bluuebunny/crossref_metadata_2025 huggingface dataset:
Frost tolerance of Liquidambar styraciflua native to the United States, Mexico, and Central America
Authors: Williams, III George J. , McMillan Calvin
Published: September 2008

Seedlings derived from field-collected seed from the United States, Mexico, and Central America were tested for frost hardiness under laboratory conditions. U.S. seedlings grown under four controlled conditions demonstrated greatest frost hardening under cool temperatures and short day lengths. Seedlings representing northernmost U.S. collection sites developed greater frost tolerance than seedlings representing southern U.S. collection sites. In comparing United States, Mexico, and Central America seedlings, the U.S. material showed greatest frost tolerance with Mexico and Central America demonstrating similar hardiness. The application of plant hormones (natural gibberellic acid and artificial AMO-1618) produced opposite effects on U.S. seedlings derived from Connecticut and Florida seed. The Connecticut seedlings demonstrated greatest frost tolerance in all treatments. Demonstrated frost tolerance differences among United States, Mexico, and Central America populations strongly indicate selection of frost hardy races in habitats with severe frost conditions.
A chromatographic and cytological study of Dryopteris filix-mas and related taxa in North America
Authors: Widén C.-J. , Britton D. M.
Published: September 2008

Chromatographic analyses of the phloroglucinol derivatives of 86 collections comprising Dryopteris filix-mas (L.) Schott (4x), D. arguta (Kaulf.) Watt (2x), D. marginalis (L.) A. Gray (2x), and the hybrids D. filix-mas × marginalis (3x), D. cristata × marginalis (3x), D. goldiana × marginalis (2x), and D. intermedia × marginalis (2x) in North America is presented. Material of D. filix-mas from the West differed from that collected in the East. The western material was rich in filixic acid, and had a chromatographic spectrum similar to European D. filix-mas s. str. D. marginalis is lacking filixic acid, and is not closely related to D. filix-mas based on chromatographic evidence. Methylene-bisaspidinol, a compound not previously found in Dryopteris, was isolated from D. marginalis. D. arguta contains filixic acid, and has a chromatographic pattern close to that of D. abbreviata (DC.) Newman, which in turn is one of the ancestors of D. filix-mas s. str. in Europe. The influence of D. marginalis in the phloroglucinol spectrum of the interspecific hybrids studied was very strong except in the hybrid D. filix-mas × marginalis.
The initial protrusion of a leaf primordium can form without concurrent periclinal cell divisions
Authors: Foard Donald E.
Published: September 2008

The view that periclinal cell divisions cause the initial protrusion of a leaf primordium may be tested by using ionizing radiation to prevent cell divisions without preventing growth. After receiving 800 krad of gamma rays, wheat grains containing embryos with three leaf primordia produce seedlings in which a fourth protrusion of the shoot apex forms unaccompanied by cell divisions. This protrusion without periclinal divisions occurs in the same phyllotactic position as that of the fourth leaf primordium in which periclinal divisions occur. In addition to proper phyllotactic position, the protrusion without cell divisions is formed by the outermost cell layer, as is the initial protrusion of a typical leaf primordium of wheat; moreover, the initial number of cells involved is the same in both kinds of protrusions. Therefore the fourth protrusion in seedlings from irradiated grain is interpreted as the initial protrusion of a leaf primordium that formed without periclinal cell divisions. Measured along the axis of greatest extension, the protrusions without cell divisions represent about a four- to eight-fold increase over the anticlinal dimension of the surface-cell layer in the embryo. These protrusions do not develop further. The absence of cell divisions limits the extent of primordial growth, but does not prevent its inception. Periclinal cell divisions do not cause the initial protrusion of a leaf primordium.
The occurrence of Phlyctidium scenedesmi on Pediastrum boryanum and Scenedesmus quadricauda in School Bay of the Delta Marsh
Authors: Masters Margaret J.
Published: September 2008

Phlyctidium scenedesmi Fott, a parasite of Scenedesmus quadricauda, was observed on this host and on Pediastrum boryanum in School Bay of the Delta Marsh during the summers of 1966, 1967, and July 1968. During the summer of 1966 the fungus simultaneously attacked both host populations. Despite the fact that the algae were multiplying rapidly, the fungus was able to attack and kill host cells. At the time of the fungus maximum on July 24, 43% of the Pediastrum coenobia and 46% of Scenedesmus coenobia supported fungus thalli. Thereafter, the host populations and the chytrid declined. Scattered chytrid thalli were observed on the low algal populations, however, even as late as October 9. During 1967, neither alga was as abundant as the year before and infection by P. scenedesmi was sparse too. In 1968, both Pediastrum and Scenedesmus achieved large maxima, but Phlyctidium was observed briefly only at the beginning of July.
Cyathus crassimurus sp. nov. from Hawaii
Authors: Brodie Harold J.
Published: September 2008

Cyathus crassimurus sp. nov. from Hawaii is described, illustrated, and compared with C. pallidus and C. intermedius.
Cyathus pictus, a large-spored bird's nest fungus from Mexico
Authors: Brodie Harold J.
Published: September 2008

A hitherto unnamed species of Cyathus is described as C. pictus. In form, the species resembles C. stercoreus, which it also resembles in the possession of very large globose spores. C. pictus differs markedly from C. stercoreus in lacking the long external hairs of the latter and in possessing a reddish band just below the outside of the peridium mouth.
Organelle distribution and cell differentiation in the formation of stomatal complexes in barley
Authors: Zeiger Eduardo
Published: September 2008

