bluuebunny/crossref_metadata_2025 huggingface dataset:
Timing in Chenopodium rubrum of export of the floral stimulus from the cotyledons and its action at the shoot apex
Authors: King R. W.
Published: September 2008

When the cotyledons of 6-day-old seedlings of Chenopodium rubrum were removed at various intervals after exposure to a single 13.5-h dark period, defoliation during the first 6 h after darkness prevented flowering. If the cotyledons remained on the plant for a further 5 or more hours flowering gradually increased. Within 20 h after the end of the dark period, the cotyledons had completed their essential role and subsequent defoliation had no influence on flowering. A cotyledon area of about 30 mm2 was required for maximal floral induction.It can be concluded that a transmissible factor—often termed floral stimulus—was produced in the cotyledons following a short-day exposure. It is also apparent that flowering in Chenopodium rubrum depends on the generation of a floral stimulus in short days, rather than on control by a transmissible inhibitor of flowering produced under long days.After arrival of the floral stimulus at the apex there was a doubling from 2% to 4% in the percentage of cells undergoing mitosis. This increased value of the mitotic index was maintained during floral development and probably reflected an increased rate of cell division. There were rapid and sometimes rhythmic fluctuations in the percentage of dividing cells.
Further observations on cytoplasmic streaming in Chara braunii
Authors: Pickard William F.
Published: September 2008

The cytoplasmic streaming of Chara braunii is investigated and evidence is presented to show:(i) that it is not affected by magnetic fields;(ii) that its cross-sectional variation is that which would be expected if the cytoplasm, tonoplast, and vacuolar sap behaved like a simple, viscous fluid;(iii) that its cessation following an electrical excitation does not depend upon an influx of calcium ions from the medium surrounding the cell.
On the relation between Picea pungens and Picea engelmannii in the Rocky Mountains
Authors: Daubenmire R.
Published: September 2008

Although none of the morphologic characters separating Picea pungens from P. engelmannii is absolute, a hybrid index analysis of 21 populations strongly supports a conclusion that the two species do not hybridize when they occur together in the same habitats. The characters most useful in separating the species are listed, and the geologic history of P. pungens is speculated upon.
Structural positioning and orientational development in the vegetative organs of Poa pratensis with special reference to the rhizome axillary buds
Authors: Fisher John E.
Published: September 2008

The apical meristem of P. pratensis is hemi-ellipsoidal, the plane of bilateral symmetry being readily recognizable. On each side of the apex a prominent pair of tiers of surface cells straddles the line of the plane of symmetry from the upper limit of the active promeristem and extends basipetally into the first and frequently second foliar primordia. Initiation of a new foliar primordium (phytomer) is centered in one or the other of the paired tiers. Occasionally, a single cell in a tier appears to undergo initial mitotic activity. The specific tier of initial activity determines the deviation from symmetry of the whole phytomer including that of the leaf at the top of the phytomer and of the lateral bud at its bottom. The subtending leaf does not determine the deviation from the plane of symmetry of the axillary bud. The first leaf of the axillary bud (not the prophyll) is positioned with its point of origin, hence its midrib, displaced away from the plane of symmetry of the main stem and with its larger semicircumference towards the main stem. Thus the deviation from bilateral symmetry of all the organs of the phytomer and the initial deviation from symmetry of the organs produced by the axillary bud are determined originally by the specific tier of cells in the promeristem of the main shoot that is stimulated into initial activity. This initial orientation of the axillary bud is the first of the many orientations that determines the pathway through the soil that the rhizome will ultimately follow.
Variations and correlations within and between morphology, pathogenicity, and pectolytic enzyme activity in Sclerotinia from Saskatchewan
Authors: Morrall R. A. A. , Duczek L. J. , Sheard J. W.
Published: September 2008

One hundred and fourteen isolates of Sclerotinia from 23 different hosts in many parts of Saskatchewan were grouped, according to their morphology, on minimal medium. Two types of seedling pathogenicity tests on six host species were conducted on at least one isolate from each morphological group and one from each host species. A total of 38 isolates was tested. Assays for pectolytic enzyme activities of the same 38 isolates were done using a defined medium, and Swede turnip and carrot tissue as substrates. Polygalacturonase, pectin transeliminase, and pectin methylesterase were all tested. The results showed that an endopolygalacturonase was probably the most prevalent enzyme. Some isolates also produced exopolygalacturonase and pectin methylesterase, but pectin transeliminase was never detected. There was no correlation between pathogenicity of the isolates and their enzyme activities in vitro or in vivo, suggesting that pectolytic enzymes are not responsible alone for pathogenicity. Agglomerative classification was used to demonstrate relationships between the isolates. However, the isolates did not fall into discrete groups based on morphological, pathological, physiological, or even combined characteristics. Neither were there clear host or geographic associations. This continuous variation rather than a segregated population is consistent with Purdy's "broader concept of the species S. sclerotiorum."
Studies in the Arundinelleae (Gramineae). XI. Taximetrics of changing classifications
Authors: Phipps J. B.
Published: September 2008

