bluuebunny/crossref_metadata_2025 huggingface dataset:
Amino acids, soluble proteins, and isoenzyme patterns of peroxidase during the germination of jack pine
Authors: Ramaiah P. K. , Durzan D. J. , Mia A. J.
Published: September 2008

In germinating jack pine, changes in nitrogenous compounds were separated into two phases, the first, where through imbibition, seeds expanded but the prospective seedling remained enclosed by the haploid and nutritive female gametophyte (0 to 3 days), and second, when radicles emerged and only cotyledons remained in contact with the gametophyte (4 to 11 days).During imbibition, total soluble N in seeds dropped and the amino acid pool was dominated by high levels of free arginine. As levels of arginine N declined the greatest changes in percentage composition involved glutamic acid (gametophyte) and glutamine (embryo). Thereafter, arginine N accumulated. By 7 days, arginine N was recovered in seedlings primarily from cotyledons. High asparagine levels were observed in stems and roots as glutamine N in the emerging seedling declined.Protein reserves in the seedling were nearly depleted by 4 days. Total protein and, at later stages, the ratio of hexone bases to dicarboxylic acids was generally higher in the gametophyte than in the seedling. Soluble proteins of the embryo were separated into at least 18 bands by disc electrophoresis and contained peroxidase activity which increased strongly after the first week of germination. The increase of nine isoenzymes of peroxidase with mobilities towards the anode correlated with the histochemical localization of peroxidase at the emerging shoot and root tips and throughout the vascular tissues.
Influence of some nitrogen and vitamin sources on growth, sporulation, and pathogenicity of Cochliobolus sativus
Authors: Clark R. V.
Published: September 2008

Four isolates of C. sativus that had shown tendencies to give a differential pathogenic response when used to inoculate the foliage of several cereals grew well on a number of inorganic and organic nitrogen sources but showed no benefit from the addition of several vitamins. In general, the four isolates were consistent in their relative growth pattern although on occasion the order was changed slightly and when compared every 2 days a number of variations were noted. In some cases the amount of sporulation by the isolates was changed by certain chemicals. There was little evidence of a differential pathogenicity with inoculum grown on media containing different amino acids. However, inoculum grown on media containing methionine and isoleucine produced strikingly atypical leaf lesions on barley and wheat.All nitrogen sources tested supported some growth with the possible exception of cysteine. Comparing amino acids, maximum growth occurred on histidine, threonine, and hydroxyproline when equal amounts of sodium nitrate and amino acid were added to the basal medium, and on histidine, valine, and serine when only amino acid was used as the nitrogen source. With most acids growth was rapid for the first few days after inoculation and considerably slower later. In two cases practically no growth occurred during the second week of incubation. A chromatographic study of the culture filtrates showed that there was a variation in the speed at which the amino acids were taken up by the isolates. Several acids that supported rather poor growth were used up very quickly.
Benzyladenine as a regulator of chlorophyll synthesis in cucumber cotyledons
Authors: Fletcher R. A. , McCullagh Dianne
Published: September 2008

Pretreatment of etiolated cucumber cotyledons (4–10 days old) with benzyladenine (BA) increased the amount of chlorophyll produced in light. BA also eliminated the lag phase in chlorophyll formation, which in the water controls lasted for [Formula: see text]. Addition of δ-aminolevulinic acid (ALA) to the etiolated cotyledons resulted in the production of protochlorophyllide (PCHLD) in the dark. The BA-pretreated cotyledons did not make any PCHLD in the dark. The inhibitors of RNA and protein synthesis, actinomycin D, chloramphenicol, and cycloheximide (CH), inhibited BA's effect on chlorophyll production, with CH being the most effective. We propose that BA's effect on increased chlorophyll formation is mediated by inducing production of proteins including ALA synthetase, the rate-limiting enzyme in chlorophyll biosynthesis.
On Papulaspora and bulbilliferous basidiomycetes Burgoa and Minimedusa
Authors: Weresub Luella K. , LeClair Patricia M.
Published: September 2008

It is proposed that Papulaspora Preuss be restricted to fungi producing papulaspores, which are defined as thallodic propagules differentiated almost from inception into central and sheathing cells. Exclusion from Papulaspora is recommended for species such as P. acinosa (Berk. & Curt.) Hughes, P. Candida Sacc., and others whose propagules differ from papulaspores in development and final structure. Bulbils are distinguished as homogeneous throughout development and pseudoparenchymatous at least at maturity. These are the vegetative propagules of basidiomycetous fungi segregated from Papulaspora into Burgoa Goidànich (lectotype species B. verzuoliana Goid.), several species of which are known to produce perfect states determinable as Sistotrema brinkmannii aggr., and Minimedusa Weres. & LeClair gen. nov. (type species P. polyspora Hots.), for which no perfect state is known.
Inhibition of flower development in Chenopodium rubrum by a photosynthetic inhibitor
Authors: Sawhney Ramma , Cumming Bruce G.
Published: September 2008

