bluuebunny/crossref_metadata_2025 huggingface dataset:
Redox currents associated with ion mobility in stems of plants
Authors: Levengood W. C.
Published: September 2008

In vivo investigations of bioelectric currents associated with growth, tissue metabolism, and water responses in the stems of trees and herbaceous plants are described. This experimentation is based on a new technique which allows the continuous monitoring of variations in bioelectric currents related to intertissue redox conditions. Exploratory studies indicate relationships between variations in the redox current and turgor conditions in plants. A correlation between the bioelectric current and the difference in oxidation potentials between the plant and ground electrodes is discussed.In field studies, the current was monitored in different species of trees over a 1-year interval. Similarities in current variations occurred in similar species of trees and were examined in relation to temperature, rainfall, and phenological factors. The current level, examined in trees as a function of radial depth, disclosed the maximum output in the cambium layer. In a study of diurnal variations, a temporal shift in a current maximum was noted along the tree bole.
Limitation of infection by Erysiphe graminis f. sp. hordei culture CR3 by the Algerian gene M1a in barley
Authors: McKeen W. E. , Bhattacharya P. K.
Published: September 2008

Infection of near-isogenic susceptible and resistant (Algerian M1a) barley with Erysiphe graminis f. sp. hordei culture CR3 was studied with the aid of the light and electron microscope. Barley coleoptiles were used extensively because mildew conidia, appressoria, haustoria, and mycelium were more readily found and observed on the non-pigmented two- to four- layered coleoptiles than on leaves. About 80% of the germinated conidia produced haustoria in the susceptible line. Electron micrographs revealed that, in the infections attempted in the resistant line (73%), the penetration peg passed through the barley epidermal wall but grew little further into an aggregation of the host cytoplasm and (or) reaction products which occurred also in the cell of the susceptible coleoptile. Interaction between the host and fungus must have been very rapid because the infection peg had developed to the same extent as one in a susceptible host about 11 h after inoculation. In the 14% of the germinated conidia that penetrated the resistant host successfully, the haustorium developed fully and secondary mycelium was formed but no conidiophores were produced. By the fourth day, fungus growth was greatly retarded. From the fifth day onwards, growth ceased and the colony showed signs of shrivelling and death. Two types of resistance occur, one which is effective during or immediately after host wall penetration, and another which is effective 2–4 days later.
Lattice bodies and filament bundles in apothecial cells of the fungus Ascobolus
Authors: Zachariah K.
Published: September 2008

Electron microscopy of non-sporogenous cells of the apothecium of Ascobolus has revealed the presence in the cytoplasm of numerous compact bodies characteristically constructed of membranous tubules arranged as a cubic lattice and compact bundles of numerous 200 Å filaments. These structures have never been described in fungi before, and their possible relationships to each other, and to similar structures in plant cells are discussed.
Callus and cell suspension culture of bush bean (Phaseolus vulgaris)
Authors: Liau Deng-Fong , Boll W. G.
Published: September 2008

A solid medium was developed for callus cultures originating from explants of root, hypocotyl, and cotyledon of seedlings of bush bean, and a liquid medium was developed for the growth of cell suspension cultures derived from the callus cultures. Some unsatisfactory media are recorded. Concentrations of mineral salts for cell suspension cultures are lower than for callus cultures. Both coconut milk and other organic substances are required for maximum growth. With cell suspensions the effect of deproteinized coconut milk is the same as that of raw coconut milk but, with callus cultures, deproteinized coconut milk gives greater yield. There are no obvious differences in yield of callus derived from root, hypocotyl, or cotyledon. Few differences in yield were obtained between cell suspension cultures from root, hypocotyl, and cotyledon but those from root gave the highest yield in dry weight. However, in the same medium, cells from the three origins are very similar in form and appearance. Some effects of different media on cell form and clumping are described. The yield in suspension culture is very high. Increase in cell number, fresh weight, and dry weight is about 100-fold in 12 days involving about six to seven divisions per cell.
Separation of noncharged carbohydrates from plant material by gas–liquid chromatography of their trimethylsilyl derivatives
Authors: Hamlen R. A. , Lukezic F. L. , Bloom J. R.
Published: September 2008

A technique is described for the quantitative separation of very low concentrations of carbohydrates by gas–liquid chromatography using polar and nonpolar silicone liquid phases and TMS (trimethylsilyl) derivatives.
A simple mordant technique for plants with small chromosomes
Authors: Stringam G. R.
Published: September 2008

A new mordant technique using ferric acetate in Newcomer's fluid has given excellent results in species with small chromosomes. The method is simpler than others reported and has the added advantage of using a stable mordanted fixative.
A device for injecting solutions and suspensions into thin leaves of plants
Authors: Hagborg W. A. F.
Published: September 2008

An apparatus consisting of tongue-seizing forceps, soft rubber stoppers, and a hypodermic needle and syringe is described. It permits the flooding of areas in plant leaves by hydraulic pressure. The device has been used to permeate cereal leaves with bacterial suspensions, water, and chemical solutions.
Erratum: Histological studies of Melampsora lini resistance in flax
Authors: Littlefield Larry J. , Aronson Sandra J.
Published: September 2008

not available
Verticillium albo-atrum and V. dahliae as mycoparasites
Authors: Barron G. L. , Fletcher J. T.
Published: September 2008