By listing all the species of Arundinelleae known in 1860, 1930, and 1937 and conducting taximetric studies on each of these sets the author is able to demonstrate that "inaccuracies" of classification, by present-day standards, were primarily due to poor taxonomy and not due to the low density of species known in the past. By the same token, the arguments about generic delimitation of the past 35 years are largely due to inherent taxonomic problems rather than poor systematics.
Influence du fluor sur le Funaria hygrometrica et l’Hypogymnia physodes
Authors: Comeau Gilberte , LeBlanc Fabius
Published: September 2008

We fumigated plants of Funaria hygrometrica and Hypogymnia physodes with 13, 65, and 130 parts per billion (ppb) of hydrofluoric acid for 4, 8, and 12 h and then 13 ppb for 36, 72, and 108 h. We examined the macroscopic and microscopic changes, the quantity of fluoride absorbed, and the capacity of these plants to recuperate 3 weeks after fumigation. Results show that at concentrations of 65 ppb/12 h the moss and the lichen show chlorotic spots and already some chloroplasts start to disintegrate and plasmolysis occurs. After 3 weeks of recuperation the Funaria had lost between 26 and 36% and the Hypogymnia between 36 and 47% of the fluoride accumulated.
Genera coelomycetarum. V. Alpakesa and Bartalinia
Authors: Morgan-Jones G. , Raj T. R. Nag , Kendrick Bryce
Published: September 2008

The type species of Alpakesa Subramanian and Ramakrishnan, A. yuccaefolia (Hall) Subramanian and Ramakrishnan is redescribed and illustrated. Two additional species, A. uniseptata sp. nov., and A. nolinae (Pollack) comb. nov. (≡ Bartalinia nolinae Pollack), are placed in the genus. The generic diagnosis is emended accordingly. The two original species of Bartalinia Tassi, B. robillardoides Tassi and B. nervisequa Tassi, are considered conspecific. The genus is redescribed and illustrated.
Growth kinetics of Marquis wheat. II. Carbon dioxide dependence
Authors: Macdowall F. D. H.
Published: September 2008

Marquis wheat was grown in growth rooms with four different concentrations of carbon dioxide and four to seven different intensities of light in a 16-h photoperiod at 25 °C. Growth was expressed quantitatively as the pseudo-first-order rate coefficient. Carbon dioxide stimulated growth, but the effect was greater the lower the light intensity in opposition to the known effect on photosynthesis. Carbon dioxide and light, in effect, did not influence the "rate" of growth of wheat additively but, rather, mutually compensated over a wide range. The growth coefficient of the roots was a little less than that of the shoots at all carbon dioxide concentrations and light intensities, probably owing to the cost of translocation. However, root growth benefited most from carbon dioxide enrichment at low light intensities. At intermediate light intensity there appeared to be a carbon dioxide concentration optimal for shoot growth. Carbon dioxide enrichment did not influence the maximum growth coefficient of Marquis wheat with respect to light intensity. The light-using efficiency of growth, calculated for vanishingly low light intensity at which it is maximal, was maximal for shoots at 1300 ppm CO2 but that for laminal area and root dry weight increased with CO2 to 2200 ppm at which the value for "leaves" was nearly fourfold that for roots. Unlike photosynthesis, the stimulation of growth by raised CO2 concentration was accomplished by increased efficiency of, and not capacity for, the net photosynthetic use of light.
Sterols in relation to ability of Pythium sylvaticum to survive in soil
Authors: Kaosiri Thawee , Hendrix James W.
Published: September 2008

The influence of sterol nutrition on the subsequent ability of Pythium sylvaticum to survive in soil was investigated. Cultures grown on hempseed decoction produced more propagules detectable after incubation in soil than cultures on synthetic glucose – glutamic acid media. The presence of cholesterol in the synthetic medium resulted in more soil-borne propagules than occurred with sterol-free medium, but cultures grown without sterol survived in soil for at least 24 weeks. Propagules produced by sterol-free cultures survived in soil as well as those produced on hempseed decoction or synthetic medium containing cholesterol. Mated cultures produced fewer soil-borne propagules than single cultures of the same isolates. Propagules, regardless of the nutrition of the originating cultures, survived 28 days incubation in soil at −20, 3, 24, and 30C. Sterols appear influential in affecting the number and kind of propagules produced, but not their quality as determined by ability to survive in soil.
Reductive amination in soybean cotyledons: a survey of aminating dehydrogenases
Authors: Wu W. Yung-Fan , King J.
Published: September 2008

Crude enzyme extracts from green, 11-day-old soybean (Glycine max L. var. Canadian No. 1) cotyledons were examined for aminating dehydrogenase activity. Apparent reductive amination of α-ketoisocaproate, α-ketoisovalerate, pyruvate, and β-hydroxypyruvate observed as an increase of NADH oxidation when either NH4Cl or (NH4)2SO4 was added to reaction mixtures could not be confirmed by paper cochromatography with appropriate authentic amino acids. Increase in NADH oxidation was explained by increases in activity of either non-aminating dehydrogenases or NADH oxidase caused either by a shift in pH when NH4+ was added to assay mixtures or by added Cl− and SO42−. Negative results were also obtained with glyoxylate. Reductive amination was confirmed only with α-ketoglutarate.
The effect of gibberellic acid on buckwheat flowers
Authors: Nozzolillo Constance
Published: September 2008

