors: Clark J. , Bonga J. M.
Published: September 2008

Under controlled laboratory conditions, it was found that during summer black spruce branches parasitized by a dwarf mistletoe have a higher rate of apparent photosynthesis and dark respiration than unparasitized branches. In winter, parasitized branches have a lower rate of apparent photosynthesis and generally a higher rate of dark respiration than non-infected branches.
Synthesis and metabolism of homoserine in developing pea seedlings
Authors: Mitchell D. J. , Bidwell R. G. S.
Published: September 2008

Homoserine appears shortly after germination in pea seedlings and rapidly becomes the dominant soluble nitrogen component. It is synthesized only slowly from added 14C-glucose, and more rapidly from 14C-pyruvic and aspartic acids. Synthesis does not begin until the second day of germination, and increases thereafter. Homoserine is synthesized from added 14C-aspartic acid chiefly in the roots, and is translocated to the epicotyls. Added 14C-homoserine is converted rapidly into various alcohol-soluble and -insoluble components in the light, more slowly in darkness. Carbon from homoserine is widely distributed in the metabolism of epicotyls, and it is as effectively used as added aspartic acid. The results indicate that homoserine is involved in the mobilization and translocation of carbon and nitrogen reserves after germination in pea seedlings.
Pathological anatomy of the Dutch elm disease. Distribution and development of Ceratocystis ulmi in elm tissues
Authors: Pomerleau René
Published: September 2008

Extensive histological studies carried out, during 3 years, on more than 200 white elms (Ulmus americana L.), young and old, artificially or naturally inoculated with Ceratocystis ulmi (Buis.) C. Moreau, add more precision on the spread and location of the fungus in host tissues and the site of the pathogenesis. With new and improved techniques, characteristic spores and hyphae of the pathogen were clearly observed in vessels and never in other tissues and were sharply differentiated from cell contents and artifacts. Double bordered pits or the thin primary wall between secondary thickenings is the only means of passage of the fungus from one vessel to another. All fungus elements in culture and in tree are 1.0 μ or more in diameter, and no living structure of this species passed through a millipore filter of 1.2 μ. Hyphae and spores, observed in fibers and parenchyma cells in dead wood or close to a dead area of the stem, were attributed to other fungi.Clusters of spores and hyphae, frequently found in vessels of all types and sizes, do not alone explain leaf wilting.
A cytogenetic analysis of reaction to common root rot in some hard red spring wheats
Authors: Larson Ruby I. , Atkinson T. G.
Published: September 2008

Chromosome 5B is the most important chromosome differentiating the root rot resistance of the hollow-stemmed cultivars, Apex and Cadet, from the root rot susceptibility of the solid-stemmed cultivars, S-615 and Rescue. A pair of chromosomes 5B of Apex substituted for their homologues in S-615 usually made the latter as resistant to root rot as Apex. Conversely, the substitution of 5B from Rescue into Cadet made Cadet as susceptible as Rescue. The root rot reactions of the 5B monosomics of the cultivars and substitution lines, and of the F1 between S-615 and the S-615-Apex 5B substitution, showed that the genes for resistance and susceptibility are antimorphic alleles, with susceptibility dominant.The substitution of chromosome 2B or 2D from Apex for their homologues in S-615 increased the root rot resistance of S-615, but not to the same extent as did the substitution of chromosome 5B. Their effect, although usually hypostatic to that of 5B, was evident under some test conditions. Dosage studies showed that genes on chromosomes 2B and 2D promote the disease, those from Apex less than those from S-615. Substitutions of these chromosomes from Rescue into Cadet did not affect root rot reaction.
Meiosis and mitosis in Saprolegniaceae
Authors: Flanagan Patrick W.
Published: September 2008

The nuclei in hyphae, oospores, and gametangia of Achlya klebsiana and Saprolegnia ferax were examined by light microscopy after stain fixation with acetoorcein. It was found that the vegetative phase is diploid and that meiosis is not zygotic but is gametic in these organisms. The nuclear divisions in hyphae and germinating oospores were similar and were classically mitotic.
A checklist of marine algae of eastern Canada
Authors: South G. Robin , Cardinal André
Published: September 2008

A checklist of 371 species, subspecies, and varieties of benthic marine algae from eastern Canada is given, consisting of 157 Rhodophyceae, 127 Phaeophyceae, and 87 Chlorophyceae. Records for the entire coastline from Cape Chidley, Labrador, in the north to the New Brunswick – Maine border in the south are included, as well as from Anticosti Island, Magdalen Island, Sable Island, and St. Pierre and Miquelon. Mikrosyphar porphyrae Kuck. and Protectocarpus speciosus (Børg.) Kuck. are new records for the area.
Ultrastructure of Porphyra perforata infected with Pythium marinum, a marine fungus
Authors: Kazama Fred , Fuller Melvin S.
Published: September 2008

A marine species of Pythium, P. marinum Sparrow, was isolated from lesions occurring on Porphyra miniata collected at the north end of the Cape Cod Canal. Zoospores obtained from the isolates were used to infect Porphyra perforata artificially. The fine structure of the host–parasite interaction indicates that during penetration, the fungus modifies the host cell boundary very little while the fungal hypha itself apparently is also not modified during the penetration process. No sheath membrane or sheath was observed surrounding the hyphae. The dissolution of starch grains and finally the disintegration of nearly the entire algal cell culminated the infection process.
The effectiveness of resistance genes from wild oats, Avena sterilis, against oat crown rust, Puccinia coronata f. sp. avenue, in Canada in 1969
Authors: Fleischmann George
Published: September 2008

All isolates of oat crown rust, Puccinia coronata f. sp. avenae, identified in Canada in 1969 were inoculated onto 12 different lines containing resistance from wild oats, Avena sterilis, collected in Europe and the Middle East. Lines that contain resistance genes Pc-38 and Pc-39, and wild oat collections CI 8081 and F158, provide effective resistance to nearly every culture of crown rust. Regional differences in the level of virulence of crown rust cultures isolated from eastern and western Canada were observed on lines that contain A. sterilis resistance, with cultures of crown rust isolated from the east being generally less virulent than those from western Canada.
Unusual drought symptoms in Douglas fir
Authors: McMinn R. G. , Funk A.
Published: September 2008

Defoliation of the mid crown of Douglas-fir trees on Vancouver Island followed the hot, dry summer of 1967. Reddening of foliage in a similar mid crown position occurred on other trees in the spring of 1968. The position of these effects could not be attributed to localized fungus infections, insects, or microclimatic influences. A differential response to moisture stress by affected tissues is thought to have caused the unusual patterns. Other effects are also described.