Cumming 1969 has demonstrated that the short-day plant Chenopodium rubrum (60°47′ N) is induced to flower if inductive darkness is substituted by a relatively long exposure to a low intensity light of a low red/far-red ratio (light emitted by BCJ lamps). DCMU (3(3,4-dichlorophenyl)-1,1-dimethyl urea), a photosynthetic inhibitor, inhibited flowering if applied during this inductive BCJ light period.Our experiments show that ascorbic acid and dichlorophenol-indophenol (which have been used as reducing agents in photosynthesis by various workers) overcome the effect of DCMU on flowering. Sugars are also effective in overcoming the DCMU effect. This indicates that DCMU acts specifically on photosynthesis and that there are no side effects.In Cumming's experiments DCMU was supplied at the start of a BCJ inductive period and then washed off at the end of the BCJ period. However, there are indications that DCMU may persist in the plant for several days after the medium on which plants are growing has been thoroughly washed off. This raises the question whether the action of DCMU is on induction in BCJ light or on subsequent development in white light. By applying DCMU during the BCJ period and terminating its effect by ascorbic acid + dichlorophenol-indophenol or sugars at the time of transferring to white light, no inhibition of flowering was found. This suggests that inhibition of photosynthesis during the inductive BCJ light had no detrimental effect on flowering. The inhibition of flowering by DCMU might be a result of inadequate photosynthesis in white light for development of floral primordia.
Coniochaeta malacotricha: anomalous asci and the conidial state
Authors: Rogers Jack D. , Grand L. F.
Published: September 2008

Aberrant aspects of ascospore production in a North Carolina collection of Coniochaeta malacotricha are discussed. The conidial state of C. malacotricha is described.
Preserving barley stripe mosaic virus in leaves by drying with anhydrous magnesium perchlorate
Authors: Hagborg W. A. F.
Published: September 2008

Anhydrous magnesium perchlorate was used to dry barley leaves infected with barley stripe mosaic virus (BSMV). Infectivity and virulence were preserved at least 10 years in leaf samples sealed in vacuo or in nitrogen gas and stored at 2–12 °C.
Surface structure of germinating Uromyces dianthi urediospores as observed by scanning electron microscope
Authors: Jones D. R.
Published: September 2008

Germ pore regions could not be located on the surface of Uromyces dianthi urediospores before germination. Germ tube emergence did not split the spore wall. Double spine features were observed on the spore surface.
Low temperature effects on growth and physiology specific to a "grass-clump" dwarf wheat hybrid
Authors: Mahon J. D. , Canvin D. T.
Published: September 2008

The growth habit of "grass-clump" dwarf wheat plants can be affected by extremely short 16° treatments if given repeatedly. To localize the earliest growth responses in plants of one such hybrid (Mql × KF 1), the temperature sensitivity of plants of different ages, and the earliest temperature-induced changes in growth, development, and shoot physiology were investigated and compared with the responses of normal wheat plants.Mql × KF 1 plants growing at 26° responded to progressively shorter 16° treatments as they aged and plants exposed to 16° after 10 days growth at 26° were unable to recover from low temperature treatments of 3–5 days duration. Although shoot growth (as dry weight) of Mql × KF 1 stopped abruptly after 7 days at 16°, root growth (as dry weight) continued for at least 15 days. The rates of CO2 and water vapor exchange in individual leaves responded to low temperature similarly in both the dwarf and normal plants and did not markedly decrease until after 4 days at 16°. The most rapid low temperature response specific to Mql × KF 1 plants was cessation in primary tiller development immediately after the beginning of 16° exposure. It is proposed that the primary 16° effect is on the shoot meristematic region and that other changes in growth and physiology result from the lack of meristematic activity in the young growing region.
Comparisons of poa semilatent and barley stripe mosaic viruses
Authors: Polák Z. , Slykhuis J. T.
Published: September 2008

Poa semilatent virus (PSLV), which caused chlorosis and rapid death of inoculated wheat, infected a number of grasses susceptible to barley stripe mosaic virus (BSMV); but it also infected Agropyron trachycaulum and Poa palustris which were not susceptible to a barley strain or two oat-infecting strains of BSMV. Conversely BSMV caused local lesions on several species of Chenopodium that did not become infected with PSLV. BSMV protected wheat from infection by PSLV, but PSLV caused only partial protection from BSMV.The normal length and thickness of particles in leaf-dip preparations was 161 × 26 mμ for PSLV and 133 × 25 mμ for BSMV.Serological relationship was not indicated by the Ouchterlony agar double-diffusion test or leaf-dip serology. A distant relationship was shown with the microprecipitin test and the ring interface precipitin test. In cross absorption tests the titers of the antisera to the homologous viruses were not reduced by absorption with the heterologous viruses.PSLV and BSMV appear to be distantly related serotypes.
Low temperature induced metabolic changes in the shoot meristematic region of Marquillo × Kenya Farmer wheat dwarf 1 plants
Authors: Mahon J. D. , Canvin D. T.
Published: September 2008

Marquillo × Kenya Farmer 1 (Mql × KF 1) wheat plants respond to very short 16° treatment by decreased meristematic activity of the apical meristem and extensive cellular destruction in young leaf and stem tissues. By radiotracer techniques the metabolism of 3H-thymidine, 32P, and 14C-leucine fed to intact shoot tissues of Mql × KF 1 and normal Marquillo (Mql) plants were studied.Immediately after the onset of 16° treatment, the incorporation of both 3H-thymidine and 32P into the DNA of Mql × KF 1 meristematic regions began to decline rapidly although the total uptake of label into the meristematic tissue remained constant. The incorporation of 32P into the RNA, the acid-soluble organic phosphate compounds, and phospholipids of the Mql × KF 1 meristems also declined during the first 24 h and the inorganic phosphate radioactivity increased. After the initial decrease, the proportion of radioactivity in the RNA and acid-soluble organic compounds increased to near control levels. The distribution patterns of both 3H-thymidine and 32P were unchanged in the meristematic region of Mql × KF 1 plants at 26° or Mql plants at 16° or 26°. Protein synthesis in meristematic regions, measured by the incorporation of 14C-leucine, responds to temperature similarly in Mql × KF 1 and Mql plants.The inhibitions of mitosis, phospholipid synthesis, and DNA synthesis were extremely rapid and reversible after short 16° exposures, and are thought to be close to the primary process of temperature lethality of Mql × KF 1 plants. Although it is not known if any of these processes are responsible for the others, it is proposed that the cellular destruction is caused by the inability of cells in the elongating regions to synthesize the phospholipid components of membranes.
The behavior of ATPase in cotyledon tissue during germination
Authors: Lai Y. F. , Thompson J. E.
Published: September 2008