Two-week-old buckwheat seedlings growing under a 16-h day were treated with gibberellic acid. Subsequent flower bud initiation was unaffected, but fewer buds were formed. Flowers were morphologically normal except that pistils were much reduced in size. Fruit production was greatly reduced in the treated plants, although height growth and dry weight were slightly increased.
Vestigium, a new genus of Coelomycetes
Authors: Pirozynski K. A. , Shoemaker R. A.
Published: September 2008

Vestigium, a new genus of acervular, staurosporous Coelomycetes is proposed for V. felicis, a new species occurring on Thuja in the Pacific Northwest.
Ontogeny and histochemistry of the vegetative apex of Cosmos bipinnatus "Sensation"
Authors: Molder Marje , Owens John N.
Published: September 2008

Plants of Cosmos bipinnatus Cav. "Sensation" (a quantitative short-day plant) were grown under continuous conditions of long days to maintain the vegetative state. The vegetative apex shows a cytohistological zonation pattern superimposed upon a tunica–corpus organization. The biseriate tunica is separated into two zones: axial and lateral; while the corpus is separated into three zones: the peripheral, central, and rib meristem. Based on mitotic activity (both frequency and index) there is neither a "méristème d'attente" nor an "anneau initial" present. A double plastochron cycle is present because of the decussate leaf arrangement and the presence of prominent leaf bases. Cytohistological zonation, nucleolar volume, RNA content, and mitotic index vary in a cyclic manner with the phase of plastochron. Although the degree of zonation decreases just after leaf buttress initiation, zonation does not disappear at any time during a plastochron.
Regulation of invertase activity and growth in rice (Oryza) coleoptile sections by gibberellic acid and sucrose
Authors: Soni Sarvjit L. , Kaufman Peter B.
Published: September 2008

Changes in invertase activity and growth were examined in excised rice coleoptile sections which were treated with water, gibberellic acid (GA3), sucrose, and GA3 + sucrose. Invertase activity with all treatments rises in parallel during the first 6 h. Between 6 and 12 h, the GA3 and GA3 + sucrose treatment causes the invertase activity to increase at a faster rate than the respective water and sucrose controls. For all treatments, the peak invertase activity occurs at 12 h; it then declines rapidly between 12 and 24 h. After this, the enzyme activity becomes stable by 36 h for sucrose and GA3 + sucrose treatments. In contrast, in water and GA3 treatments, the enzyme activity continues to decrease up to 48 h, then attains a steady state level. With water, GA3, sucrose, and GA3 + sucrose, there is a close correlation between the time of maximal invertase activity and the time of maximal growth rate (12 h), and the kinetics for promotion of both processes are essentially the same. This study indicates that both GA3 and sucrose may be involved in regulating levels of invertase and that invertase activity is closely associated with growth in rice coleoptile sections.
La tourbière à sphaignes Mer Bleue près d'Ottawa. II. Quelques facteurs écologiques
Authors: Joyal Robert
Published: September 2008

Mer Bleue is an ombrotrophic sphagnum and black spruce bog near Ottawa, Ontario. Its 5000 ac offer a vegetation composed of 10 associations and 3 subassociations. Day temperature in the bog is 2.7°F higher and night temperature 3.2°F lower than at Uplands Airport 7 mi away. Relative humidity is also higher. The black spruce stand is the most humid and the coolest of all plant associations and its water table is the highest, while Polytrichum association is the dryest and the warmest. Black spruce stands also have the most stable climate.Temperature at 1 ft depth in the peat moss reaches a minimum of 55°F in summer. At 2 ft depth a maximum of 47°F occurs in September and a minimum of 24°F in February. The pH lies between 3.8 in ombrotrophic areas and 6.5 in minerotrophic conditions. Many other aspects are discussed.
A new species of Phellodon possessing clamp connections
Authors: Harrison Kenneth A.
Published: September 2008

The finding of clamps throughout the tissues in Phellodon fibulatus sp. nov. raises a question as to the recognition of the family Bankeraceae, characterized mainly by hyaline echinulate spores and a distinctive odor when dried. Grand and Moore have shown that the ornamentation on the spores of Phellodon is the same as in Hydnellum and Hydnum, and Brady reports the presence of the thelephoric acid in the same genera. This leaves hyaline spores as the only significant difference between Hydnellum and Phellodon. Odor of the dried specimens is considered to be of doubtful value as a family character. It is concluded that the family Bankeraceae is superfluous, and its genera are referred to the Hydnaceae.
Microevolution of the photosynthetic temperature optimum in relation to the elevational complex gradient
Authors: Fryer John H. , Ledig F. Thomas
Published: September 2008

Balsam fir seedlings were grown under uniform conditions from seed collected along an elevational gradient in the White Mountains of New Hampshire. Photosynthetic temperature optimum of the seedlings decreased with increasing elevation of the seed source. The change in temperature optimum with elevation was similar to the adiabatic lapse rate, suggesting a precise adaptation to temperature through natural selection.
Action inhibitrice des morphactines sur l'axe principal des Coleus
Authors: Dubuc-Lebreux Michèle-A.
Published: September 2008