Interference – phase contrast observations of leaf epidermis in barley revealed the arrangement of organelles in cells that form stomatal complexes. Organelle movement and alignment were highly correlated with the process of cell division and differentiation that leads to mature stomata. Organelle rearrangement was most marked at the asymmetrical divisions that formed subsidiary cells of stomatal complexes.
The occurrence of Phlyctidium bumilleriae on two growth forms of Staurastrum pinque and other Staurastrum spp., in Lake Manitoba
Authors: Masters Margaret J.
Published: September 2008

Phlyctidium bumilleriae Couch was observed attacking Staurastrum pinque, S. chaetoceros, S. muticum, and S. cuspidatum var. divergens in Lake Manitoba during the summers of 1965–1968. S. pinque, the host present in the greatest numbers in the phytoplankton, occurred in a three-radiate, a four-radiate, and an intermediate growth form with three radii on one semicell and four on the other. Both in 1966 and 1967 the four-radiate form was more heavily attacked by Phlyctidium than the three-radiate form although the latter was present in greater numbers. In July 1968, it was the four-radiate form which was more numerous but still it was this form which Phlyctidium most heavily attacked. Intermediate cells succumbed to the fungus in proportions similar to the four-radiate form.
Regulation of isocitrate lyase from autotrophic and photoheterotrophic cultures of Gloeomonas sp.
Authors: Foo S. K. , Badour S. S. , Waygood E. R.
Published: September 2008

Isocitrate lyase (EC. 4.1.3.1) has been partially purified from extracts of the unicellular green alga Gloeomonas sp. grown either photoautotrophically in CO2 or photoheterotrophically with acetate resulting in a 50-fold increase in specific activity. Enzyme preparations from both cultures were eluted from DEAE-cellulose columns at almost the same position. The enzymes showed classical Michaelis kinetics with Km values of 1.14 and 1.4 mM and responded in a similar manner to metabolites. Glycol-late, 3-phosphoglycerate, ribulose diphosphate, α-ketoglutarate, succinate, malate, fumarate, and ADP inhibited the enzyme at concentrations of 10 mM. Inhibition by oxaloacetate occurred at 1 mM. Succinyl-CoA (1 mM) activated the enzyme to 155% of the control. These results are discussed in relation to the autotrophic and photoheterotrophic mode of nutrition in algae.
Light-suppressed germination of California poppy seed
Authors: Goldthwaite Jonathan J. , Bristol Joanna C. , Gentile Arthur C. , Klein Richard M.
Published: September 2008

Germination of California poppy seed was suppressed by white light from fluorescent and incandescent lamps. Seeds were most sensitive to light-suppression of germination during a period between 8 and 12 h from start of imbibition. Far-red, red, and blue wavelength bands were suppressive with far-red being most effective. Although they interacted, photoreversibility of red and far-red radiations did not occur. Addition of nitrate ion or of kinetin increased suppressive effects of far-red and of red radiations. Gibberellic acid relieved suppressions of germination induced by continuous radiation.
Notes on eight species of Coprinus of the Yukon Territory and adjacent Alaska
Authors: Watling Roy , Miller Jr. Orson K.
Published: September 2008

Eight species of Coprinus, including C. atramentarius, C. comatus, C. exstinctorius, C. micaceus, C. narcoticus, C. patouillardii, C. radians, and C. subimpatiens are recorded from the St. Elias Mountains and near Kluane Lake in the Yukon Territory, the Skolai Pass in the Alaskan Range, and the vicinity of Juneau, Alaska.
Seasonal change in the shoot flora diversity of hardwood forest stands on Mont St. Hilaire, Quebec
Authors: Holland P. G.
Published: September 2008

Diversity, in the various senses in which the term is used by plant ecologists, is shown to vary with time of year in each of four stands in the northern hardwood forest region of southern Quebec. The lowest values were obtained in winter and the highest in summer. Much of the variation in diversity over the year can be explained by changes in the numbers of plant species, present as shoots, in a stand: this is particularly the case in the late spring and summer months, but rather less so in the fall. Analysis of the simply collected, and reliable, presence/absence sample data gives as satisfactory an account of seasonal trends in shoot flora diversity as does analysis of the more usually consulted abundance data. It is concluded that many of the formal notions of succession studies may apply to the more restricted case of seasonal change in vegetation composition and structure.
Hormonal interaction in controlling apical dominance in soybeans
Authors: Ali A. , Fletcher R. A.
Published: September 2008

Growth of cotyledonary buds in soybean plants is controlled by an interaction between hormones and is dependent on age of the plant and meristematic activity of the buds. Indoleacetic acid (IAA) applied to the cut surface of decapitated 7-day-old plants does not inhibit the growth of buds which are actively undergoing mitosis. Growth is inhibited, however, when IAA is applied in combination with benzyl-adenine(BA) and this inhibitory effect is minimized by gibberellic acid (GA). In 16-day-old plants where mitosis in the buds has ceased IAA alone inhibits bud growth. In both 7- and 16-day-old decapitated plants, application of GA, alone or in combination with BA promotes growth of the buds. Inhibited buds have two peroxidase isoenzymes with pronounced activity. The activity of one of these decreases when the buds are released from dominance. Benzyladenine applied directly to inhibited buds initiates growth in 16-day-old intact plants and this growth is further enhanced when GA is applied 48 h after BA treatment. The enhanced growth by GA is prevented if 5-fluorouracil (5-FU) or 5-fluorodeoxyuridine (5-FDU) are applied before but not after the GA treatment. These results indicate that the hormones have a sequential role in releasing buds from apical dominance.
Changes in the nitrogenous components of maturing rapeseed (Brassica napus)
Authors: Finlayson A. J. , Christ C. M.
Published: September 2008