The behavior of ATPase in cotyledon tissue of Phaseolus vulgaris during germination has been examined with a view to assessing the feasibility of its involvement in transport processes. Both basal ATPase activity (no cations added to the assay mixture) and Na+–K+ stimulated activity were routinely present in homogenates of the tissue but decreased during germination in a manner that corresponded very closely with the pattern of protein attenuation for the same period. Since the decreased levels of protein primarily reflect protein body digestion, this parallel behavior suggests that as the need for transport of metabolites out of the storage cells becomes less, there is a corresponding decrease in the levels of basal and cation-stimulated ATPases.Fractionation of the tissue revealed that ATPase activity is present in isolated soluble fractions, but throughout the germination period the major proportions of both basal and Na+–K+ stimulated activities proved to be particulate and were distributed among nuclear, mitochondrial, and microsomal fractions. Since both types of ATPase are present in purified cell wall and plasma membrane from this tissue, this distribution is thought to reflect in large part fragmentation of cell wall and plasma membrane incurred during homogenization. Thus the subcellular distributions of the enzymes as well as their patterns of change during germination are consistent with the involvement of a major part of the cotyledon ATPase activity in transport phenomena.
Three new species of Arnium
Authors: Cain R. F. , Mirza J. H.
Published: September 2008

Three new species of Arnium Nits. in Fuckel are described and illustrated. These are A. ovale on dung of deer, goat, and horse from British Columbia and Saskatchewan, Canada, and San Luis Potosi, Mexico; A. subtile on cow dung from Ontario, Canada, and Oklahoma, United States; and A. villosum on dung of burro and goat from Durango, Jalisco, and San Luis Potosi, Mexico.
A comparative study of growth in Bumilleriopsis filiformis, B. peterseniana, and Pseudobumilleriopsis pyrenoidosa (Xanthophyceae)
Authors: Pecora Richard A. , Rhodes Russell G.
Published: September 2008

Growth of Bumilleriopsis filiformis Vischer, B. peterseniana Vischer, and Pseudobumilleriopsis pyrenoidosa Deason was compared in axenic culture. B. filiformis and B. peterseniana grew optimally at 20C and P. pyrenoidosa grew optimally at 16C in Bold's basal medium (BBM). No strain grew at 28C; B. peterseniana did not grow at 24C. Increased initial pH levels had minimal effect on the growth rates of B. peterseniana and P. pyrenoidosa but reduced the growth rate of B. filiformis. Experiments with B. filiformis and P. pyrenoidosa indicated an absence of heterotrophic growth; however, growth differences were apparent in BBM variously modified with organic compounds. B. peterseniana did not use any organic nitrogen source. B. filiformis and P. pyrenoidosa grew in media with ammonium acetate or ammonium citrate as the sole source. B. filiformis and P. pyrenoidosa grew in media with glycine; only P. pyrenoidosa grew with histidine or urea.
The effects of fixatives on lattice bodies and filament bundles in apothecial cells of the fungus Ascobolus
Authors: Anderson R. , Zachariah K.
Published: September 2008

Lattice bodies (lattice-like aggregations of membranous tubules or vesicles) and filament bundles (extensive bundles of parallel 200-Å filaments) were first described in one cell type (medullary excipulum cells) of the apothecium of Ascobolus. Here, a detailed discussion is provided of the differential effects of three fixatives (potassium permanganate, osmium tetroxide, and glutaraldehyde) on these structures in medullary cells with reference to fixative effects on cell structure in other organisms.
Additions to the genus Arnium
Authors: Krug J. C. , Cain R. F.
Published: September 2008

Arnium Nits, in Fuckel is accepted for members of the Sordariaceae typically possessing one-celled, dark brown ascospores provided with gelatinous appendages and one or sometimes two terminal germ pores. An emended description and key are provided. Two new species are described and illustrated: A. monostichum from the United States and A. triepitheca from Canada and the United States. The following new combinations are proposed: A. absimile (Podospora absimilis Cain), A. cirriferum (Sordaria cirrifera Speg.), A. comatosporum (Podospora comatospora Cain), A. heterochaetum (Pleurage heterochaeta Griff.), A. kansense (Pleurage kansensis Griff.), and A. ontariense (Sordaria ontariensis Cain).
Dehydrogenases in a single population of the moss, Eurhynchium oreganum. The effects of dehydration and low temperature on disc electrophoretic enzyme patterns
Authors: Taylor I. E. P. , Elliott Anita M.
Published: September 2008