Verticillium albo-atrum and V. dahliae, normally serious soil-borne pathogens of higher plants, can behave as destructive mycoparasites. Using Rhopalomyces elegans as the test host it was found that both species could readily penetrate the conidiophore walls and grow profusely in the conidiophores and vesicles. The hyphae of V. dahliae may penetrate from the vesicle through the spore connective and into the developing conidia preventing normal maturation in most cases. The significance of these findings in relation to the persistence of these fungi as soil-borne plant pathogens is discussed.
Some aspects of transmission and electron microscopy of necrotic leaf spot of aspen
Authors: Boyer M. G. , Navratil S.
Published: September 2008

Continued studies on the necrotic leaf spot disease of Populus tremuloides Michx. and related hybrids have verified transmission of the causal agent by grafting and demonstrated its passage through seed. Attempted transmissions by mechanical means to a wide variety of herbaceous hosts were negative except for extracts from two hybrids which induced necrotic spots on Vigna sinensis cv. Black Eye.Some aspects of disease development were revealed by electron microscopy. Attempts to visualize a causal agent were not successful but occasional virus-like aggregates were observed.
Composition de Chlorella pyrenoidosa, structure des cellules et de leurs lamelles chloroplastiques, en fonction de la carence en azote et de la levée de carence
Authors: Guérin-Dumartrait Eveline , Mihara Sayoko , Moyse Alexis
Published: September 2008

Autospores of Chlorella (produced in synchronized culture) become hypertrophied cells which have lost their capacity for cell division, when deprived of nitrogen during alternating light and dark periods.Biochemical analyses and electron microscopic studies (freeze-etching method) reveal an inhibition of protein and pigment syntheses and some chlorophyll degradation, while lipids and carbohydrates accumulate. The thylakoids appear to be somewhat degraded and their number per chloroplast is decreased.When nitrogen is supplied during the light period, a synthesis of proteins and pigments, and an increase in the thylakoids number are noted, while, simultaneously, the lipid and carbohydrate contents are diminished; this is followed by a re-establishment of cell division.Electron micrographs reveal a development of lamellar particles. According to their sizes and distributions, we can distinguish three kinds of superimposed or juxtaposed populations within the thylakoids lamella.The possible spatial arrangement of these particles is discussed.
Metabolism of proline in maize root tips
Authors: Barnard Ruth A. , Oaks Ann
Published: September 2008

During an initial 3-h incubation period, maize root tips loose 62% of their soluble proline. When intact roots are presented with proline-UL-14C for 30 min and subsequently excised, 80% of that proline is used in 3 h. Sixty-six percent of the convertible proline is oxidized to glutamic, malic, succinic, and citric acids, 34% is incorporated into protein as proline during the initial 30-min pulse.
Patterns of development of glycosidase activities in the pea epicotyl
Authors: Datko Anne Harmon , Maclachlan G. A.
Published: September 2008

Rates of hydrolysis of α- and β-linked glucosides and galactosides were compared in reaction mixtures containing nitrophenol derivatives, maltose, or cellobiose as substrates, plus enzyme derived from various parts of the third internode of the pea epicotyl. β-Glucosidase activity (EC. 3.2.1.21) per unit fresh weight, protein, or DNA was concentrated in meristematic tissues (plumule and hook) and nearly absent from adjacent growing and maturing regions in the internode. The other glycosidase activities showed no such specific localization. β-Glucosidase was also the only one of these enzymes that increased in specific activity in the decapitated epicotyl after treatment with indoleacetic acid. The increase (about twofold in 2 days) occurred if cell division was evoked at the same time. Treatment with gibberellic acid had little effect on any glycosidase activity. It is concluded that β-glucosidase activity may have been especially useful in cells during or shortly after cytokinesis, but none of the glycosidase activities were needed specifically for cell elongation or expansion.
Metabolism of acetate-2-14C, glycine-2-14C, leucine-U-14C, and effect of δ-aminolevulinic acid on chlorophyll synthesis in Gateway barley and its mutant
Authors: Sane P. V. , Zalik Saul
Published: September 2008

Studies with acetate-2-14C showed that leaves of light-grown seedlings of the mutant were less efficient in the synthesis of protein particularly at the 6-day stage. The synthesis of leucine from labeled acetate was also lower in the mutant at this stage. Metabolism of leucine-U-14C confirmed the lower rate of protein synthesis in light by the mutant at the 6-day stage whereas, in the dark, protein synthesis in the two lines was similar. There was essentially no difference in the use of labeled glycine by the two lines. Free and protein amino acids accounted for over 75% of the label. Glycine was rapidly converted to serine, which contained over 65% of the label in the free amino acid fraction but less than 50% of the label in the protein fraction. Evidence for the existence of two separate pools of serine was obtained. Only 3 to 5% of the label from glycine was detected in chlorophyll.Administration of δ-aminolevulinic acid increased chlorophyll synthesis in the mutant in the same proportion as it did in the normal. It was, therefore, concluded that inadequate production of δ-aminolevulinic acid or its precursors was not responsible for the virescent character of the mutant. Rather it seems that the mutation caused a partial inhibition of synthesis of chlorophyll holochrome protein which accounted for the slower accumulation of chlorophyll in the mutant.
Effect of nitrogen source on glutamate dehydrogenase and alanine dehydrogenase of Chlorella
Authors: Kretovich W. L. , Evstigneeva Z. G. , Tomova N. G.
Published: September 2008