Changes in seed nitrogen content, seed weight, precipitatable nitrogen (protein) content of maturing rapeseed show that there is a greater increase in precipitatable nitrogen during the early stages of seed development than at the later stages. Proteins found in the mature seed, however, are not detected until the last 3 weeks of seed growth. The deposition or completion of synthesis of the storage proteins apparently occurs over a 14-day period in rape.
Effects of direct contact of Pinus resinosa seeds and young seedlings with 2,4-D or picloram on seedling development
Authors: Wu Ching Chen , Kozlowski T. T. , Evert R. F. , Sasaki S.
Published: September 2008

Effects of 2,4-D and picloram at 50 and 100 ppm on early development of Pinus resinosa seedlings were studied. Both herbicides caused abnormal development of pine seedlings. After seeds germinated, the first conspicuous effect of 2,4-D treatment was cessation of root elongation. Proliferation and expansion of parenchyma cells in the stem and cotyledons were also stimulated by 2,4-D, causing abnormal thickening of seedlings. Disorganization and collapse of parenchyma cells in the upper stem were followed by callus formation. Cotyledons of 2,4-D-treated plants developed abnormally. Formation of vascular strands was retarded. Division and expansion of mesophyll cells were stimulated by 2,4-D causing decrease in intercellular spaces. Numbers of stomata and chloroplasts were lower in cotyledons of treated plants than in controls. Cotyledons of treated plants were fused to primary needles. Expansion of early formed primary needles and initiation and expansion of additional primary needles were inhibited by 2,4-D. Effects of picloram on pine seedlings were somewhat similar to effects of 2,4-D but picloram appeared to be more toxic at comparable dosages.
Distribution of certain soil inhabiting chytrid and chytridiaceous species related to some physical and chemical factors
Authors: Booth Tom
Published: September 2008

Most ecological studies of chytrids and chytridiaceous fungi in soils are primarily distributional, and autecological information for particular species is scant. In this study the distribution of 11 species, Schizochytrium aggregatum, Thraustochytrium roseum, Chytriomyces hyalinus, Rhizophlyctis harderi, Rhizophydium sp. (utriculare?), R. sphaerocarpum, R. carpophilum, R. sphaerotheca, Phlyctochytrium chaetiferum, P. palustre, and P. reinboldtae, is numerically expressed by an index (DII) derived from occurrence and frequency for 19 habitats. Mean values of various environmental parameters—pH, organic matter, bulk density, osmolarity, Ca2+, Mg2+, and Na+—are calculated for each habitat, and linear correlations of DII against means of the environmental factors of each habitat are calculated for each species. Also the range, mean, and standard deviation of chemical and physical parameters at sites where each species occurs are calculated. By these methods some autecological facts appear for each species. Basically the fungi are divisible into four groups: (1) obligately marine, S. aggregatum; (2) marine, T. roseum; (3) facultatively marine, C. hyalinus, R. harderi, R. sphaerocarpum, P. chaetiferum, R. carpophilum, R. sphaerotheca, Rhizophydium sp. (utriculare?); and (4) marine occasionals, P. palustre, P. reinboldtae. Problematic aspects of the study are discussed and another line of investigation is proposed.
Ecotypic responses of chytrid and chytridiaceous species to various salinity and temperature combinations
Authors: Booth Tom
Published: September 2008

Temperature and salinity responses of 57 isolates of various taxa of the Chytridiales and Blastocladiales were determined after maintenance of isolates under controlled conditions for a minimum period of 6 months. Differences and similarities among isolates generally seem constant in time and over several isolates of the same species from the same collection. Since these differences and similarities within a species tend to correlate with habitat types, they possibly represent ecotypes.
The site of cyanide inhibition of sugar translocation in sugar beet leaf
Authors: Ho L. C. , Mortimer D. C.
Published: September 2008

The translocation of 14C-assimilate in sugar beet can be stopped at the top of the petiole when cyanide (pH 7,0.5 M) is applied to the petiole about 12 cm from the base of the blade 3 min before the 14CO2 assimilation. Such an inhibition persists for at least 50 min. The possible retarding effect of cyanide on photosynthesis, the loading process of sugar into the venation, and movement of sucrose along the conduit have been investigated by chromatographic analyses of the photosynthetic products and by radioautography of the 14C movement in the leaf blade. The cyanide moves rapidly upward from the point of application in the petiole, but does not affect the photosynthetic or loading processes in the leaf blade. The results suggest that a cyanide-sensitive mechanism located in the phloem tissue along the conducting pathway is essential to maintain the normal rapid movement of assimilate from the source to the sink.
Studies on the origin of amylose and amylopectin in starch granules. III. The effect of temperature on enzyme activities and amylose content
Authors: Mangat B. S. , Badenhuizen N. P.
Published: September 2008

Starch composition (amylose content) and the activities of starch-synthesizing enzymes were determined in cultures of Polytoma uvella and potatoes kept at various temperatures. In general ADPG-α-glucan glucosyltransferases were much less thermostable in vivo than P- and Q-enzymes. Potato phosphorylase proved to be the most stable enzyme. In Polytoma both P/Q ratio and amylose content decreased at 30 °C, whereas they remained unchanged in potatoes grown at 30 °C. This confirms the results from earlier experiments which indicated that the P/Q ratio is correlated with amylose content, and is also in agreement with the simultaneous increase in amylose percentage and P/Q ratio observed during the development of starch granules in corn endosperm. The results are discussed in relation to the problem of amylose production in starch granules and the importance of phosphorylase in starch synthesis.
Chromatographic studies in the Sagittaria graminea complex
Authors: Wooten Jean W.
Published: September 2008