A single population of Eurhynchium oreganum (Sull.) Jaeg. and Sauerb. was used to examine the assumption that the wet, green, vegetative state of a moss was a stable physiological condition, and that such material may provide material suitable for chemotaxonomic studies. Disc electrophoregrams of four dehydrogenases were altered by periods of drought and cooling. Exposure to moisture gave partial reconstitution of bands after 1 or 7 days, but complete reconstitution required up to 60 days. We recommend that the time for reconstitution be determined for each species.
Abnormalities in vegetative and floral organs of Cola nitida caused by boron deficiency
Authors: Jacob V. J. , Egbe N. E. , Okoloko G. E.
Published: September 2008

Abnormalities in growth and development in C. nitida (Vent.) Schott and Endl. caused by boron deficiency are described. These include dieback of terminal shoots and the subsequent simultaneous development of many lateral branches, malformation of leaves, profuse flowering, increase in flower size, reduced fruit setting, parthenocarpic fruit development, and the preponderance of female flowers in the inflorescences. Visible deficiency symptoms did not appear when the boron content of the leaves was 15 ppm or more.
A simplified technique for automatic surface irrigation of plants in sand cultures
Authors: Dumbroff E. B. , Cooper A. W.
Published: September 2008

An automatic sand culture method that combines simplicity, economy, and versatility with the preferred technique of surface irrigation is described.
Persistence of phytochrome-mediated germination control in lettuce seeds for 1 year following a single monochromatic light flash
Authors: Vidaver William , Hsiao A. I-hsiung
Published: September 2008

The effects of red or far-red light flashes on partially hydrated lettuce seeds were found to be undiminished by subsequent dry, dark storage for more than 1 year before germination. Upon rehydration of the seeds photoreversal of the latent response could be induced by a red or far-red light flash at any time during the entire period.
Ribonucleic acid degrading activity associated with ribosomes from spinach leaf chloroplasts
Authors: Howe Richard C. , Ursino Donald J.
Published: September 2008

Ribosomes isolated from the chloroplasts of spinach leaves show the presence of RNA-degrading activity. The activity is optimal at pH 6.0 and at temperatures between 37 and 40 °C. The activity is cation-independent, exhibits exonuclease properties, and is considerably more pronounced under conditions in which the ribosome particles are in the dissociated state. The results are interpreted as showing that the RNA-degrading activity is a component part of the free ribosome population in the chloroplast.
Factors that influence dormancy in milkweed seeds
Authors: Oegema T. , Fletcher R. A.
Published: September 2008

Seeds of Asclepias syriaca L. (milkweed) have an inherent dormancy and these seeds could be forced to germinate by various treatments including stratification, cutting or removal of the seed coat, gases, alternating temperature, and a number of chemicals. Of the various treatments, the growth regulators kinetin and gibberellic acid were most effective in overcoming dormancy and a combination of these two had a synergistic effect. The increased germination percentage after 5 weeks of stratification was not accompanied by an increase in endogenous gibberellin levels. Treatment of the seeds with abscisic acid after stratification resulted in a complete inhibition of germination whereas treatment with kinetin resulted in an increase in germination. It is concluded that dormancy in milkweed seeds could be broken by many factors and regulated by an intricate interplay between growth promoters and inhibitors.
Incorporation of tritiated thymidine in tobacco pith tissues induced by a substance isolated from Ehrlich ascites fluid
Authors: Simard Antoine , Erhan Semih
Published: September 2008

A low molecular weight material isolated from ascites fluid has been found to stimulate the incorporation of tritiated thymidine in tobacco pith cells kept on a radioactive White's basic medium. The stimulatory effect is not species, order, or kingdom specific.
Growth substance requirements and major lipid constituents of tissue cultures of Euphorbia esula and E. cyparissias
Authors: Lee T. T. , Starratt A. N.
Published: September 2008

The root tissues of Euphorbia esula and E. cyparissias form callus on chemically defined medium. Both species require an exogenous supply of auxin for growth, but the appearance and color of the tissue and their responses to kinetin, 2,4-dichlorophenoxyacetic acid (2,4-D) and indoleacetic acid (IAA) are different. The tissue growth is more satisfactory with α-naphthaleneacetic acid (NAA) than with 2,4-D, IAA, or 4-amino-3,5,6-trichloropicolinic acid (picloram). Gibberellic acid has no effect. The callus tissues of E. esula become intensely green under light but are not autotrophic.Triglycerides, palmitic acid, and β-sitosterol are the major lipid constituents of the callus tissue of E. esula. Chromatographic analysis reveals no significant differences in the composition of extracts from the non-green and green tissues. Long-chain aldehydes, alcohols, and triterpenes found in the plant are not detected in the cultures.
Study on the inactivation of enzymes in Jerusalem artichoke tuber slices
Authors: Bastin Marcel , Ünlüer Osman
Published: September 2008

The formation of both peroxidase and phenol oxidase was induced by culturing slices of Jerusalem artichoke tubers under aerobic conditions at 30 °C. The rate of enzyme degradation in the tuber slices was measured after applying cycloheximide, a strong inhibitor of protein synthesis, or by culturing the tissues under anaerobic conditions. Peroxidase decayed according to a first order process with a half-life of 8.3 h while phenol oxidase was found to be more stable (half-life about 70 h). The increase in the level of enzymes after the slicing treatment was achieved through a stimulation of the rate of enzyme synthesis rather than a decrease in the rate of destruction.
Epidemiology of Scleroderris lagerbergii in central Ontario
Authors: Dorworth C. E.
Published: September 2008