During nitrogen assimilation by Chlorella a change in the source of this element produced a substantial effect on the activity of NADP-glutamate dehydrogenase and a smaller effect on the activity of alanine dehydrogenase. The activity of NAD-glutamate dehydrogenase was almost unaffected. NADP-glutamate dehydrogenase activity drastically increased upon cultivation on ammonium salts and decreased upon cultivation on nitrate. These changes resulted from an enhancement or reduction of the synthesis of enzymic protein. Glutamine, alanine, and α-ketoglutarate exerted no effect on the activity of the tested enzymes.
Use of labeled carbon dioxide for separation of CO2 evolution from true CO2 uptake by photosynthesizing Amaranthus and sunflower leaves
Authors: Fock H. , Becker J. D. , Egle K.
Published: September 2008

After 90 min of steady-state photosynthesis in a flow through gas circuit, illuminated Amaranthus and sunflower leaves were offered 14CO2 in a closed system and subsequently killed in liquid nitrogen. The lyophilized tissue was combusted by a modified in-vial microcombustion method. The radioactivity of the released carbon dioxide trapped in monoethanolamine was measured in a liquid scintillation spectrometer.CO2 evolution is not apparent in concentrations of low oxygen and the rates of 14CO2 uptake by photosynthesizing Amaranthus and sunflower leaves in 600 p.p.m. CO2 and 1% O2, which were constant during the short time 14C fixation, showed that the volume of the closed system was not rate limiting.In 600 p.p.m. CO2 and 50% O2Amaranthus leaves did not evolve carbon dioxide from recently fixed carbon-14. Under the same conditions the 14C content versus time relationship by sunflower leaves rapidly became curvilinear, indicating that increasing amounts of labeled carbon dioxide were being evolved from the tissue. Radioactive carbon was determined in the released carbon dioxide less than 1 min after the introduction of the 14CO2. The calculated minimum rate of CO2 evolution in the light was at least 5.5 mg CO2/h.dm2. The true values and kinetics can be approached if 14CO2 is fed for shorter periods of time.
Effects of preillumination with light of different wavelengths on subsequent dark CO2-fixation in Chlorella cells
Authors: Miyachi Shigetoh , Hogetsu Daisuke
Published: September 2008

The effects of preillumination with monochromatic red or blue light on the subsequent dark 14CO2-fixation in Chlorella cells were studied under aerobic as well as anaerobic conditions. When the cell suspension was made aerobic by bubbling air (CO2-free) throughout the periods of preillumination and the following dark 14CO2-fixation, the initial fixation product was mainly PGA. The radioactive carbon first incorporated in PGA was transferred mostly to aspartate during the later periods of dark 14CO2-fixation. The rate of 14C-incorporation into aspartate after preillumination with blue light was 2 to 3 times as high as that observed after red-light pretreatment. The observations support our previous inference that the activity of PEP carboxylase in Chlorella cells is stimulated by preillumination with blue light. When nitrogen gas was used during preillumination and the subsequent dark fixation, the radioactivity of 14C incorporated during the initial enhanced 14CO2-fixation was eventually transferred to alanine and lactate. The increase in radioactivity of alanine and lactate was more pronounced during dark fixation after preillumination with red light than after preillumination with blue light.
Some methods for studying the photosynthetic taxonomy of the angiosperms
Authors: Tregunna E. B. , Smith B. N. , Berry J. A. , Downton W. J. S.
Published: September 2008

Several methods are described for measuring some aspect of the photosynthetic apparatus. The results indicate the division of the members of several genera into two groups. Leaf anatomy, gas exchange, 14CO2 labeling, and carbon isotope ratio showed exact correlations in the species tested. The strengths and weaknesses of some of the techniques are indicated.
Enzymes of the glycolate pathway in plants without CO2-photorespiration
Authors: Rehfeld D. W. , Randall D. D. , Tolbert N. E.
Published: September 2008

Extracts, mainly from mesophyll cells, were obtained by grinding cells in a Waring Blendor; then extracts of parenchyma sheath cells were obtained by exhaustive grinding of the blender residue in a roller mill or mortar with sand. The specific activities of P-glycolate phosphatase, glycolate oxidase, catalase and reduced nicotinamide adenine dinucleotide- (NADH-) hydroxypyruvate reductase were fourfold higher in extracts of the parenchyma sheath cells than in the mesophyll cells from corn, sugarcane, and Atriplex rosea. P-Glycerate phosphatase was mainly located in the mesophyll cells. The total activity of glycolate oxidase in plants without CO2-photorespiration averaged about one-third that found in other plants on a wet-weight basis. Glycolate oxidase activity in Atriplex rosea, without CO2-photorespiration, was about the same as in Atriplex patula, with CO2-photorespiration. It is concluded that enzymes for glycolate metabolism are present in all leaves in substantial amounts and are located in both cell types, although a higher specific activity is in the parenchyma sheath cells. Thus it is proposed that photorespiration occurs in all plants, but that CO2 evolution from glycolate metabolism is not manifested in plants which have high levels of activity for the C4-dicarboxylic acid cycle of CO2 fixation.
Effet de l'ATP et de Mg2+ sur les activités ribulose-diphosphate carboxylase et ribose-5-phosphate isomérase et kinase d'une préparation enzymatique de chloroplastes
Authors: Champigny M. L. , Bismuth E.
Published: September 2008