Leaf extracts of three highly variable, heterophyllus varieties of S. graminea were studied using two-dimensional paper chromatography. Inter- and intra-population variation in phenolic patterns were analyzed and compared with statistical analyses of morphological variation. Infraspecific chemical variation showed a high correlation with previously established ecotypic differentiation of taxa. Individual plant phenolic patterns of phyllodial, submersed leaves differed from those of emersed leaves, indicating that environmental parameters modify production of phenolic compounds. Since ecotypic differentiation in all taxa within the complex is not detectable by morphological characters, a possible explanation for the lack of correlation between morphological and chemical evidence is discussed.
A chemosystematic study of the Caprifoliaceae
Authors: Bohm Bruce A. , Glennie C. Wm.
Published: September 2008

The phenolic compounds in leaf material of 52 taxa of the Caprifoliaceae representing 11 genera have been examined. The cyanogenetic glycoside sambunigrin was found to occur only in certain members of Sambucus. Chlorogenic acid isomers and simple phenolic acids were identified in all taxa examined; coumarins were of more limited distribution. The flavonols kaempferol and quercetin, considered to be primitive chemical types, occur most frequently in Viburnum, Sambucus, and Weigela. The flavones apigenin and luteolin, more advanced types, are predominant in Symphoricarpos, Triosteum, and Lonicera. Amentoflavone, a biflavonyl derivative, has been found in two species of Viburnum, substantiating an earlier report of its existence in this genus. This is also taken to represent a primitive chemical type which supports the contention that Viburnum is one of the more primitive genera in the family. A number of other relationships within the family are discussed in light of the chemical data.
Timing and rate of bud formation in Pinus resinosa
Authors: Sucoff Edward
Published: September 2008

During the 1969 and 1970 growing season buds were collected almost weekly from matched trees in northeastern Minnesota. Cataphyll primordia for the year n + 1 shoot began forming at the time that internodes in the year n shoot started elongating (late April) and continued forming until early September. Primordia for axillary buds started forming about 2 months later and stopped forming at the same time as cataphylls. The size and deposition activity of the apical dome simultaneously increased during the early growing season and decreased during the late season. The maximum rates in July were over nine cataphylls per day.Rate of cataphyll deposition paralleled elongation of the needles on subtending shoots. Forty to fifty percent of the cataphylls had been formed when shoot growth was 95% complete. Although the bulk of the depositions occurred earlier in 1970, when growing degree days were used as the clock, the 2 years were similar.The results provide quantitative data to complement the histologic emphasis of previous studies.
Seed production and dormancy in Rumex crispus. II. The effects of removal of various proportions of flowers at anthesis
Authors: Maun M. A. , Cavers P. B.
Published: September 2008

Systematic removal of 25, 50, and 75% of the flower whorls from panicles of Rumex crispus L. (curled dock) reduced the total yield per panicle of seeds and fruits in comparison to control plants. However, the mean weight per seed was progressively higher as a greater proportion of the whorls was removed.For untreated plants, seeds borne toward the tips of branches were always lighter than those found near the junctions of branches with the main rachis. Seeds from the lower portion of the panicle were generally larger than those from the upper branches. On treated plants individual seed weight became less variable over the whole panicle.Although seeds from all treatments were equally viable, the larger seeds from treated plants exhibited a greater amount of dormancy under several germination regimes. This increased dormancy might be attributed to the thicker investing structures of larger seeds.
Development of chlamydospores in Verticillium nigrescens and V. nubilum
Authors: Hoes J. A.
Published: September 2008

Development, position, septation, color and size of chlamydospores, and temperature response of V. nigrescens and V. nubilum is described. The affinities of the two species to other fungi are discussed.
On Holwaya, Crinula, Claussenomyces, and Corynella
Authors: Korf Richard P. , Abawi George S.
Published: September 2008

A monographic investigation of the genus Holwaya Sacc. leads to acceptance of a single species, H. mucida (Schulzer) comb, nov., for which a longer-spored variant from Japan, H. mucida subsp. nipponica subsp. nov., is described. The prominent stilbaceous imperfect state present in both subspecies is Crinula caliciiformis (Fr.) ex Fr. Crinula Sacc. non Fries, Ditiola Schulzer non Fries, and Jugglerandia Lloyd are synonyms of Holwaya. Two species previously referred to the genus are excluded: H. salicis becomes Durandiella salicis (Müller & Ahmad) comb, nov.; H. pusilla belongs to the genus usually called Corynella Boud., but that generic name is an invalid later homonym. Claussenomyces Kirschst. is available to accommodate species previously placed in Corynella, and three new combinations are proposed, Claussenomyces atrovirens (Pers. ex pers.), C. prasinulus (Karst), and C. pusillus (Rehm); a key to the four accepted species of that genus is provided.
Conidium ontogeny in Coelomycetes. I. Some amerosporous species which possess annellides
Authors: Morgan-Jones G.
Published: September 2008