Scleroderris canker (Scleroderris lagerbergii Gremmen) has damaged conifers in Europe for nearly a century. The disease has intensified in the Great Lakes region of North America during the past several decades, and the fungus could spread throughout the North Temperate Zone. Attacks by S. lagerbergii are most severe in topographical depressions and the resulting disease was thought to be associated with frost damage. Observations in depressions that resembled frost pockets indicated that extensive damage to regeneration of Pinus resinosa Ait. could be attributed primarily to amplified spore deposition in the depressions and rapid intensification of the disease in the presence of prolonged periods of high relative humidity. Topographic projections, photographs, temperature profiles, and spore collection data support this thesis. Vertical restriction to foliage within ca. 1.5 m of the ground is attributed to radiation fog that prolongs the incubation period afforded the fungus. Effects of edaphic variation, ground vegetation, and snow cover are evaluated. Snow is accorded importance in modifying extremes of winter and early spring temperatures to the advantage of the fungus. Frost damage and infection by S. lagerbergii both result in plantation failures in topographic depressions.
Promotion of stipe elongation in isolated Flammulina velutipes fruit bodies by carbohydrates, natural extracts, and amino acids
Authors: Gruen Hans E. , Wu Sheue-heng
Published: September 2008

Isolated Flammulina velutipes fruit bodies were cultured under sterile conditions with the cut base immersed in water or solutions. Stipe elongation on water was only 6% of normal for fruit bodies isolated at 1.1–2.0 cm length, 19% at 5.1–6.0 cm, and the same as for fruit bodies attached to mycelium at 9.1–10.0 cm. Fruit bodies not immersed in water grew less in a saturated atmosphere than those in water. The mycelium must supply other substances than water for normal elongation during about two-thirds of the growth period, and only water thereafter. Isolated fruit bodies fed with filtered glucose, trehalose, sucrose, or mannitol grew better than on water. Maltose and fructose increased elongation only slightly, and sorbose had no effect. Potato extract, yeast extract, and casein hydrolysate gave no or very little growth promotion, but addition of glucose strongly increased growth on the natural extracts compared to glucose alone. Of 21 amino acids added separately to glucose, only asparagine, hydroxyproline, arginine, and to a lesser extent glutamine, stimulated growth of isolated fruit bodies. Growth was not promoted by pure asparagine, glutamine, and serine, or by thiamin or indoleacetic acid. Growth was inhibited by urea, ammonium nitrate, and ammonium tartrate with or without glucose.Growth promoting substances were most effective in young fruit bodies and except for glucose the promotion disappeared in fruit bodies isolated at 6.1–7.0 cm length, which corresponds to the end of the period of rapid elongation. Apical portions of fruit bodies with caps grew better on glucose than whole fruit bodies. Growth of decapitated isolated stipes was not promoted by nutrients.
Fine structure of Oedogoniomyces zoospores, with comparative observations on Monoblepharella zoospores
Authors: Reichle R. E.
Published: September 2008

A comparison of Oedogoniomyces and Monoblepharella zoospores using electron microscopy shows that they are very similar in structure. Both have rumposomes, a striated disk, and an accessory kinetosome which had previously been thought absent in Monoblepharella. A number of other structural details are described and possible taxonomic implications are discussed.
Studies in the Arundinelleae (Gramineae). XII. Relationships of Arundinella, Jansenella, Trichopteryx, and the danthoniopsoids
Authors: Phipps J. B.
Published: September 2008

This study details the results of phenetic taxonomic studies, using morphological data, on a small group of genera and a major group whose interrelationships had been, in the past, confused. The results indicate Arundinella to be a large, homogeneous, and well-moated genus. Jansenella, its single species previously described under Arundinella, Danthoniopsis, and other genera, is now continued as a well isolated monotypic. The danthoniopsoid group is well isolated from Arundinella and Jansenella but it intergrades through Petrina parva to the trichopterygoids. Trichopteryx is well isolated from Arundinella and Jansenella but on one edge is close to the danthoniopsoids. Gilgiochloa, a monotypic danthoniopsoid, is highly isolated.
The fine structure of corn phloem
Authors: Singh A. P. , Srivastava L. M.
Published: September 2008

The differentiation of sieve elements, companion cells, and vascular parenchyma in leaf bundles of corn is described. The sieve elements have plastids with distinctive crystalline inclusions, lack P-protein, and have nacreous walls in which the predominant orientation of microfibrils seems to be at right angles to the length of the cell. The companion and vascular parenchyma cells have numerous, well-developed mitochondria. These and other results are discussed in relation to long distance transport in the sieve elements.
Localization of neutral red in lysosome structures in hair cells of Tradescantia virginiana
Authors: Mahlberg Paul
Published: September 2008

Neutral red accumulates in membraned structures associated with the peripheral cytoplasm that correspond to secondary vacuoles in morphology and movement. Different secondary vacuoles show some variation in color intensity indicating variability in their pH value, which suggests that physiological differences exist between these structures. Secondary vacuoles, therefore, appear to represent a distinctive lysosome which characterizes plant cells.
Genera coelomycetarum. IV. Pseudorobillarda gen. nov., a generic segregate of Robillarda Sacc.
Authors: Raj T. R. Nag , Morgan-Jones G. , Kendrick Bryce
Published: September 2008

A new genus, Pseudorobillarda, is proposed to accommodate four species, namely P. bambusae sp. nov., P. indica sp. nov., P. agrostidis (Sprague) comb. nov., and P. phragmitis (Cunnell) comb. nov. The last two species were previously placed in Robillarda Sacc. It is suggested that Robillarda celtidis Scalia may belong in Pseudorobillarda.
Environmental factors regulating the production of conidia by sclerotia of Botrytis convoluta
Authors: Jackson R. S.
Published: September 2008