Specimens of Coleus hybridus 'Chartreuse' have been treated with two morphactins (IT 3233 and IT 3456) which were applied, either one or four times, to the apex of the plant or the soil beneath, at 25 or 50 ppm. The treated plants have shown inhibition symptoms in their growth at the principal axis. Generally the action of IT 3233 was minimal; on the other hand, IT 3456 has brought a well-marked reduction of the length of the axes. A factorial analysis of the measurements of the treated groups by IT 3456 has permitted the determination of two very significant factors: 'method of application' and 'frequency'; also it has shown a significant interaction between these factors. The two concentrations used did not produce effects that were significantly different.
Occurrence and significance of fungi inhabiting galls caused by Peridermium harknessii
Authors: Byler J. W. , Cobb Jr. F. W. , Parmeter Jr. J. R.
Published: September 2008

Many fungi were associated with Peridermium harknessii galls on pines growing on or near the California coast. Included were saprophytes in dead gall tissues, mycoparasites on rust aeciospores, and secondary fungus parasites of rusted tissues. Gibberella lateritium, Nectria fuckeliana, and Diplodia pinea were secondary fungi that sometimes partially or completely killed the galls. Information regarding the identification, genetics, infection courts, and distribution of these fungi is given.
Metabolic rates for major nutrients in suspension cultures of plant cells
Authors: Rose Dyson , Martin S. M. , Clay P. P. F.
Published: September 2008

Well-habituated cells, which had been initiated from root tissue of Ipomoea sp. and kept in suspension culture for more than 2 years, were grown in 14-liter stirred-jar fermenters in complex media containing casein hydrolysate. Samples were taken at 12-h intervals, and both cells and media analyzed for major constituents. Polynomial functions of time were fitted, by least squares, to these data, and the rate of disappearance or accumulation (medium and cells, respectively) of the major components was calculated by dividing the first derivative of these functions by the corresponding dry cell weight. The results indicate that growth of these cultures involved a sequence of activities such that the culture as a whole, during the period of rapid increase in cell yield, progressed from one containing predominantly dividing cells with a high rate of nitrogen anabolism to one containing predominantly "maturing" cells with a proportionately higher rate of carbohydrate anabolism. Increasing the nitrogen content of the medium affected the metabolic rates and the apparent net growth rate to only a minor extent, but did alter cell composition.
Metabolism of soluble carbohydrates in Acetabularia mediterranea cells
Authors: Smestad Berit , Percival Elizabeth , Bidwell R. G. S.
Published: September 2008

Cells of Acetabularia mediterranea (pre-cap, with caps, or caps only) were exposed to 14CO2 in seawater, then transferred to unlabeled medium and allowed to metabolize in light or darkness for 2–3 h. Sucrose is the main low-molecular weight product of photosynthesis. It is used in the synthesis of a homologous series of inulin-type polysaccharides, each of which is used for the formation of the next higher homolog. Glucose resulting from sucrose metabolism is reutilized, but fructose which arises from sucrose hydrolysis is stored as such, and does not undergo further metabolism during the period of these experiments.
Interaction between fungi in wood blocks
Authors: Hulme M. A. , Shields J. K.
Published: September 2008

The decaying ability of Polyporus versicolor, Polyporus hirsutus, Polyporus adustus, and two Peniophora spp. was tested in small blocks of either hardwood or softwood in which selected xylophilous fungi had been allowed to develop as the primary saprophyte. The xylophilous fungi used were Scytalidium lignicola, Paecilomyces varioti, Trichoderma viride, Gliocladium viride, Hypocrea gelatinosa, a Penicillium sp., and C134 (Mycelia sterilia). All except H. gelatinosa could inhibit decay by the five wood-rotting fungi provided that the blocks were not autoclaved between inoculations. The results are interpreted mainly in terms of an early depletion of more accessible nutrients by the primary saprophyte, hindering the normally rapid process of colonization by secondary fungi.
Sensitization of Aspergillus flavus spores to gamma radiation by halogens
Authors: Mohyuddin Mirza , Skoropad W. P.
Published: September 2008

Survival curves for spores of Aspergillus flavus Link var. columnaris Raper and Fennell were obtained after their irradiation with gamma rays in the presence of Na+, K+, and Ca2+ halogens. Halogens of Na+ and K+ sensitized the spores to the radiation and enhanced sensitization occurred as the dose of radiation was increased. Halogens of Ca2+ protected the spores against a radiation dose of 25 krad but at higher doses although CaCl2 was protective, CaBr2 and CaI2 were radiosensitizers, with CaI2 the most efficient radiosensitizer.
Development of stromata and the imperfect state of Eutypella parasitica in maple
Authors: Kliejunas John T. , Kuntz James E.
Published: September 2008

Effused and isolated stromata of Eutypella parasitica were delimited by zone lines and contained ascogonial coils intermixed with mature perithecia throughout the year. The imperfect state was associated with perithecia in red maple and Norway maple bark but was not found in sugar maple bark. Conidial pustules were closed or variously opened labyrinthiform structures without a distinct wall and contained conidia 24–29 × 1–1.5 μ. The imperfect state was characteristic of both the form-genus Cytosporina and the form-genus Libertella.
Additions to the autoecious species of Puccinia on Heliantheae in North America
Authors: Parmelee J. A.
Published: September 2008

Observations on eight autoecious species of Puccinia on Heliantheae provide distributional extensions and additions to life cycles.
Abscission and dehiscence in the squirting cucumber, Ecballium elaterium. Regulation by ethylene
Authors: Jackson Michael B. , Morrow Ielene B. , Osborne Daphne J.
Published: September 2008