An illustrated account of conidium ontogeny is given for Macrophoma spp., Sarcophoma mirbellii (Fr.) Höhnel, Sirococcus gibberoideus (Cooke and Massee) Grove, Monostichella spp., Cryptocline betularum (Ell. and Mart.) Arx, and Leptomelanconium tremuloides (Ell. and Everh.) Arx.
Conidium ontogeny in Coelomycetes. III. Meristem thalloconidia
Authors: Morgan-Jones G.
Published: September 2008

Conidium ontogeny is described and illustrated for Vouauxiella lichenicola (Lindsay) Petrak and Sydow.
Developmental potentialities of leaf primordia of Osmunda cinnamomea. VI. The expression of P1
Authors: Haight Thomas H. , Kuehnert Charles Carroll
Published: September 2008

Data from culture experiments presented strongly suggest that the development of leaf primordia at the shoot apex may be divided into three phases in Osmunda cinnamomea. Phase I lasts from inception (Im) to some point in time during P1. Phase II probably begins somewhere between Im and I1, and may be retained as long as P9. Phase III is evident as early as P1 and continues through the entire primordial sequence to include Pn. In nature, or under experimental conditions where physiological continuity between the primordium and shoot apical meristem complex is maintained, O. cinnamomea primordial expression is phase III expression (leaf only). However, if the primordia produced at the shoot apex are removed from certain external biological influences (specifically the shoot apical meristem and certain older primordia) terminal expression of the primordia may be either phase I, phase II, or phase III depending upon the developmental phase of the primordia at the time of their isolation.
Protoventuria for venturiaceous Antennularia species
Authors: Barr Margaret E.
Published: September 2008

The genus Protoventuria Berl. & Sacc. is proposed to be reinstated for those species of the Venturiaceae previously assigned to Antennularia Reichenb. The necessary transfer of species from Antennularia to Protoventuria results in 13 new combinations.
Pigmentation in iris hybrids: occurrence of flavonoid pigments in six cultivars of Iris germanica
Authors: Ashtakala S. S. , Forward D. F.
Published: September 2008

Six cultivars of Iris germanica L. were found to contain similar pigments, whether the flowers were red, purple, blue, yellow, or white. All had one anthocyanin and a number of other flavonoids in common. All contained mangiferin. The anthocyanin, delphanin, was unstable on extraction and chromatography. Color differences could not be accounted for by differences in occurrence of any flavonoid substances. There is evidence for complexing of the anthocyanin pigment in vivo.
Crucibulum cyathiforme, a new bird’s nest fungus from Colombia
Authors: Brodie Harold J.
Published: September 2008

Crucibulum cyathiforme, described as a new species, is distinguished from C. laeve and C. parvulum by larger curved basidiospores, cyathiform shape, and pinkish color.
Interpretation of ectodesmata in relation to susceptibility to plant viruses
Authors: Litz R. E. , Kimmins W. C.
Published: September 2008

Ectodesmata were demonstrated in the outer walls of epidermal cells of French bean following treatment of leaf tissue with Gilson's solution.There was little change in the number of demonstrable ectodesmata with increasing age of the plant or as a result of increased suction tension of the culture solution. The number of ectodesmata was greater after darkening for 24 h but was not increased further with an additional period of darkening.These results are discussed in relation to studies on susceptibility to plant viruses and the structural evidence for ectodesmata. It is suggested that ectodesmata do not determine susceptibility to plant viruses and are not equivalent to the infectible site.
The cytology and kinetics of cabbage root hair penetration by Plasmodiophora brassicae
Authors: Aist James R. , Williams P. H.
Published: September 2008

After a primary zoospore of Plasmodiophora brassicae attaches to a cabbage root hair wall, the flagella coil, and the axonemes are soon retracted. During the next 2 h a dense-staining bullet-like Stachel is formed within a tubular cavity in the cyst, the Rohr. Possibly because of pressure created within an expanding cyst vacuole, the Rohr is quickly evaginated to form a bulbous adhesorium. The Stachel punctures the host wall and then, in a period of about 1 s, the parasite is injected into the root hair. The total time required for adhesorium formation and host penetration is about 1 min. Secondary zoospores were found to be capable of carrying out a similar penetration process. After penetration a callose-rich papilla is soon formed between the host wall and plasma membrane at the penetration site. Young amoebae in root hairs have no lipid bodies and are surrounded by seven-layered envelopes. Unidentified spherical inclusion bodies were seen sporadically in primary zoospores and cysts, and in uninucleate amoebae.
Callus, plantlet formation, and polyploidy from cultured anthers of Lotus and Nicotiana
Authors: Niizeki Minoru , Grant William F.
Published: September 2008

Anthers of Lotus corniculatus (a wild strain, cv. Empire and Viking) and L. caucasicus were cultured on agar-solidified media in an attempt to induce haploid plants. Calluses were readily obtained from the anthers, and chromosome number determinations on the callus tissues showed cells of different euploid and aneuploid chromosome numbers but no haploid cells. From these calluses, tetraploid and octoploid plants were regenerated. Except for some pollen grains which hypertrophied, the germ cells produced mature pollen but did not progress beyond this stage to initiate calluses. These results indicate that the calluses were derived from somatic tissues of the anthers rather than from the germ cells. Only a few cell divisions of the pollen grains occurred when they were cultured directly on agar-solidified medium. The induction of haploid plants by means of anther culture was successful for Nicotiana tabacum (cv. Wisconsin 38, Delhi 34, Hicks Broadleaf) but not for N. affinis. The autoradiographic study showed that uninucleate pollen differentiated into embryoids both before and after DNA synthesis for the first mitosis but not in any other developmental stage of the germ cells. The initiation of embryoids was concomitant with an increase in size of the pollen grains and vacuolization. Embryoid formation from pollen grains followed the same developmental process as in normal embryogenesis. Exogenous plant hormones, indole-3-acetic acid and kinetin, were responsible for embryoid formation, although they were not essential for initiation.
Congo red for instant distinction between poisonous Lepiota molybdites and edible L. brunnea
Authors: Weresub Luella K.
Published: September 2008