CO2 fixation in the presence of Ru-DP or R-5-P, catalyzed by proteins precipitated from isolated chloroplasts, is affected by ATP. The enzymes of the chloroplastic preparation are mainly Ru-DP carboxylase, R-5-P isomerase and Ru-5-P kinase. ATP inhibits the activity of the Ru-DP carboxylase. This is true for the enzyme of the crude protein preparation as well as for the purified enzyme. The inhibition by ATP is overcome by Mg2+. This may be related to the formation of a chelate with ATP and Mg2+, which lowers the level of the Ru-DP carboxylase – Mg2+ – CO2 complex.However, R-5-P kinase activity is enhanced by ATP. As a result of the different responses of the two enzymes to ATP, CO2 fixation coupled to Ru-DP formation from R-5-P, is enhanced by low concentrations of ATP and inhibited by concentrations above 2 mM.
Role of protein synthesis in drought resistance
Authors: Henckel P. A.
Published: September 2008

One of the major protective adaptations of plants in response to drought is their ability to renew proteins during drought and to repair themselves rapidly after drought, i.e. after exposure to a combination of increased temperature plus dehydration. Corn plants subjected to presowing hardening were used as a model of plants with increased drought resistance. Such plants have a more drought resistant ultrastructure and form more high-energy substances, which promote synthetic processes in them. In hardened plants, 15N incorporation into proteins during and after drought proceeds at a faster rate than in control plants. Also, their ribonuclease is less active with respect to messenger RNA (ribonucleic acid), and polysome degradation into ribosomes and subunits occurs more slowly during drought. Polysomes revert to normal after drought faster in hardened than in non-hardened plants. All this explains the greater resistance of plants exposed to presowing hardening.
Light-induced O2 evolution, triphosphopyridine nucleotide reduction, and phosphorylation by chloroplasts of maize, sugarcane, and sorghum
Authors: Hew Choy-Sin , Gibbs Martin
Published: September 2008

The characteristics of the light-driven reactions triphosphopyridine nucleotide reduction, O2 evolution, and associated adenosine 5′-triphosphate formation in chloroplasts of maize, sorghum, and sugarcane were similar to those obtained in spinach chloroplasts.
Insensitivity of development of photosynthetic competence to doses of ultraviolet light which block green colony formation in Euglena
Authors: Diamond Jeffrey , Schiff Jerome A.
Published: September 2008

The Do for inactivation of chloroplast inheritance in Euglena gracilis var. bacillaris is 5.6 ergs/mm2. In contrast, the Do for the inactivation of light-induced chloroplast development from the proplastid in non-dividing cells as measured by chlorophyll formation and appearance of photosynthetic carbon dioxide fixation is 200–300 ergs/mm2. This strongly suggests that DNA replication in Euglena chloroplasts is far more sensitive to ultraviolet inactivation than is DNA transcription. Carrying this model further, a useful comparison can be made between Euglena chloroplasts and certain strains of Escherichia coli. Since the Do for inactivation of viability in two strains of E. coli lacking dark repair is about the same as the Do for inactivation of chloroplast inheritance, it is suggested that the chloroplast lacks a dark repair system. Furthermore, since the bacterial sensitivity has been ascribed to a few inactivations in the DNA which prevent successful replication, this has been adopted to explain the blockage of plastid replication. Inhibition of transcription of the DNA into RNA in these bacterial strains, however, requires much higher doses since many cistrons must be inactivated and the dose required compares favorably with that required for inactivation of chloroplast development in Euglena. From the data presented in this paper, previous data on the Euglena system, and the model derived from a comparison with E. coli, the chloroplast can be viewed as a triploid procaryote lacking dark repair and possessing exceptional ultraviolet sensitivity of chloroplast inheritance compared with development which can be ascribed to the amounts of damage in DNA required to affect DNA replication or transcription.
The effect of amitrole on duckweed
Authors: DeKock P. C. , Innes Alison M.
Published: September 2008

Aminotriazole applied to the surface of duckweed fronds as micro drops caused horizontal bands of chlorotic tissue to develop in the daughter fronds. Iron applied simultaneously was found to decrease the chlorotic response. Ultrastructure studies showed progressive disorganization in the affected cells.
A note on measurements of Onsager coefficients in maple petioles and maple woody xylem by electroosmotic techniques
Authors: Ursino D. J. , Fensom D. S.
Published: September 2008

Measurements on petioles and on 2- and 4-year old xylem of Acer saccharum have shown that the specific conductivity (LEE) measured after they were soaked in 10−4 N KCl was about 2 × 10−4 ohm−1 cm−1 and did not change significantly through the growing season in these plant tissues. On the other hand the electrokinetic coefficient (LPE) varied seasonally in the petioles with a value of about 3 × 10−6 in spring and 3 × 10−5 cm2 s−1 volt−1 in summer. The electrokinetic coefficient in the woody xylem measured about 6 × 10−5 cm2 s−1 volt−1. From the values of these Onsager coefficients the contribution of electroosmosis to phloem transport would seem to be negligible in these cut sections.
Inoculation of western white pine tissue cultures with basidiospores of Cronartium ribicola
Authors: Harvey A. E. , Grasham J. L.
Published: September 2008