When treated with ethylene, mature fruits of the squirting cucumber (Ecballium elaterium (L.) A. Rich) abscind and dehisce prematurely. Abscission of male flowers is also accelerated by ethylene. Visible signs of senescence, a rise in ethylene production, and reduced carbon dioxide production always precede abscission or dehiscence in untreated fruits and flowers. The amounts of diffusible cellulase increase in tissues on both sides of the fruit abscission zone after exposure to ethylene. Anatomical features of this abscission zone are described.The leaves of Ecballium do not abscind although the blade and petiole produce large amounts of ethylene at senescence, nor do they separate when ethylene is supplied. Ethylene treatment of attached fruit peduncles accelerates their rate of elongation in the growing zone below the apical hook. The regulation of growth and abscission in these organs is discussed.
Inhibition of tobacco mosaic virus infection by plant extracts
Authors: Apablaza G. E. , Bernier C. C.
Published: September 2008

Leaf extracts of pepper, geranium, and jimsonweed inhibited the development of local lesions induced by tobacco mosaic virus (TMV) on Pinto bean leaves when mixed with the inoculum; sprayed on the underside of the leaf before inoculation of the upper surface; or sprayed on the upper leaf surface after inoculation. The extracts also inhibited lesion development on the primary leaf opposite to the one on which they were applied. The inhibitory activity of the geranium and pepper extracts was separated into two fractions; one with a molecular weight greater than 50 000 and one with a molecular weight range of 1000–50 000. The inhibitory activity of the jimsonweed extract was present in the high molecular weight fraction only. The high molecular weight fraction from pepper was inhibitory when applied to the underside of the leaf. This evidence, and that supplied by the jimsonweed extract, indicates that high molecular weight fractions are capable of inducing a systemic resistance even when applied to uninjured tissue.
Changes in soluble proteins of cinnamon fern leaves during development
Authors: Caponetti James D. , Harvey William H. , DeMaggio A. E.
Published: September 2008

The complement of soluble proteins contained in the five annual leaf sets and the apical region of the shoot of cinnamon fern, Osmunda cinnamomea L., has been determined using disc electrophoresis. The apical region and the very young leaf primordia contained high and comparable numbers of soluble proteins. Older primordia and mature leaves contained progressively fewer soluble proteins, except that the number of proteins increased in the oldest sets of leaves. These findings are discussed in relation to the results reported for the leaves of some flowering plants.
Ultrastructural changes in rust-infected tissues of flax and sunflower
Authors: Coffey Michael D. , Palevitz Barry A. , Allen Paul J.
Published: September 2008

Similar changes occurred in the ultrastructure of host cell organelles in the rust-infected tissues of both flax and sunflower. Up to the onset of sporulation at 8 days after inoculation the only major alteration in cell structure was a marked tendency for the cell organelles to be aggregated around the intracellular fungal haustorium and an accumulation of starch in the plastids. During sporulation, however, some striking changes occurred in the structure of plastids, mitochondria, and microbodies. Eleven days after inoculation, in a zone of host tissue adjacent to the rust pustule, the plastids no longer contained starch and varied in structure even within a single cell. Some were similar to normal chloroplasts, others had larger grana, and some bore a close resemblance to chromoplasts. In sunflower, but not in flax, mitochondria contained atypical plate-like cristae in addition to the usual vesiculate type. The micro-bodies of both plant species all contained crystalline cores in contrast to earlier stages in the disease where crystals were only occasionally detected. The plastids were also altered considerably in another zone of tissue situated beneath the rust pustule. In some plastids the thylakoids extended along their long axis, forming several large grana, and in others the large grana were interconnected by lamellae arranged in a vesicular or tubular configuration. Frequently the starch grains in these plastids were broken down into small rosettes of darkly staining particles with an appearance similar to that of animal glycogen.
Cellular slime molds in forest soils of eastern Canada
Authors: Cavender James C.
Published: September 2008

The occurrence and distribution of cellular slime molds in eastern Canada were investigated. Particular attention was given to boreal forest since there is no previous study of Acrasieae in soils of this forest formation. Four species, Dictyostelium mucoroides, D. minutum, Polysphondylium pallidum, and P. violaceum, are common in spruce–fir forest soils. Of these only D. mucoroides and D. minutum are constant and dominant. Numbers per unit of soil averaged higher than in other forest soil habitats investigated during the course of the author's researches. The relatively high densities, up to ca. 20 000/g, were limited to certain sites within a forest, probably where abundant bacteria exist, although this was not determined. Occasionally D. discoideum, D. lacteum, and Acytostelium leptosomum can also be found in the boreal forest region. Two other species, D. purpureum and D. polycephalum, were found only in deciduous forest. The distribution of Acrasieae probably extends well beyond the boreal forest proper into the hemiarctic of tundra–forest patches.
Studies on sunflower rust. IX. Application of thin-layer chromatography to a study of variation in Puccinia helianthi
Authors: Hennessy C. M. R. , Grant W. F. , Sackston W. E.
Published: September 2008