The spores of Lepiota species close to L. procera stain totally in ammoniacal congo red, whereas most mature spores of L. molybdites take up little or none of the orange color.
Meiosis in conifers: prolonged pachytene and diffuse diplotene stages
Authors: Owens John N. , Molder Marje
Published: September 2008

In four conifers studied, pollen mother cells began meiosis in the fall but remained at either a prolonged pachytene or diffuse diplotene stage for several months during winter; then meiosis resumed.
Selective medium for the isolation of wood-rotting basidiomycetes
Authors: Hunt R. S. , Cobb Jr. F. W.
Published: September 2008

Benomyl, dichloran, and phenol added to potato dextrose agar or water agar aided in the isolation of Fomes annosus and other wood-rotting basidiomycetes from stumps and roots. These additives suppressed the growth of many competitive organisms, especially Trichoderma spp. and blue stain fungi.
Lomasomes and vesicles in Poria monticola
Authors: Brushaber J. A. , Jenkins Jr. S. F.
Published: September 2008

A study of the vesicular and tubular bodies observed in cells of Poria monticola was done with particular regard to their form, origin, and membrane structure. The membranes of lomasomes and pinocytotic vesicles display the sometimes asymmetric, distinctly trilaminar structure characteristic of the plasma membrane. Lomasomes are abundant and vary in appearance depending upon the method of fixation used. Nonlamellar associations of vesicles and short tubules probably represent the true structure of lomasomes in this organism. These lomasomes originate from the plasma membrane and do not appear to be associated exclusively with wall formation.
Hybridization between Puccinia graminis tritici and Puccinia graminis secalis and its evolutionary implications
Authors: Green G. J.
Published: September 2008

The F2 progenies of four crosses, including one reciprocal, between Puccinia graminis tritici and P. graminis secalis included only cultures that were less virulent on wheat and rye than the parent that attacked one or other of these hosts. They closely resembled the F1 culture from which they were derived. A number of F2 cultures had low virulence on both wheat and rye. It is hypothesized that the hybrids resemble a more primitive form of Puccinia graminis and that evolution in the stem rusts of cereals is progressing from low virulence and wide host range to high virulence and reduced host range.
Measurement of activity of peroxidase isoenzymes in flax (Linum usitatissimum)
Authors: Hart M. A. , Tyson H. , Bloomberg R.
Published: September 2008

Peroxidase isoenzymes may be separated on acrylamide gels and then detected by supplying the substrate in an appropriate reaction system. One such system frequently used contains guaiacol as the hydrogen donor, although this compound has certain drawbacks. Ways of circumventing these drawbacks are suggested, so that quantitative estimates of the activity of individual peroxidase isoenzymes may be obtained.
The metabolism of L-proline by jack pine seedlings
Authors: Durzan D. J. , Ramaiah P. K.
Published: September 2008

The metabolism of L-proline was studied in 6-day-old jack pine seedlings, freshly excised from the nutritive female gametophyte. During the following 24 h, a sharp drop in free amino acids and protein was observed. Although levels of free proline were low, uniformly labeled 14C-L-proline and proline-3, 4-3H served as precursors for the dicarboxylic amino acids and their corresponding amides, glutamine and asparagine, which usually accumulate during germination. The origin of asparagine while unresolved did not involve β-cyanoalanine. Other products of proline metabolism included Δ1-pyrroline-5-carboxylic acid, glutamic acid, and γ-aminobutyric acid. With 14C-proline, radioactivity in alanine and serine resulted presumably from refixation of 14CO2 that was released by the decarboxylation of glutamic acid and other organic acids. The remaining products, e.g. pyrrolidone carboxylic acid, succinamic acid, and succinimide, were more closely related to the fate of glutamine than to proline.Radioactivity in proline and derived amino acids was recovered from soluble proteins separated on polyacrylamide gels. Five fractions revealed a similar diurnal turnover of specific activity. Three of these contained peroxidase isoenzyme activity. The recovery of tritium from peroxidase isoenzymes was related through the metabolism of proline to the intake and metabolism of water as well as to the appearance of enzyme activity in vascular tissues and emerging root and shoot apices.
Melanodothis caricis, n. gen., n. sp. and ‘Hyalodothis? caricis’
Authors: Arnold R. Horner
Published: September 2008

The structure and development of Melanodothis caricis n. gen., n. sp. (Dothideales, Dothideaceae), a fungus that parasitizes florets of Carex and Kobresia, are described and illustrated. Its relationship to ‘Hyalodothis? caricis’ Pat. & Har., herein considered a nomen dubium, is discussed. M. caricis is reported from the west coast of Canada, U.S.A. (Alaska), Japan, China, and New Guinea, on 14 species of Carex, one Carex hybrid, and one species of Kobresia. In Canada, the florets are infected in the spring at anthesis and the stromata reach their full size the same year, but asci and ascospores do not mature until the following spring. Mature asci were seen in stromata on four species of Carex, C. capillacea from New Guinea, and C. livida, C. pauciflora, and C. sitchensis from Canada, from field collections of mature stromata, and (or) from stromata brought to maturity under artificial conditions. The remaining records are of stromata with immature hymenium. Cultures from ascospores on potato dextrose agar are described.
Morphology and taxonomy of Entophlyctis confervae-glomeratae (Chytridiales) and related species
Authors: Barr D. J. S.
Published: September 2008