Rust infections were established in healthy, undifferentiated tissue cultures of Pinus monticola Dougl. by direct inoculation with germinating basidiospores of Cronartium ribicola J. C. Fisch. ex Rabenh. Infections were verified by confirming the presence of typical rust haustoria and extensive intracellular ramification by the mononucleate rust mycelium.
Studies of western tree rusts. VII. Inoculation experiments with pine stem rusts (Cronartium and Endocronartium)
Authors: Ziller Wolf G.
Published: September 2008

Results from 35 cross-inoculation experiments provide confirmatory and new information on the life histories and taxonomy of Cronartium coleosporioides Arth., C. coleosporioides f. album f. nov., C. comptoniae Arth., Endocronartium harknessii (J. P. Moore) Y. Hirats., and the Peridermium filamentosum complex. Stalactiform rust (Peridermium stalactiforme Arth. & Kern) is accepted to be the aecial state of Cronartium coleosporioides; there is no evidence of its direct spread from pine to pine. A white-spored form of C. coleosporioides is named and described from specimens obtained by inoculation. Gall rust of western Canada appears to belong to the autoecious Endocronartium harknessii; there is no evidence that heteroecious forms of it occur in western Canada. The existence of heteroecious and autoecious forms of limb rust (Peridermium filamentosum complex) is confirmed by inoculation results and germ-tube morphology. No morphological difference in the uredinial or telial states could be found between heteroecious limb rust and Cronartium coleosporioides.
Some Asterinaceae and Meliolaceae on conifers in Canada
Authors: Pirozynski K. A. , Shoemaker R. A.
Published: September 2008

Three ascomycetes occurring on conifer needles in Canada are described: Appendiculella pinicola (Dearn.) comb. nov. (basionym: Meliola pinicola Dearn.), Asteridiella pitya (Sacc.) Hansf., and Maurodothina gen. nov. (type species: M. dothideoides (Ell. & Ev.) comb. nov.) with M. farrae sp. nov.
Epidemiological and ecological relations of Xanthomonas phaseoli and X. phaseoli var. fuscans on beans in southwestern Ontario, 1961–1968
Authors: Sutton M. D. , Wallen V. R.
Published: September 2008

The effects of introducing new varieties and bacterial strains upon the epidemiology, ecology, and control of Xanthomonas phaseoli and X. phaseoli var. fuscans in registered bean seed crops in southwestern Ontario between 1961 and 1968 are described. A new phage type of X. phaseoli, Ib, is reported. Problems related to plant introductions and the detection of seed-borne pathogens are discussed.
Sporulation of Gibberella zeae. III. Carbon and nitrogen nutrition on growth and macroconidium production
Authors: Bonn W. G. , Cappellini R. A.
Published: September 2008

Differences in growth rates and macroconidium production occurred between shake and standing cultures of a non-sporulating strain of Gibberella zeae (Schw.) Petch. Good growth occurred on all carbon sources except lactose, acetate, citrate, and α-ketoglutarate, and on all nitrogen sources except NaNO2. The pH of the media changed during growth, dropping to about 3 with the sugar and rising to about 9 with the organic acid and nitrogen sources. Little or no sporulation was observed in standing cultures. Sugars appeared to inhibit, and tricarboxylic cycle acids, aspartic acid, and phenylalanine stimulated sporulation.
A change in color of aging mycorrhizal roots of Tilia americana formed by Cenococcum graniforme
Authors: Park Jai Y.
Published: September 2008

It is accepted that mycorrhizae formed by Cenococcum graniforme (Sow) Ferd. & Winge are characteristically black. From the data reported here it is apparent that, contrary to this view, mycorrhizal roots formed by this symbiotic fungus may also be brown as well as white. Anatomical studies have led to the conclusion that the differences in color of mycorrhizal roots formed by C. graniforme are related to the physiological state of the symbiotic relationship. Apparently, the white mycorrhizae reflect the early period of the symbiosis and the black mycorrhizae indicate the period at which the symbiotic association begins to deteriorate. Experimental evidence indicates that mycelium of C. graniforme in pure culture changes color through aging and also through certain changes in nutritional conditions.
The phytochrome system, phenolic compounds, and aplanospore formation in a lichenized strain of Trebouxia
Authors: Giles K. L.
Published: September 2008

Aplanospore formation in a strain of Trebouxia isolated from the lichen Cladonia cristatella was found to be influenced by the phytochrome system. The effect of several concentrations of indoleacetic acid (IAA) and various phenolic compounds was tested, and their interaction noted. Coumarate was found to act non-competitively in inhibiting the effect of both chlorogenate and ferulate.
Assimilation and release of internal carbon dioxide by woody plant shoots
Authors: żelawski W. , Riech F. P. , Stanley R. G.
Published: September 2008

This study was undertaken to determine whether tree stems can reassimilate internal CO2 produced by respiration or whether this CO2 is evolved and could possibly interfere with measurements of leaf gas exchange. Radioactive CO2 was added to the stem transpiration stream of slash pine seedlings (Pinus elliottii Engelm.) and the distribution of 14C studied in shoots and needles exposed to dark and light conditions.Photosynthesis decreases the amount of internal CO2 evolved. Large amounts of 14CO2 from the transpiration stream are incorporated into organic compounds of needles and stems, primarily into ethanol-soluble sugars and organic acids, and in time, small amounts of 14C occur in the ethanol-insoluble materials.These results indicate that respiratory CO2 transported in the transpiration stream of woody plants can be reused in photosynthesis or possibly other metabolic processes. Internal CO2 is also evolved to the atmosphere in large amounts, but related research indicates it diffuses primarily out of the stem tissue not the needles. The evolved CO2 supplied from stems does not significantly affect short term measurements of needle gas exchange in pine seedlings.
In vitro studies of floral shoot apices of Pharbitis nil
Authors: Bhar D. S.
Published: September 2008

