bluuebunny/crossref_metadata_2025 huggingface dataset:
A silicified semiaquatic dicotyledon from the Eocene Allenby Formation of British Columbia
Authors: Robison Coleman R. , Person Christopher P.
Published: September 2008

A silicified dicotyledon rhizome is described from the Eocene Allenby Formation of the Princeton Coal Basin, British Columbia. The primary and secondary vascular tissues of the rhizome form a narrow cylinder around a broad, parenchymatous pith. The rhizome's salient feature is a wide cortex in which there are numerous air cavities. In most specimens the cortex is surrounded by a single layer of epidermal cells but in some there is evidence of periderm initiation. Small lateral branches are borne on the main axis, and both the main and lateral axes bear broad, clasping leaf bases and adventitious roots. The affinities of this rhizome are presently unknown, but its anatomical structure is indicative of a semiaquatic plant.
Heart rot of black spruce in Ontario. II. The mycoflora in defective and normal wood of living trees
Authors: Basham J. T.
Published: September 2008

The fungi most frequently associated with heart rot in black spruce stems were the Basidiomycetes Fomes pini (Fr.) Karst., Scytinostroma galactina (Fr.) Donk, Polyporus tomentosus Fr., Peniophora septentrionalis Laurila, and Coniophora puteana (Schum. ex Fr.) Karst. Factors related to the occurrence of these and other Basidiomycetes are assessed. An Ascomycete, Ascocoryne sarcoides (Jacq. ex Gray) Groves and Wilson, was frequently isolated from both clear and defective wood in living black spruce (Picea mariana (Mill.) B.S.P.) stems older than 75 years of age. In laboratory tests this fungus invaded but did not appreciably alter black spruce heartwood, and provided some protection against subsequent decay by F. pini. Evidence is presented that the widespread occurrence of A. sarcoides in mature black spruce stems partly explains the relatively low incidence of defect in this species. The potential use of A. sarcoides as an agent for the biological control of decay in black spruce and other conifers is discussed.
A new species of Cyathus from the Philippines
Authors: Brodie Harold J.
Published: September 2008

Cyathus gracilis sp. nov. from the Philippine Islands is characterized by its slender brown fruit bodies in which the basal portion is long and narrow. External hairs are aggregated into sharp conical tufts. The peridiole tunica is absent or nearly so and the cortex is distinctly two-layered.
Zoospore development and fine structures in Phlyctochytrium arcticum (Chytridiales)
Authors: Chong James , Barr D. J. S.
Published: September 2008

The fine structures of Phlyctochytrium arcticum zoospores, from early differentiation in the sporangium until they encyst and germinate, are described. Cytoplasm cleavage and flagellum formation have been studied. A complex rhizoplast–kinetosome structure is present. The Stüben body associating with a nucleus in a differentiating zoospore apparently divides into a number of similar bodies which are observed in the subsequent stages. Mitochondria, which are scattered about in the cytoplasm of maturing zoospores, are clustered at the posterior end of the motile zoospore, surrounding the kinetosome and the rhizoplast. On encystment, the flagellum is retracted, the rhizoplast disappears, the mitochondria again become scattered in the cytoplasm, and a wall is rapidly laid down. The morphology of the P. arcticum zoospore is compared with other chytridiaceous zoospore types.
Influence of Criconemoides quadricornis on pecan feeder root necrosis caused by Pythium irregulare and Fusarium solani at different temperatures
Authors: Hsu Diensie , Hendrix Jr. Floyd F.
Published: September 2008

Fusarium solani significantly reduced root weight of pecan seedlings at 21–27°. Pythium irregulare reduced root weight at 21 °C but not at 27 °C. Criconemoides quadricornis did not reduce root weights of pecans at these temperatures even though its population tripled in 60 days at the higher temperature. There was a synergistic reaction between C. quadricornis and either F. solani at 21 °C or P. irregulare at 27 °C. These are the temperatures least favorable for pathogenesis caused by the fungi. There were additive effects between these organisms at the temperature most favorable for pathogenesis caused by the fungi.
Observations on the zoospores of Pseudendoclonium basiliense and Trichosarcina polymorpha (Chlorophyceae)
Authors: Mattox Karl R. , Stewart Kenneth D.
Published: September 2008