Sclerotia of Botrytis convoluta germinated to produce conidia only when dried, remoistened, and exposed to near-ultraviolet (n.uv.) radiation. An exposure of less than 2 h at an intensity of 340 μW/cm2 was ineffective in inducing spore production. Longer exposures, up to 45 h duration, progressively resulted in greater sporulation. Sensitivity to n.uv. radiation fell when sclerotia were held under moist conditions in darkness for more than 12 h. The development of the loss of sensitivity was retarded for at least 24 h by exposing sclerotia to n.uv. radiation for 30 min at an intensity of 340 μW/cm2. Induction of sporulation by n.uv. radiation was optimal at 20 °C. Initiation of conidiophore formation appears to be optimal at 5 °C. Conidial production was not influenced by holding the sclerotia at either 5 or 15 °C.
The effect of cupric and fluoride ions on the respiration of Chlorella
Authors: Sargent D. F. , Taylor C. P. S.
Published: September 2008

The respiration rate of endogenously respiring Chlorella pyrenoidosa is not decreased by 4.10−2 M fluoride or 8.10−3 M cupric ions, but when both agents are added simultaneously oxygen uptake stops immediately. Parallel experiments with glucose-stimulated cells lead us to conclude that copper alone does not inhibit a dissimilation pathway distinct from glycolysis, as has previously been suggested. We propose an explanation of the decreased inhibition found when F− is added before Cu2+, based on our finding that the inhibition of glycolysis by F− decreases with time.
Sulfur nutrition of Puccinia graminis f. sp. tritici in axenic culture
Authors: Howes N. K. , Scott K. J.
Published: September 2008

The amino acid requirements of subcultures of the wheat stem rust Puccinia graminis f. sp. tritici have been determined. These isolates will grow on an agar solidified medium containing Czapek's minerals, glucose, citrate, cysteine, and one of the following nitrogen sources: ammonium, aspartate, asparagine, glutamate, glutamine, alanine, serine, and glycine, but not nitrate or nitrite. Cysteine can be replaced by homocysteine or methionine, but not by inorganic forms of sulfur. Possible reasons for the requirement of these organic sulfur compounds are discussed.
The development and growth requirements of Dactylorhiza purpurella in asymbiotic cultures
Authors: Harvais Gaëtan
Published: September 2008

Dactylorhiza purpurella was grown from seed in sterile cultures on agar slopes. The culture media consisted of combinations of minerals, dextrose or sucrose, the amino acids and vitamins etc. found in casein hydrolysate, and yeast extract. After an initial period of germination and growth, the cultures were treated with kinetin, kinetin riboside, 6(γ, γ-dimethylallylamino)purine, and indoleacetic acid (IAA), alone and in various combinations, primarily to simulate patterns of development previously obtained in symbiotic cultures.The results with dextrose and sucrose were essentially similar. Germination and growth in either case were markedly superior where casamino acids were present, and growth and survival were further improved with supplements of yeast extract to those media. On such media protocorm development was normal and in every respect as good as in symbiotic cultures. Aspartic, glutamic, and nicotinic acids appear to play vital roles in the nutrition of D. purpurella.The three aminopurines tested enhanced the shoot characters and suppressed the root characters of the protocorms, and enhanced chlorophyll formation. The results with IAA were inconclusive. The growth regulators may interact with aspartic and (or) glutamic acids with respect to morphogenesis.Iron (as ammonium ferric citrate) was deficient and limiting at 0.2 mg/liter Fe. Greener shoots, better rooting, and no harmful effects were obtained with 25 mg/liter. High levels of manganese (50 mg/liter) caused severe leaf chlorosis and hindered the beneficial effects of iron on the shoots. An Fe/Mn ratio greater than unity was necessary. Within certain limits, the right ratio may be more important than the actual levels of these cations.The effects of the growth regulators should be reassessed in relation to at least aspartic and glutamic acids, iron and manganese.
Two peroxidases isolated from kidney bean cell suspension cultures
Authors: Misawa M. , Martin S. M.
Published: September 2008

Two peroxidases, isolated from filtrates of suspension cultures of a cell line derived from red kidney bean (Phaseolus vulgaris) were purified 145- and 72-fold respectively. The two enzymes were quite similar in many of their properties and both were typical plant peroxidases. They differed markedly, however, in their molecular weights (estimated by gel filtration). The molecular weight of peroxidase I was 30 000 whereas that of peroxidase II was only 6000.
Ultrastructure of Ustilago hordei. I. Pregermination development of hydrating teliospores
Authors: Robb Jane
Published: September 2008

An attempt has been made to determine the sequence of cytological changes occurring during the uptake of water by ungerminated teliospores of Ustilago hordei. The first detectable changes are an increase in the amount of endoplasmic reticulum, the development of patches of "foamy cytoplasm," and a peculiar amoeboid activity of the nucleus. Shortly after, vacuoles begin to appear in the central regions of the protoplast. The mitochondria increase in size throughout the pregermination period but show no evidence of division until shortly before germination. Lipid does not seem to decrease substantially. Hypotheses are put forward to account for the origin of the endoplasmic reticulum and of "primary vacuoles."
The effect of Kraft pulp mill effluents on the growth of Zalerion maritimum
Authors: Churchland L. M. , McClaren M.
Published: September 2008