Shoot apices of Pharbitis nil were excised and cultured in vitro at different intervals after the intact plants were photoperiodically induced. The induced apices excised immediately after and up to 24 h after an inductive dark period, grew vegetatively for at least 4 weeks in culture. The apices excised and cultured from intact plants at 36 and 48 h after induction initiated a full complement of floral-organ primordia when observed after 4 weeks of growth.
Light and temperature effects on the growth, morphology, and reproduction of Petalonia fascia
Authors: Hsiao Stephen I. C.
Published: September 2008

Responses of the four morphological types of Petalonia fascia to light intensity and photoperiod, and to temperature variations, were determined in a defined medium. Protonemata and plethysmothalli grew in even the most extreme experimental culture conditions. Ralfsia-like thalli and blades developed under all light intensities tested at 16 C. Best thallus growth and earliest zoospore production from the blades were found in continuous light.The combined effects of light and temperature on the development of P. fascia are discussed. These two parameters may determine its morphological life history.
Variations in cell length and frequency of anticlinal division in the vascular cambium throughout a white spruce tree
Authors: Bannan M. W. , Bindra M.
Published: September 2008

In the early growth of the stem, branches, and roots, the vascular elements are relatively short and the frequency of anticlinal division involved in cambial cell multiplication is high. As growth sheaths are added in the stem, length of cell increases and rate of multiplicative division declines. A similar trend occurs upward through the lower quarter to half the height of the stem. In the root system, the later growth of vertical roots is characterized by shortness of cell and high frequency of anticlinal division, and conversely, that of horizontal roots by great length of cell and low rate of anticlinal division. Although a general negative relationship exists between rate of anticlinal division and cell length throughout much of the tree, these features sometimes vary independently, and length of cell seems to be more closely related to amount of yearly radial accretion. Through the middle to late growth of the stem a negative relationship obtains between length of cell and width of annual ring, cell length maximating at a ring width of 1–2 mm. At this stage, frequency of division may fluctuate only narrowly over a considerable range of ring width. A continued decline in ring width to less than 0.5 mm, such as may occur on senescence, is accompanied by decreased cell length and accelerated anticlinal division. Length of the cell plate in anticlinal division, relative to that of the dividing cell, is greater in the early growth of the stem and branches and throughout horizontal roots than elsewhere in the tree. Most of the anticlinal divisions are pseudotransverse. The proportion of lateral divisions ranges from about 1% in the late growth of stems to 11% in horizontal roots.
The problem of classifying cultivars with special emphasis on oat (Avena) cultivars
Authors: Baum Bernard R.
Published: September 2008

Oat cultivars, although superficially homogeneous, contain much variability and intergrade with one another. The same cultivar may vary from year to year, and from one locality to another in the same year. Existing methods of classification, which are mostly regional, are inadequate for worldwide application. It is stipulated that worldwide classification of oat cultivars in particular, and cultivars in general, be based on as many attributes as possible requiring the use of the techniques of numerical taxonomy.This paper demonstrates that there is no correlation and no conformity between existing systems of classification of oats and the phylogenies of the oat cultivars. Moreover the various specific and infra-specific taxa according to the different systems are recurrent in many pedigrees and clearly manifest the polyphyletic origin of the key characters of these taxa.Because of the lack of conformity between the genealogic relationships of the cultivars with any of the existing classifications, it is concluded that two independent goals in taxonomy of cultivated oats particularly, and taxonomy of cultivars in general, should be undertaken separately: (1) construction of genealogies, (2) classification and identification.
The viable seed content of some forest soil in coastal British Columbia
Authors: Kellman M. C.
Published: September 2008

The upper 10 cm of surface soil and litter beneath a coniferous forest in coastal British Columbia was found to contain over 1000 viable seeds per square meter. Alnus rubra Bong. made up 68.9% of all viable seed, although 18 other species, mainly weedy and secondary types, were recorded.
Description de la tourbière à sphaignes Mer Bleue près d'Ottawa. I. Végétation
Authors: Joyal Robert
Published: September 2008

The "Mer Bleue" is an important 5000-ac peat bog situated 10 mi east of Ottawa. Phytosociological and ecological studies proved that the Mer Bleue is a Sphagnum ombrotrophic raised bog. A total of 10 associations and 3 subassociations are recognized and described, including 2 new associations (Sphagno–Calamagrostetum and Polytricho–Populetum). The most important communities are heath associations (Chamaedaphne and Ledum) and black spruce stands.Occasional fires retard normal succession here and there and a ditch dug in 1938 is changing irrevocably the physiognomy of the east section where drainage permits the invasion of Vaccinium myrtilloides, Populus tremuloides, Betula populifolia, and many herbs usually excluded from an ombrotrophic bog. Sphagnum magellanicum is the most widespread of the 54 bryophytes encountered. Chamaeophytes are dominant in ombrotrophic sites, being somewhat replaced by hemicryptophytes where minerotrophic conditions prevail.
Studies in the Arundinelleae (Gramineae). IX. Chromosome numbers of 21 species
Authors: Phipps J. B. , Mahon J. B.
Published: September 2008