The zoospores of Pseudendoclonium basiliense and Trichosarcina polymorpha possess body scales similar to scales in Chara, Nitella, Coleochaete, and certain green monads that are often placed in a separate class, the Prasinophyceae. Otherwise, the zoospores are of the "ulotrichalean" type; that is, the basal bodies of the four flagella are two L-shaped pairs arranged in mirror-image relation. It is concluded that "prasinophytes" are not separable from the Chlorophyceae. Scales are indistinct and of brief occurrence on the zoospores of T. polymorpha, but in P. basiliense scales occur on the outer surface of the cell walls of germlings and on the walls of aplanospores. Evolution of more complex motile cells of plants is briefly discussed. It is suggested that Pseudendoclonium and certain other chaetophoralean or ulotrichalean algae might be better included in the same order with Ulva, Enteromorpha, Percursaria, and Trichosarcina, but a firm decision awaits studies of mitosis and cytokinesis.
A tubule–membrane complex characteristic of paraphyses for two species of Sclerotinia
Authors: Tu J. C. , Colotelo N.
Published: September 2008

A cylindrical tubule–membrane complex was observed only in thin sections of paraphyses of apothecia of Sclerotinia borealis. In paraphyses of S. sclerotiorum an extensive but less compact tubule–membrane complex was observed. Ribosomes were much more abundant in paraphyses than in other tissues.
Pestalozzina uniseptata
Authors: Raj T. R. Nag
Published: September 2008

Pestalozzina uniseptata Grove, so far considered a coelomycete, is shown to be an ascomycete of thegenus Oxydothis Penz. & Sacc.
Vegetative remains of Azolla schopfii Dijkstra from Genesee, Alberta
Authors: Sweet A. R. , Chandrasekharam A.
Published: September 2008

An extension of the description of Azolla schopfii Dijkstra to encompass the vegetative parts was made possible by the discovery of vegetative material of Azolla with attached reproductive structures at the Genesee fossil plant locality of Paleocene age in central Alberta.Detailed descriptions of the reproductive structures of A. schopfii are given. A close relationship is suggested between A. schopfii and species within subgenus Rhizosporma Meyen, particularly A. nilotica Decainse, based on similarities in the morphology of the vegetative parts and their associated reproductive structures.
An enlarged concept of Trichobolus (Thelebolaceae, Pezizales) based on a new eight-spored species
Authors: Krug J. C.
Published: September 2008

A new eight-spored species, Trichobolus octosporus, is described and illustrated. The generic concept has been enlarged to include this taxon. A revised generic description and key are provided. The species is discussed in relation to previously known organisms within the genus.
The use of fluorochromes for the identification of β (1 → 3) glucans
Authors: Faulkner G. , Kimmins W. C. , Brown R. G.
Published: September 2008

The fluorescent staining properties of aniline blue and primuline with isolated preparations of variously linked glucans was investigated. Neither fluorochrome was specific for β (1→3) linked glucose units.
Stomata in Equisetum
Authors: Dayanandan P. , Kaufman P. B.
Published: September 2008

Light and scanning electron microscopic studies and guard cell isolation techniques have confirmed the well-known ridges of the Equisetum stomatal apparatus as belonging to the subsidiary cells. Hitherto unknown features of the subsidiary cells such as the presence of a concentrated H2SO4-resistant region on the ridges and an interlocking mechanism for the closure of the aperture of the subsidiaries are described. These are presented as further evidence for the differences between the two subgenera of Equisetum. Boiling in dilute NaOH is shown to be a simple but effective means for the isolation of the guard cells in Equisetum as well as in several other plants with sunken stomata. Silicification of the outer layer of the epidermis makes cuticular isolation a difficult process by usual methods (treatments with enzymes or cellulose hydrolyzing reagents). Treatment with concentrated sulfuric acid followed by hydrofluoric acid results in the isolation of the cuticular membranes in Equisetum spp. and in similarly silicified grasses. Involvement of potassium ions in stomatal movements is indicated for two ferns and suggested for two species of Equisetum.
Effects of ozone on 14CO2 fixation patterns in pine
Authors: Wilkinson Thomas G. , Barnes Robert L.
Published: September 2008