Chromatograms of methanol extracts of rust-infected sunflower leaves were characterized by two phenolic compounds which fluoresced bright blue in ultraviolet light. One of these was considered to be a non-specific metabolite of necrotic tissue; the other, which was unstable and could not be identified, appeared to be a product of compatible host–parasite interactions on Helianthus annuus. Races of Puccinia helianthi were not distinguishable by their phenolic constituents. Extracts of sunflower leaves infected with Erysiphe cichoracearum, Sclerotium bataticola, and Verticillium dahliae also showed fluorescent spots which were more or less specific. A single spot distinguished a virulent isolate N of S. bataticola from an avirulent isolate E.
Indoleacetic acid stimulation of phosphorylation and bicarbonate fixation by chloroplast preparations in light
Authors: Tamàs Imre A. , Atkins Brian D. , Ware Susette M. , Bidwell R. G. S.
Published: September 2008

The rate of phosphorylation in illuminated chloroplast preparations from spinach, Swiss chard, or Acetabularia mediterranea was increased by physiological concentrations of indoleacetic acid (IAA), optimum effect being obtained at 10−7 M. Treated chloroplasts gave an increased P/2e ratio, suggesting a greater degree of coupling between electron transport and ATP synthesis. Five minutes after incubation the effect of the hormone was already noticeable. During prolonged illumination the effect of IAA was greatly magnified, raising the phosphorylation rate more than threefold over the control rate. Stimulation of 14C-bicarbonate fixation was also observed in the presence of the same levels of IAA.
Electrical impedance studies of stem tissue of Solanum clones during cooling
Authors: Hayden R. E. , Dionne L. , Fensom D. S.
Published: September 2008

Specific electrical impedance measurements made on the stems or petioles of four varieties of Solanum were found to discriminate various clones when the plants were grown and tested under carefully controlled conditions. Frost hardiness of clones was related to the depression of the freezing point in the absence of supercooling, to the specific resistance at 4.4 °C, to the slope of the log impedance – temperature cooling curves, and to the position of the temperature recovery curve after chilling. The technique appears to be potentially useful for selection of frost resistant clones in breeding for this property.
Taxonomy and distribution of Atriplex species in Nova Scotia
Authors: Taschereau P. M.
Published: September 2008

A biosystematic study of the genus Atriplex, based on field, herbarium, culture, and cytological work delineates the taxa of this genus occurring in Nova Scotia. The study gives detailed morphological descriptions of eight species, and reports their chromosome numbers, breeding systems, ecology, and distribution. Atriplex patula L., A. hastata L., A. littoralis L., and A. glabriuscula Edmondston, considered as varieties of A. patula by recent North American authors, are given specific rank. The name Atriplex hastata L. is found to be misapplied. The correct name for this taxon is Atriplex triangularis Willdenow. Two new species—Atriplex acadiensis, a tetraploid, and A. Franktonii, a diploid—are described. A hexaploid species, A. subspicata (Nutt.) Rydb., not previously recognized from eastern North America, is reported. M. L. Fernald's report of A. patula var. bracteata Westerlund from Nova Scotia is shown to be based on an incorrect determination. Atriplex glabriuscula var. oblanceolata Vict. & Rousseau, and A. patula var. bracteata Westerlund are relegated to synonymy.
Seasonal variation in the composition of the volatile oil of the leaves, buds, and twigs of white spruce (Picea glauca)
Authors: Rudloff E. von
Published: September 2008

Gas chromatographic analysis of the volatile terpenes of the leaves, buds, and twigs of white spruce has confirmed that major changes take place only in the new shoots during the early part of summer. Minor changes were recorded for the older shoots during the same period. The relative amounts of β-pinene, limonene, and myrcene in the volatile oil of the buds change significantly during fall and winter. In contrast, the volatile oil of the leaves and twigs remains constant in quantitative composition during late summer, fall, and winter. The sequence in which the relative amounts of each terpene are laid down in the new growth is complex and no correlation with accepted biosynthetic pathways for monoterpenes could be found. During May substantial amounts of sesquiterpenes are present in the new growth, but these appear to be metabolized further as the summer progresses. The implications for chemosystematic studies are discussed.
Genera coelomycetarum. VI. Kellermania
Authors: Morgan-Jones G. , Raj T. R. Nag , Kendrick Bryce
Published: September 2008

Two additions are made to the genus Kellermania Ell. and Everh., K. attenuata sp. nov. and K. multiseptata sp. nov. The generic diagnosis is emended accordingly. Kellermania yuccaegena Ell. and Everh., the type species, and K. major Dearn. and Barth., are also redescribed and illustrated. A key is provided.
Five new species of Podospora from East Africa
Authors: Khan Rahmet Shah , Cain R. F.
Published: September 2008

The following new coprophilous species are described: Podospora caligata found on cow dung from Tanzania, P.papillata on elephant and zebra dung from Kenya, P. deropodalis on zebra dung from Kenya, P. spinulosa on cow, elephant, and zebra dung from Kenya and Tanzania, and P. multispora on cow dung from Kenya. These species have been developed in moist chambers at room temperature in the Department of Botany, University of Toronto. The genus Podospora Cesati is restricted to species in which the ascospores have an apical, circular germ pore, a hyaline basal cell, and hyaline gelatinous appendages. These appendages have been studied under phase-contrast microscope and in India ink mounts.
Changements dans les lipides de la luzerne en conditions menant à l'endurcissement au froid
Authors: Grenier G. , Trémolières A. , Therrien H. P. , Willemot C.
Published: September 2008