The chromosome numbers of 22 specimens of Arundinelleae are given, of which 19 counts are the first published for their species. Together with previously recorded counts of 23 other species, it is now possible to see that x = 10 is commonest for major groups B and C and x = 12 for major group D. The further counts for major group A still do not enable one to select a single characteristic base number for that group.
Activity of gibberellin A17 in 13 bioassay systems
Authors: Hoad G. V. , Kuo C. C.
Published: September 2008

The activity of gibberellin A17 (GA17) was relatively low in the bioassay systems in which it was tested. The dock leaf senescence assay was the most sensitive of those used, followed by the oat mesocotyl, dwarf rice, and barley half-seed assays. In the cucumber hypocotyl, lettuce hypocotyl, excised pea epicotyl, oat leaf, and d-1 maize mutants, the activity of GA17 was only marginal. In the intact dwarf pea, d-2, d-3, and d-5 maize mutant assays no activity was recorded.
Cytotaxonomic studies of Draba glabella and its close allies in Canada and Alaska
Authors: Mulligan Gerald A.
Published: September 2008

The cytotaxonomy of the following group of leafy-stemmed, white-flowered species of Draba is discussed and a key is presented: D. glabella Pursh (2n = 64 and 80), D. arabisans Michx. (2n = 96), D. borealis DC. (2n = 80), D. longipes Raup (2n = 64), D. incana L. (2n = 32), and D. norvegica Gunn. (2n = 48). Scanning electron microscopic examinations were made on the morphology of pollen grains and basal leaf hairs.
Reactions to stem rust and genetics of stem rust resistance in European wheat varieties
Authors: Bartoš P. , Green G. J. , Dyck P. L.
Published: September 2008

Thirty-four European wheat cultivars were classified into eight groups according to their reactions to seven North American races of Puccinia graminis f. sp. tritici. Cultivars of seven groups were crossed with a variety or single gene line having similar rust reactions. These crosses indicated that the resistance of Hybrid 80-3, Stabil, and Vrakuňská (group 1) was conferred by stem rust resistance gene Sr5; Admonter Früh (group 2) carries Sr5 and an unidentified gene; Flevina (group 4) carries Sr11; Erythrospermum 974 (group 5) carries Sr5 and Sr8; Étoile de Choisy (group 6) carries an unidentified gene for moderate resistance to all the races used; and Mironovskaja 808 (group 7) and Belocerkovskaja 198 (group 8) each carry an unidentified gene. The five cultivars in group 3 were not studied genetically but they react like Marquis and may carry Sr7b.
Fungal symbionts of the ambrosia beetle Gnathotrichus sulcatus
Authors: Funk A.
Published: September 2008

Three species of Fungi Imperfecti associated with the ambrosia beetle Gnathotrichus sulcatus Lec. are described in culture, viz. Ambrosiella sulcati Funk sp. nov., Raffaelea sulcati Funk sp. nov., and Graphium sp. All are found in beetle mycangia and in tunnels of specimens from British Columbia, Canada.
Fine structure of sunflower crown gall tissue
Authors: Manocha M. S.
Published: September 2008

Electron microscopic examination of thin sections from sunflower crown gall tissue, induced by Agrobacterium tumefaciens, revealed certain details about its intracellular organization not previously reported. Tumor tissue showed a marked increase in the number of ribosomes, endoplasmic reticulum, and Golgi dictyosomes, over that of normal mesophyll cells. Mitochondria and chloroplasts did not show any detectable change. Crystalline bodies, consisting of a lattice surrounded by a unit membrane, were frequently observed in tumorous cells. The nucleoli of tumor cells contained vacuoles and were clearly differentiated into two zones, pars amorpha and nucleolonema. The possible significance of these ultrastructural changes has been discussed. Small vesicle-like bodies were observed in the nuclei of mesophyll cells 4 days after bacterial inoculation. Whether or not these vesicle-like bodies are responsible for the transformation of a normal mesophyll cell to a fully autonomous tumor cell is not known, but the possibility is an intriguing one.
Aboveground standing crop, leaf area, and caloric value in an aspen clone near Calgary, Alberta
Authors: Peterson E. B. , Chan Y. H. , Cragg J. B.
Published: September 2008

A 1967 aboveground harvest of 49 ramets of aspen (Populus tremuloides Michx.), aged from 66 to 89 years, at an altitude of 1430 m in Alberta revealed a leaf area index of 1.8 (one side of foliage) and a clone standing crop of 77.11 metric tons/hectare (oven-dry weight) with an energy equivalent of 3630 × 108 gram calories/hectare. This standing crop estimate fell within the range of 58 to 290 metric tons/hectare reported elsewhere for aspen. The amount of aspen foliage and branch wood, as a percentage of total aboveground standing crop, increased from the bottom to the top of a slope gradient within the 0.02-hectare sample plot, indicating that topographic position exerted a phenotypic expression on production structure within the clone. Topographic position did not have a significant influence on the applicability of the two most reliable independent variables ((i) diameter at breast height squared × tree height, (ii) diameter of trunk at crown base) for prediction of the total aboveground weight and component weights of aspen ramets. The allometric relations reported here are not necessarily applicable to other clones of the species but the allometric methods have potential application to other studies of the International Biological Programme.
Studies of western tree rusts. VIII. Inoculation experiments with conifer needle rusts (Melampsoraceae)
Authors: Ziller Wolf G.
Published: September 2008