Seedlings of white pine (Pinus strobus L.) and detached shoots of white and loblolly (P. taeda L.) pines were exposed to various concentrations of ozone either before or during photosynthetic fixation of 14CO2. The major changes in distribution of 14C as a result of ozone treatment were (1) a reduction of relative activity in soluble sugars; (2) an increase in activity in sugar phosphates; and (3) an increase in activity in free amino acids, especially alanine. Significant differences in 14C fixation patterns were observed at ozone concentrations as low as 10 pphm (parts per hundred million), and during 14CO2 fixation times as short as 10 min. However, other combinations of treatment levels and times did not always result in statistically significant effects.
The growth of selected mycorrhizal fungi in response to induced water stress
Authors: Mexal John , Reid C. P. P.
Published: September 2008

Three ectomycorrhizal fungi, Cenococcwn graniforme, Suillus luteus, and Thelephora terrestris were grown in artificial nutrient media. Water potential of the media was varied by the use of the osmoticum polyethylene glycol (PEG) 4000 and measured by thermocouple psychrometry. Cenococcum graniforme was very tolerant of low water potentials and exhibited maximum growth at a potential of −15 bars. Maximum growth of S. luteus and T. terrestris occurred at −5 bars. The water potential of solutions containing PEG 4000 appears to consist of both an osmotic and matric component, making PEG 4000 ideally suited for simulation of soil moisture stress. It was neither metabolized nor readily absorbed by C. graniforme as inorganic salts or sugars might be.
The postglacial diatom history of Sunfish Lake, southwestern Ontario
Authors: Sreenivasa M. R. , Duthie H. C.
Published: September 2008

An investigation was made of the diatom stratigraphy in a sediment core from Sunfish Lake, a small (8.3 ha), deep (20 m), meromictic lake in southwestern Ontario. About 340 diatom species and varieties distributed among 37 genera were identified from the sediments; however, only 16 taxa had more than 2% representation in any sample. On the whole, the number of individuals and diversity of the samples increase over the postglacial period. Diatoms first appear in pollen zone A and consist mainly of the littoral forms Cymbella diluviana, Fragilaria lapponica, and F. construens var. venter. It is suggested that these taxa are typical of early postglacial lacustrine sediments in northeastern North America. Cyclotella bodanica first appears in zone B and is dominant in most samples throughout the core. It is euplanktonic and typical of subalpine, circumneutral, oligotrophic lakes. In C2, when the climate was possibly warmer and drier than present, there is evidence for a lower lake level: C. bodanica is temporarily replaced in importance in the sediments by C. kuetzingiana and the proportion of littoral and epiphytic diatoms increases. Cyclotella bodanica regains its former importance in C3 sediments with the possible return to a cooler, wetter climate. About 850 years before present (B.P.) the lake evidently became eutrophic. Cyclotella bodanica declines and there is an increase in the proportion of several species typical of a higher trophic level, e.g., Stephanodiscus hantzschii, Cyclotella glomerata, and several Synedra spp. The cause is unknown. The lake probably became meromictic about 140 B.P. at a time when the forest was cleared and agriculture began in the watershed.
Some mycoparasites of western bark fungi
Authors: Funk A.
Published: September 2008

Some mycoparasitic fungi are reported for the first time on various microfungi associated with bark diseases of forest trees in British Columbia, Canada, viz., Engelhardtiella alba gen. et sp. nov., Cylindrocarpon roseum sp. nov., and Phymatotrichum fungicola Zeller.
The Trichocomaceae (Ascomycetes): synonyms in recent publications
Authors: Malloch David , Cain R. F.
Published: September 2008