The lipids of alfalfa were analyzed during artificial hardening. An increase in fatty acids, particularly linoleic acid; phospholipids; and triglycerides was observed in leaves, stems, and roots. The largest increase in phospholipids, rich in linoleic acid, occurred in the roots. The desaturation of the fatty acids was increased; this increase in desaturation was slight in the phospholipids, but pronounced in the triglycerides. The galactolipids were apparently not affected by the treatment. The level of trans-3-hexadecenoic acid, which is present only in phosphatidyl glycerol, was markedly depressed during hardening.
Some features of vegetative and sexual reproduction in Endomyces species
Authors: Rij N. J. W. Kreger - Van , Veenhuis M.
Published: September 2008

Vegetative reproduction and, as far as possible, sexual reproduction have been studied by light and electron microscopy in six Endomyces species. In most of these species multiple scars were observed on the arthrospores as a result of repeated germination from the same site. Plasmodesmata in the septa of Endomyces decipiens, E. reessii, and E. geotrichum were arranged at random, while those of E. magnusii, E. ovetensis, and E. tetrasperma appeared in a circle. For all species, except E. decipiens, gametangiogamy preceding ascus formation has been described. Mature ascospores in E. ovetensis and E. tetrasperma have a wide, regular, smooth wall and are dehisced. Ascospores of E. reessii and E. geotrichum are not liberated from the ascus and have a lobed, punctate wall. In E. geotrichum the lobes are arranged in such a way that a groove runs around the spore.
Development of haustoria of Melampsora lini
Authors: Littlefield Larry J.
Published: September 2008

An initial step in haustorium formation is the contact of a terminal intercellular mycelial cell with the wall of a host cell. The former differentiates to form a haustorial mother cell having a thickened wall in the region of contact. A penetration peg develops in the thickened region of the cell wall; it elongates, penetrates the host cell wall, and extends into the lumen of the host cell. A dark-staining region, the neck ring, develops in the wall of the penetration peg and persists throughout subsequent stages of development. The distal end of the penetration peg expands to form a somewhat spherical haustorial body. Subsequently, one to several lobes form on, and extend from, the body of the haustorium. The more ephemeral stages of development are the initiation of the spherical haustorial body and the elongation of the penetration peg. The less ephemeral stages are prepenetration and early postpenetration of the host cell wall and the intermediate stages of haustorial expansion.
Pectolytic enzyme production by Phoma betae
Authors: Bugbee William M.
Published: September 2008

Phoma betae from decayed sugar beet storage root tissue grew most rapidly in culture at 15C but produced more polygalacturonase (PG) at 20C. When the fungus was supplied with six different nitrogen sources, it produced the most PG on (NH4)2SO4.Assays of dialyzed culture filtrates using sodium polypectate and pectin or cell wall material from storage roots as the carbon sources showed the production of exopolygalacturonase (exo-PG) and endopolygalacturonate trans-eliminase (endo-PGTE). No pectin methyl esterase was detected. Exo-PG and endo-PGTE also were present in decayed sugar beet tissue. Only endo-PGTE was detected within 3 mm of tissue surrounding the rotted area.In culture, cell wall material from the susceptible variety A58 induced more endo-PGTE formation than the resistant 2B. But 2B induced more exo-PG formation than A58. It is suggested that endo-PGTE plays a major role in cell wall degradation because pH 7.5 was optimum for tissue maceration and pH 8.5 for enzyme activity and the advancing margins of rotted tissue contained only endo-PGTE.
The radiation balance of an apple tree
Authors: Proctor J. T. A. , Kyle W. J. , Davies J. A.
Published: September 2008

Measurements of radiation balance components over an apple tree on 7 days during the growing season showed that 17% of the short-wave radiation was reflected, 17% was lost as long-wave radiation and net radiation amounted to 66%. The reflection coefficient exhibited a characteristic diurnal variation, demonstrating its dependence on solar zenith angle, and varied little over the season. Within the orchard, surfaces ranked in order of increasing reflection coefficient as tree, dry orchard grass, and intertree space.Correlation coefficients relating hourly values of net radiation to incoming short-wave radiation and net short-wave radiation, and net long-wave radiation to net short-wave radiation were highly significant. The heating coefficient was positive and decreased slightly at the end of the season. The long-wave exchange coefficient was negative and exhibited no seasonal trend. This coefficient was closely correlated with screen temperature and may provide a basis for interpretation of surface radiative processes.
Autogamy, allogamy, and pollination in some Canadian weeds
Authors: Mulligan Gerald A.
Published: September 2008

This paper is concerned with insect visitors to some Canadian weeds. It shows that both self-pollinating (autogamous) and cross-pollinating (allogamous) weeds are visited during the flowering period. It was found that self-incompatible species were visited by insects frequently, whereas self-compatible weeds were not visited or were rarely visited. The self-compatible group showed some difference, in that autogamous annual and winter annual weeds were visited less than were autogamous biennial and short-lived perennial weeds. Most of the insect visitors, to both the autogamous and allogamous species of weeds, were native species, whereas the weeds themselves were mostly introduced species. The insects, also, evidently visited more than a single species of plant over a short period of time. The implications of the insect visits to the genetic structure of the plants and their colonizing abilities are then briefly discussed.
Isolation and culture of monokaryotic haplonts of Ustilago tritici, observations on their physiology, and the taxonomic relationship between U. tritici and U. nuda
Authors: Nielsen J.
Published: September 2008