Results from 22 cross-inoculation experiments provide confirmatory and new information on broom rusts of spruce and fir (Chrysomyxa arctostaphyli Diet. and Melampsorella caryophyllacearum Schroet.) and needle rusts of pine, larch, and fir (Coleosporium asterum (Diet.) Syd., Melampsora paradoxa Diet. & Holw., Pucciniastrum epilobii Otth, Uredinopsis longimucronata Faull, U. phegopteridis Arth., and U. struthiopteridis Stoerm. ex Diet.). New host and distribution records are confirmed by inoculation. Cone rust of alpine fir is shown to be caused by Pucciniastrum epilobii. The need for further study of needle rust of pine (Coleosporium) and a monographic treatment of the willow rusts (Melampsora epitea complex) is suggested.
On the variability of spherosome-like bodies in Phaseolus vulgaris
Authors: Mishra A. K. , Colvin J. Ross
Published: September 2008

Root and shoot apices and primary leaves of 3- to 4-day-old seedlings of Phaseolus vulgaris L. were examined in the electron microscope after fixation with (a) glutaraldehyde followed by osmium tetroxide, (b) glutaraldehyde followed by potassium permanganate, (c) osmium tetroxide alone, and (d) potassium permanganate alone. The distribution, shape, and substructure of the spherosome-like bodies in the cytoplasm varied markedly depending upon the tissue, its age, and the fixation used. Shapes varied from stellate through polygonal to spherical. The electron density of the interior of the organelles varied from uniformly dark after osmium tetroxide fixation to almost none after permanganate fixation. In addition to differences caused by fixatives, marked variation of the electron density of the same organelles with identical fixation was observed. Structural, and possibly physiological, heterogeneity seems to be characteristic of spherosomes but in spite of their variability, they may be recognized in the electron microscope as a group of similar structures distinct from other organelles.
Dermea rhytidiformans n. sp., the fungus associated with cork-bark of alpine fir
Authors: Funk A. , Kuijt Job
Published: September 2008

Dermea rhytidiformans Funk & Kuijt n. sp. is described from cork-bark disease of alpine fir (Abies lasiocarpa (Hook.) Nutt.) in British Columbia, Canada; the conidial state is Micropera sp. Cultural characteristics and life history observations of the fungus are presented with evidence of its causal role in the disease.
Relation between industrialization and the distribution and growth of epiphytic lichens and mosses in Montreal
Authors: LeBlanc S. C. Fabius , Sloover Jacques De
Published: September 2008

Epiphytic mosses and lichens are very sensitive to air pollution. Their gradual disappearance from large cities and from the vicinity of industrialized complexes is due, mostly, to phytotoxicants. A simple method to map the long-range effect of air pollution on corticolous epiphytes is described. An I.A.P. or "index of atmospheric pollution" based on the number of species present, their coverage and frequency, and their specific tolerance to pollutants can be expressed quantitatively.
Evidence for injury as a cause of tree root branching
Authors: Wilson Brayton F.
Published: September 2008

Abnormalities in the primary xylem are characteristic of the lateral and terminal branching induced by root tip decapitation. Similar abnormalities in old, excavated root branches are evidence that previous injury caused the branching.
Properties and formation of the squash high-affinity glucose transport system
Authors: Hancock Joseph G.
Published: September 2008

Uptake of 3-o-methylglucose (MeG) by excised squash (Cucurbita maxima Dcne) hypocotyl sections and other plants increased greatly with age. A high-affinity (HA) transport system, with an apparent Michaelis constant (Km) of 0.6–0.8 mM, was formed during ageing in squash sections and was probably responsible for the enhanced MeG uptake. Net transport occurred against a concentration gradient in aged tissues. Accumulation of MeG by freshly excised sections, which possessed a low-affinity (LA) transport system (Km, 25–45 mM), was negligible. Glucose competitively inhibited MeG uptake by both the LA and HA systems and appeared to be the preferred substrate in vivo. When sections were bathed in glucose or galactose, an efflux of preabsorbed MeG occurred. Though inhibited by UO22+, uptake of MeG by the HA system was not affected by Ca2+, Mg2+, or K+.Glucose (10 mM) and indoleacetic acid (> 0.1 mM) repressed the formation of the HA system, while kinetin, gibberellin, and indoleacetic acid at lower concentrations (< 0.01 mM) had no effect.
Ultrastructure of lichen haustoria: symbiosis in Parmelia sulcata
Authors: Webber Mukta M. , Webber P. J.
Published: September 2008

Fine structure of haustoria in Parmelia sulcata Tayl. has been investigated. Electron micrographs show that haustoria of this lichen probably penetrate the algal cells by mechanical as well as biochemical means. Presence of mesosomes and "lysosome-like organelles" in the haustoria suggests that the penetration may be brought about by enzymatic digestion of the algal cell wall and that the fungal cell may further produce enzymes to digest the algal cell contents. Abundance of mitochondria near the haustorial origin indicates a site of increased metabolic activity. If further investigations produce evidence that the "lysosome-like organelles" are true lysosomes, then these findings are of phylogenetic significance with regard to the evolution of cell organelles. Symbiosis (obligate mutualism) in this lichen is characterized by the harvesting of algal cells by the fungus.