Growth of the marine fungus Zalerion maritimum was measured in Kraft pulp mill effluents. The effluents used were caustic effluent, acidic effluent, and acidic effluent adjusted to pH 8. The effluent and the seawater control flasks were supplemented, in some instances, with basal nutrients. Two concentrations of effluent, 50% (50% effluent, 50% seawater) and 100%, were used.When basal nutrients were added, dry weight was significantly greater (95% probability level) in 100% caustic effluent than in 50% caustic effluent or seawater alone. Without basal nutrients, growth was lower in 100% caustic effluent than in seawater or 50% effluent. This suggests that growth of Z. maritimum would not be stimulated by Kraft effluent under field conditions.Unlike the caustic effluent, the acidic effluent inhibited growth of Z. maritimum. With added nutrients, growth was lower in 50% and 100% acidic effluent than in seawater. When the acidic effluent solutions were adjusted to pH 8, growth was lower than in the seawater medium.
Color mutants in Cochliobolus carbonum
Authors: Leonard K. J.
Published: September 2008

One spontaneous and 31 ultraviolet-induced albino mutants of apparently independent origin of Cochliobolus carbonum Nelson were shown to be alleles or, at least, very closely linked. One spontaneous and one ultraviolet-induced mutant at a second locus conditioned the production of brown rather than black conidia. A third type of mutant induced by ultraviolet (uv.) irradiation produced visible quantities of a diffusible, lavender pigment. The lavender locus appeared to be loosely linked to the albino (40 crossover units) and the brown conidia (38 crossover units) loci. The mating type alleles segregated independently of the three loci affecting color.Albino mutants produced fewer and less well-developed perithecia in matings than did the wild-type isolates from which they were derived. Perithecia of the brown conidia mutants could not be distinguished from wild-type perithecia.
Fluctuations in the inorganic constituents of inner bark of loblolly pine with season and soil series
Authors: White Jerry D. , Alexander L. T. , Clark E. W.
Published: September 2008

The concentrations of K, Ca, N, Mg, P, Al, Mn, Na, Zn, Fe, Cu, ash, and H2O in the inner bark of mature loblolly pines growing on three soil series were determined over a 1-year period. Concentrations of ash, H2O, Ca, Al, Mn, and Fe differed significantly among the trees on the three soil types. Most elements reached maximum concentrations in the fall and minimum concentrations in the spring. Ash, H2O, Mg, Mn, Zn, and Fe showed significant seasonal fluctuations. Because spring is a period of rapid transitions, late summer seems the most stable period in which to sample tissues from inner bark.
Studies in the Arundinelleae (Gramineae). XIV. Taximetrics of a reduced character set
Authors: Phipps J. B.
Published: September 2008

This paper studies the effects of using only 65 reproductive characters on the classification of 164 OTUs of the tribe Arundinelleae (Gramineae). The following taxa and groups can be recognized, some of which permit of further generic splitting: Arundinella, Jansenella, Gilgiochloa, Danthoniopsis sensu lato, Trichopteryx, Loudetia, Tristachya sensu stricto; a group containing Dolichochaete, Apochaete and Isalus; Veseyochloa; and a group containing Zonotriche sensu stricto. Other named taxa are either not very homogeneous or less strongly isolated. These include Muantijamvella, Piptostachya, Loudetiopsis sensu stricto, Diandrostachya, and Dilophotriche.Few of the Arundinella series are recognizable, neither are the subsections of section Loudetia of Loudetia. Characteristics of importance are those well known to separate the danthoniopsoid, tristachyoid, and loudetioid groups. They include those of the palea of the upper floret, color of the spikelet, ovary pubescence, shape of awn in cross section, and characters of the length and shape of glumes and lemma of lower floret, among others.The overall classification corresponds most strongly to earlier ones of Phipps, though the deletion of vegetative characters obscures the danthoniopsoid segregate genera and emphasizes Dilophotriche. With respect to Clayton's numerical taxonomy, differences are most marked in the treatment of the tristachyoid genera and Loudetiopsis sensu lato. It is clear that these differences relate to the different character suites chosen. Arguments are developed to indicate that, in one case at least, Clayton's approach of deliberately selecting useful characters is less sound than the present author's more empirical approach. The discussion presented in this paper strongly underlines the dilemma facing the systematist in choosing characters.
Genetic implications of current models of somatic nuclear division in fungi
Authors: Day Alan W.
Published: September 2008

The unusual two-track type of division which is widespread in most fungi other than Phycomycetes is described. Three models which attempt to account for this type of division are discussed in relation to (i) genetical observations on somatic segregation and (ii) chromosome distribution studies which predict that chromosomes of similar genetic 'age' move as a set. The feasibility of two of the models which postulate that the chromosomes are linked in chains is discussed in the light of our knowledge of mitotic crossing-over and haploidization. The third model (Robinow and Caten 1969) is more orthodox and differs from classical mitosis only in the presence of a narrow intranuclear spindle around which the chromosomes attach randomly and disjoin asynchronously. Future experimental approaches to distinguish between these models and to define the mechanism of division more completely are suggested.
Ontogeny of the vegetative and floral apex of Calycanthus occidentalis
Authors: Dengler N. G.
Published: September 2008

The early ontogeny of the flower of Calycanthus occidentalis is described. The pattern of initiation, procambial development, apical growth, and marginal growth of floral bracts and tepals is similar to that of the leaf, while stamens, staminodia, and carpels are not leaf-like in some aspects of their development. The initiating periclinal divisions of staminodia and carpels occur in the third and fourth layers from the surface and procambium development in the carpel is discontinuous and bidirectional. These similarities in development to some axillary buds are probably due to the position of the young primordia which are isolated from developing procambial strands by parenchyma tissue. The concave floral cup is formed through the activity of an intercalary meristem concurrently with the early stages of appendage ontogeny.
Isolation of Thielaviopsis basicola from soil with umbelliferous root tissue as baits
Authors: McIlveen W. D. , Edgington L. V.
Published: September 2008