Culture studies of Entophlyctis confervae-glomeratae (Cienkowski) Sparrow showed that this chytrid was saprophytic on a wide range of plant matter including pine pollen, leaves, algae, and fungi. Morphological variation was so marked that many taxonomic criteria proved valueless and several synonyms are therefore suggested. A comparison with other species and genera is made. It is proposed that Entophlyctis include four species which are saprophytic on plant matter (E. confervae-glomeratae, E. texana Karling, E. pygmaea (Serbinow) Sparrow, and E. crenata Karling); a chitinophilic species (E. lobata Willoughby & Townley); and three species parasitic on algae (E. apiculata (Braun) Fischer, E. molesta Canter, and E. reticulospora Cook).
Entophlyctis confervae-glomeratae (Chytridiales): physiology
Authors: Barr D. J. S.
Published: September 2008

Two isolates of Entophlyctis confervae-glomeratae (Cienkowski) Sparrow grew at 10–25C and in the range pH 6–9. Both isolates used ammonium, nitrate, and nitrite nitrogen. They used glucose, fructose, trehalose, glycerol, sucrose, cellobiose, maltose, and starch but not lactose, xylose, ribose, sorbitol, raffinose, rhamnose, melibiose, N-acetyl-D-glucosamine, or cellulose.
Taxonomic studies in Avena abyssinica and A. vaviloviana, and some related species
Authors: Baum Bernard R.
Published: September 2008

This paper reports the use of micromorphologic attributes taken from the lodicules, epiblasts, and disarticulating scars for purposes of circumscription of the taxa associated with the names A. abyssinica and A. vaviloviana and their F1 hybrids, and also A. barbata. Furthermore it is shown that the epiblast can serve as a good marker to distinguish between the hexaploid A. byzantina and the tetraploid A. abyssinica, especially for those cases where previously only the chromosome number could have served this purpose. From the micromorphological findings, some cytological data, and plant distributional data, the author decided to regard A. abyssinica, A. barbata, and A. vaviloviana as separate species. The status of these species in previous classifications is compared with that proposed here. The many different classifications used in the past are attributed to the fact that no reliable diagnostic morphological markers were discovered by previous workers. A connection was discovered between A. occidentalis of the Canary Islands and the tetraploid abyssinian oats and a close relationship in this vicarious group is speculated.
Analyse des constituants de la fraction lipidique isolée du mycélium du Trichothecium roseum au cours des premiers stades de la croissance
Authors: Sancholle Michel , Montant Charles
Published: September 2008

Qualitative analysis of lipid extract fractions of mycelium of Trichothecium roseum from 2- to 4-day-old cultures, showed the presence of mono-, di-, and tri-glycerides, and phosphatidyl-choline (lecithines), phosphatidyl-ethanolamines and cardiolipides. Fatty acids are represented by myristic (C 14:0), palmitic (C 16:0), stearic (C 18:0), oleic (C 18:1), linoleic (C 18:2), and linolenic (C 18:3) acids.
Chromosome numbers and notes on some Central American grasses
Authors: Davidse Gerrit , Pohl Richard W.
Published: September 2008

Chromosome numbers are reported for 94 collections of grasses representing 61 species and 27 genera. Meiosis was analyzed and irregularities were noted. The probable reproductive method is discussed for some species with irregular meiosis. First chromosome counts are given for the following species: Luziola bahiensis, Aristida implexa, Briza rotundata, Gouinia guatemalensis, Bouteloua alamosana, Pentarrhapis scabra, Panicum cyanescens, P. incumbens, P. olivaceum, P. pantrichum, P. tenerum, Paspalum adoperiens, P. plenum, P. serpentinum, Thrasya campylostachya. Counts different from previous counts for the same taxon are reported for Axonopus capillaris, A. compressus, A. poiophyllus, Leptocoryphium lanatum, Paspalum centrale, P. pectinatum, Pennisetum setosum, and Hemarthria altissima.
De novo synthesis of fructo-oligosaccharides in leaf disks of certain Asteraceae
Authors: Chandorkar K. R. , Collins F. W.
Published: September 2008

Incubation of leaf disks of certain genera of Asteraceae on phosphate-buffered, 5% sugar solutions resulted in the de novo synthesis of a homologous series of inulin-type fructosans. Fructo-oligosaccharides of degree of polymerization 3 to 21 or 22 were present in dandelion, chicory, lettuce, hawkweed, and sow thistle leaf disks after 72 h, but not in dahlia or sunflower. Synthesis occurred with media containing either fructose, glucose, or sucrose, but not with mannose or galactose. Fructosan formation began after about 36 h and continued with the sequential synthesis of homologs of increasing chain length. After 72 h, the relationship between the amount of polymer synthesized and the chain length appeared to be logarithmically biphasic, consisting of two series of exponentially decreasing values. Incubation for 120 h however, resulted in a distribution more closely resembling that found naturally in fructosan storing tissues. 14C-tracer studies showed that both the endogenous and exogenous carbohydrate sources contribute to fructosan synthesis. Fructo-oligosaccharide formation was blocked by cycloheximide, puromycin, and actinomycin D but not chloramphenicol, indicating that cytoplasmic protein and nucleic acid synthesis was required. Analysis of fructosan formation during incubation suggests a close correlation between transfructosylation mechanisms observed in vitro and the de novo synthesis of fructosans in vivo.
Onset of the synthesis of RNA and protein in mature aleurone tissue of wild oats (Avena fatua)
Authors: Maherchandani N. , Naylor J. M.
Published: September 2008