Spores of Ustilago tritici were germinated on a medium containing benzoic acid, which induces the formation of dikaryons and inhibits mitosis. After removal of benzoic acid from the medium, mitosis occurred and the four monokaryotic haplonts formed by one spore were isolated by microsurgery. Both mating types grow readily on a minimal medium, in contrast to U. nuda, whose mating type a is proline-deficient. This fundamental physiological difference, supported by previously known morphological differences, was used as evidence to retain U. tritici (loose smut of wheat) and U. nuda (loose smut of barley) as separate species.
Some changes in red maple, Acer rubrum, tissues within 34 days after wounding in July
Authors: Rier John P. , Shigo Alex L.
Published: September 2008

Fluorescence microscopy was used to show that during 34 days after the wounding of red maple, Acer rubrum, callose accumulated in the phloem, new xylary tissues formed, and plugs formed in vessels to 10 cm above and below the wounds.
Mitosis in Mougeotia sp.
Authors: Bech-Hansen Carla W. , Fowke Larry C.
Published: September 2008

Combined light and electron microscope observations have provided new information concerning mitosis in Mougeotia. The distribution of microtubules during division suggests that intact wall microtubules moved at preprophase to form the spindle and returned to the cell wall at telophase. During metaphase and early anaphase, chromosomal microtubules were attached to distinct kinetochores; few interzonal microtubules were evident. The subsequent elongation of the spindle at late anaphase was accompanied by the appearance of numerous interzonal microtubules and the loss of the original nuclear envelope. The nucleoli dispersed during prophase and reformed at telophase. The wall septum appeared at prophase but extended only a short distance into the cell by telophase; microtubules were not associated with the developing septum.
Formation of adventive embryos from rhizoidal filaments in sporelings of four species of Fucus (Phaeophyceae)
Authors: McLachlan J. , Chen L. C.-M.
Published: September 2008

In culture adventive embryos were initiated from secondary rhizoidal filaments of sporelings of Fucus distichus subsp. distichus, F. edentatus, F. serratus, and F. vesiculosus. This was not a response to wounding, but seemed to appear spontaneously under various conditions of temperature, light, and nutrition. Only in subsp. distichus did the parent sporeling and its embryos grow significantly, and thereby contribute to the bushy habit of this species. Attempts to grow detached rhizoidal filaments in culture were unsuccessful, but excision of filaments stimulated formation of adventive embryos.
The culture of Porphyra linearis (Bangiales, Rhodophyceae)
Authors: Bird C. J. , Chen L. C.-M. , McLachlan J.
Published: September 2008

The life cycle of Porphyra linearis Grev. has been completed in culture to five generations. Conchosporangia formed at 5–20 °C but release of conchospores began only at the critical temperature of 13 °C, and continued at a slower rate at 5 °C. Conchocelis, the perennating phase, was long-lived despite continuous sporulation and attrition. Leafy thalli sporulated readily but seldom exceeded 4–5 cm in length. β-Spores always formed before α-spores, and both types of spore frequently occurred on a single plant. Neutral spores were not observed. Variation in ability to shed conchospores indicates the existence of strains of conchocelis.
Development of cultured barley embryos. II. Precocious germination and dormancy
Authors: Norstog Knut , Klein Richard M.
Published: September 2008

Precocious germination was suppressed in cultured barley embryos by reduced O2, higher temperatures, elevated sucrose concentrations, and light. These parameters appear interrelated in that change in one may be offset partly by changes in others. Red light suppressed precocious germination, while far-red and blue did not. Seasonal differences in precocious germination responses were noted. Embryos excised from greenhouse plants in January tended to be dormant, those from plants grown in "warm-day" growth chambers, or those excised from field-grown plants in July, did not. It is thought that precocious germination in barley reflects the absence of dormancy factors which may be present in some embryos at an early stage in their development, and that dormancy in this sense does not imply quiescence since embryogenesis may continue.
Inhibition by abscisic acid of the light and dark uptake of potassium by slices of Vicia faba leaves
Authors: Horton Roger F. , Bruce K. R.
Published: September 2008

Abscisic acid at a concentration of 10 mg/liter inhibits up to 79% of the potassium uptake of slices of expanding Vicia faba leaves in the dark, and up to 75% of the greater potassium influx occurring in the light. Abscisic acid has no effect on the potassium influx into tissue from non-expanding, mature leaves which consistently leak potassium into the media. The possible role of abscisic acid in ion movement within plant tissue is discussed.
Energy relationships and dicamba transport in petiole segments
Authors: Chang F. Y. , Born W. H. Vanden
Published: September 2008

Transport of 2-methoxy-3,6-dichlorobenzoic acid (dicamba-14C) in petiole segments from Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) plants kept in the dark for 24 h was basipolar and dicamba was not metabolized. The velocity of transport in the petiole segments was 0.8 mm/h. Degree of polarity of transport of dicamba was dependent on segment length and temperature. ATP promoted and DNP (2,4-dinitrophenol) decreased polar transport of dicamba. Exposure of the plants to light before the experiment increased subsequent uptake and retention of dicamba by the petiole segments, but transport into receivers was reduced. Sucrose also increased dicamba uptake and retention. The results indicate that metabolic processes are involved in the uptake, retention, and transport of dicamba by the tissue segments.