Root tissue of 31 cultivars and varieties representing 12 species and 12 genera of the Umbelliferae were tested and evaluated as baits for Thielaviopsis basicola (Berk. & Br.) Ferr. in soil. The relative ability of root tissue of each species to selectively bait T. basicola from soil was measured as degree of invasion of the root tissues by T. basicola and freedom of the tissue from decay by other organisms. Root tissue of carrot as bait was superior to root tissue of other species tested. The mechanism(s) in carrot which permits selective isolation of T. basicola from soil is not restricted to carrot but can be found in varying degrees in at least five other species in the Umbelliferae.
Sites of photosynthetic metabolism in cells and chloroplast preparations of Acetabularia mediterranea
Authors: Winkenbach F. , Parthasarathy M. V. , Bidwell R. G. S.
Published: September 2008

Chloroplast preparations from Acetabularia mediterranea were shown to consist mainly of small droplets (2–10 μ) containing some cytoplasm and surrounded by a membrane. An analysis was made of the contribution of the cytoplasmic contamination to photosynthetic metabolism. It is concluded that the majority of the photosynthetic metabolism observed takes place in the chloroplasts, but the degree to which it may be influenced by the presence of cytoplasm cannot be determined. Sucrose synthesis takes place in chloroplast preparations, and possibly in chloroplasts themselves, but its subsequent metabolism to monosaccharides or fructosan requires the organization of whole cells. It seems probable that fructosan synthesis and storage is associated with or in the vacuole.
Studies on the daily course of carbon exchange in alfalfa plants
Authors: Pearson C. J. , Hunt L. A.
Published: September 2008

The diurnal pattern of carbon dioxide exchange is described for plants of cultivars Vernal and Moapa alfalfa (Medicago sativa L.) grown at day/night temperatures of 30/25C and 20/15C, an irradiance of 25 nanoEinsteins cm−2 s−1 (400–700 nm), and a day length of 15.5 h. The net carbon dioxide intake (NCI) of the tops reached 90% of its maximum value after 4–5 h of illumination at 20/15C, but after only 1–2 h at 30/25C; by contrast, NCI of the tops declined after 11–14 h from the start of the photoperiod at 20/15C and after 8.5–10.5 h at 30/25C. Net carbon dioxide output (NCO) of the tops increased throughout the dark period at 20/15C, but remained constant at 30/25C. NCO of the roots remained constant throughout the photoperiod at 20/15C, and increased linearly for 4–8 h at 30/25C. Similarly, NCO of the roots remained constant throughout the dark period at 20/15C, but changed with time (decreased) at 30/25C.
Notes on the habitat and distribution of Avena species in the Mediterranean and Middle East
Authors: Baum B. R. , Fleischmann G. , Martens J. W. , Rajhathy T. , Thomas H.
Published: September 2008

Brief descriptions of the habitats and distributions of Avena species in the Mediterranean and Near East areas are given. These are based on observations made by the authors in three expeditions undertaken during the last decade.Avena pilosa, at its highest distributional density, is a primary component of the Quercus brantii climax area. The main concentration of A. clauda is in the Pistacia–Amygdalus steppe forest which is usually adjacent to the former species. Avena clauda is also a weed in some places in Iran. Both A. pilosa and A. clauda form large populations in Turkish and Iraqui Kurdistan and Iran but small and scattered populations in the Mediterranean region. Avena ventricosa is a rare and scattered species; it is probably of a relic nature and is found only in undisturbed habitats. Avena longiglumis is primarily a Mediterranean species and prefers light or sandy soil. The aggregate A. hirtula–wiestii is Arabo–Nubian–Mediterranean, and forms dense colonies. Avena barbata is Mediterranean – West Irano – Turanian and it is a common weed in all of the Mediterranean area. Avena sterilis is the most common species, and is also the most aggressive weed among oat species from Afghanistan to the Atlantic coast. Avena sterilis is a component of many East Mediterranean – West Irano – Turanian associations with oaks, or shrubs such as Poterietum spinosum. Avena fatua is rare in the areas explored by the authors, but it did occur as a weed of cultivation in areas under strong steppical or continental conditions, such as in northwestern Iran or eastern Turkey. Avena sativa–byzantina aggr. is a weed of cereals in the Mediterranean area, and it is grown as a cereal in northwestern Turkey and northwestern Iran.
Malus tissue cultures. I. Sorbitol (D-glucitol) as a carbon source for callus initiation and growth
Authors: Chong Calvin , Taper C. D.
Published: September 2008

Callus cultures from 1-year-old twigs of the apple, Malus pumila, cultivars McIntosh, Cortland, and Red Delicious, and of the crabapple rootstock, Malus robusta No. 5, were successfully isolated and maintained on a medium with sorbitol as the sole carbon source. Investigation with various carbon sources, each at 3% concentration, showed that McIntosh callus grew equally well on sorbitol, sucrose, and glucose. Cortland and Robusta cultures responded equally to sorbitol and glucose but poorly to sucrose. The relative growths of the callus cultures on sorbitol were in the decreasing order, McIntosh, Cortland, and Robusta. Sorbitol served as an excellent carbon source for all three cultures.