Evidence is presented from autoradiographic experiments, indicating that the onset of protein synthesis in newly imbibed mature aleurone cells of Avena fatua L. is independent of the synthesis of "new" RNA. It is concluded that all fractions of RNA which are essential for protein synthesis survive for periods of several weeks, and probably for several years in caryopses held in dry storage. The results are consistent with previous reports of long-lived template-active RNA in mature, dry plant embryos.
Studies of the rooting of cuttings of Hydrangea macrophylla: enzyme changes
Authors: Molnar J. M. , LaCroix L. J.
Published: September 2008

Enzyme changes in root initials of Hydrangea macrophylla during adventitious root formation are described. Extensive changes in enzyme activity were demonstrated by histochemical staining and all enzymes investigated showed increased activity in the tissue responsible for root initiation.The earliest change observed was that of peroxidase in the phloem and xylem ray cells. This was followed by a change in the activity of cytochrome oxidase and succinic dehydrogenase. Alpha-amylase was localized by the substrate film method. The highest amylase activity was demonstrated in the epidermal tissues and vascular bundles. As the root primordia developed, enzyme activity shifted from the vascular bundles to the periphery of the bundles. A positive correlation was found between the starch content and root number of cuttings.
Localization of oleic acid biosynthesis enzymes in the proplastids of developing castor endosperm
Authors: Zilkey B. F. , Canvin D. T.
Published: September 2008

The particulate fatty acid synthesizing system from the developing castor bean endosperm was separated using sucrose density gradients. The particulate fatty acid synthesizing enzymes were associated with a particle of peak density 1.21 g∙(cm3)−1. Based on the presence of triosephosphate isomerase and the appearance of the particles in electron micrographs the major constituent of this fraction was identified as proplastids. It appears that in this tissue the proplastid contains the complete enzyme complement for oleic acid synthesis from acetyl or malonyl-CoA.
Fossil wood of Taxaceae from the McMurray formation (Lower Cretaceous) of Alberta, Canada
Authors: Roy S. K.
Published: September 2008

The paper describes a single species of fossil wood, Taxaceoxylon mcmurrayensis sp. nov., belonging to Taxaceae. The wood shows remarkable resemblance to the wood of the extant genera Taxus and Nothotaxus. This is the first record of this family from the McMurray formation (Lower Cretaceous).
Ecological life cycle and physiological ecology of seed germination of Arabidopsis thaliana
Authors: Baskin Jerry M. , Baskin Carol C.
Published: September 2008

Field observations were made on the ecological life cycle of the winter annual Arabidopsis thaliana (L.) Heyn. from a population in central Tennessee, and a detailed laboratory study was conducted on the physiological responses of the seeds to temperature in light (14-h photoperiod) and constant darkness. At maturity and dispersal (late April and early May), seeds germinated to high percentages only at low temperatures (5–10 °C) in light. With storage from May to September and October (1) the maximum temperature for germination in light increased from 15 to 30 °C and in darkness from 10 to 20 °C and (2) the optimum temperature for germination in light increased from 5 to 15–20 °C and in darkness from 5 to 5–10 °C. During the spring–summer period seeds were dormant at temperatures simulating those in the natural habitat. In September and October, seeds in light germinated to high percentages at simulated September and October temperatures but did not germinate in darkness at the September temperatures and germinated poorly at October temperatures. Regulation of germination so that it occurs in early autumn allows A. thaliana to persist in a summer-arid habitat.
The effect of an audible and low ultrasound frequency on the growth of synchronized cultures of Scenedesmus obtusiusculus
Authors: Weinberger Pearl , Das G.
Published: September 2008

The effects of sonication of synchronized cultures of Scenedesmus obtusiusculus Chod. were examined. Two frequencies, 4 kHz and 19 kHz were applied during various phases of the diurnal mitotic cycles. As a result of 4-kHz sonication the average cell division decreased. During exposure to 19-kHz sonication the average rate of cell division initially increased slightly, but mitotic division was subsequently inhibited when the cells were exposed to prolonged sonication. A "relaxation" period of two generations was required before the cells regained their normal rate of productivity (cell number increase). The cells were more sensitive to sonic shock during the first quarter of their 24-h life cycle and apparently insensitive during the last quarter. No chromosomal effect was observed. It is suggested that sonication alters specifically timed events that occur at the earlier stages of the life cycle.
Chromosome races in Rumex arcticus (Polygonaceae)
Authors: Mulligan Gerald A. , Frankton Clarence
Published: September 2008

Rumex arcticus Trautv., a species found on the mainland of northwestern North America and in northeastern U.S.S.R., contains tetraploid (2n = 40), dodecaploid (2n = 120), and perhaps 2n = 160 and 2n = 200 chromosome races. Most North American plants are tetraploid and are larger in size and have more compound and contiguous inflorescences than typical R. arcticus. Typical plants of R. arcticus occur in the arctic U.S.S.R., St. Lawrence Island in the Bering Sea, and at the tip of the Seward Peninsula of Alaska, and they all have 120 or more somatic chromosomes. High polyploid plants of R. arcticus that resemble North American tetraploids in appearance apparently occur on the Kamchatka Peninsula. These have been called R. kamtshadalus Komarov or R. arcticus var. kamtshadalus (Kom.) Rech. f. by some authors.