The genera Gymnoeurotium, Harpezomyces, and Sporophormis, all described recently by Malloch and Cain, are shown to be later synonyms of Chaetosartorya, Edyuillia, and Warcupiella, respectively, described 2 months earlier by Subramanian. Syncleistostroma Subr. is rejected as a nomen confusum because of discrepancies between the generic description and the designated type species, leaving Petromyces Malloch & Cain the correct generic name for the species involved.
Root and root hair growth of oats: replaceability of calcium
Authors: Tanaka Yasuomi , Woods F. W.
Published: September 2008

Oat (Avena sativa L.) seedlings were grown in nutrient solutions deficient in either calcium, magnesium, or potassium as well as in single-salt solutions containing each of these elements. Strontium was studied using a nutrient solution in which calcium was replaced by strontium.The absence of magnesium or potassium did not affect root elongation in media containing calcium. Solutions containing only calcium nitrate supported some root growth but growth was negligible in all other single-salt solutions. When calcium was replaced by strontium, primary root growth and cell elongation were significantly reduced. However, there were no other readily detectable morphological changes resembling symptoms of calcium deficiency.Root hair elongation was not affected by the exclusion of either magnesium or potassium from nutrient solutions, but calcium deficiency (sodium substitution) resulted in less elongation and in deformation. Of all the single-salt solutions, only calcium nitrate supported normal root hair growth. Although root hairs were not deformed, formation and elongation were considerably reduced in strontium-substituted solutions. Strontium, in mineral nutrient media, may prevent toxic effects of other ions but does not completely replace calcium for root and root hair growth of oats.
Life cycle of the marsh grass, Scolochloa festucacea
Authors: Smith Alan L.
Published: September 2008

This paper describes the life cycle of Scolochloa festucacea, a dominant species in potholes subjected to regular burning or mowing throughout the Drift Prairie and Missouri Coteau of the Northern Great Plains. Vernal growth is initiated at extremely low temperatures; some plants grow in water at the freezing point. Flowers develop in June if the pothole is inundated in the spring. Mature caryopses drop in July, but do not germinate until the next year. Tillers and new rhizomes are produced in August, followed by senescence in late September – early October.
Conidium ontogeny in hyphomycetes. The meristem arthrospores of Wallemia sebi
Authors: Hashmi M. H. , Morgan-Jones G.
Published: September 2008

Conidium ontogeny in Wallemia sebi (Fr.) v. Arx is analyzed and illustrated by time-lapse photomicrography. The nuclear configurations occurring during conidiogenesis are described and subsequent nuclear distribution reported. The conidia are considered to be meristem arthrospores of a unique type.
Mitosis and nuclear degeneration: simultaneous events during secondary sporangia formation in Phytophthora palmivora
Authors: Hemmes Don E. , Hohl Hans R.
Published: September 2008

Somatic nuclear division is described for sporangia of Phytophthora palmivora. The division is intranuclear and involves centrioles and an eccentrically located spindle. The nucleolus persists throughout division. While these events take place, other nuclei within the same sporangium become surrounded by membranous material and degenerate by an autophagous process. The possible significance of these events for this stage of the life cycle is discussed.
Photosynthesis and growth of Douglas-fir seedlings when grown in different environments
Authors: Sorensen Frank C. , Ferrell W.K.
Published: September 2008

Douglas-fir seedlings from western Montana and western Oregon seed sources were grown in a cool (18 °C day – 4 °C night) or warm (36 °C day – 21 °C night) growth chamber. Photosynthetic and respiratory rates were measured at 20°, 27.5°, and 35 °C at cotyledon stage (15 to 18 days old), 55 days old, and 100 days old. Needle, stem, and root dry weights were also determined. Photosynthetic rates declined with age, were higher for Oregon than for Montana seedlings, particularly at lower measurement temperatures, were higher for high-temperature-grown than for low-temperature-grown plants, and were lowest at the highest measurement temperature. Each of these factors was modified by the others in its effect on the photosynthetic rates. Respiration rates declined with age, were slightly higher for Montana than for Oregon seedlings, were much higher for the cold-temperature-grown than for the warm-temperature-grown seedlings, and were highest at the highest measurement temperature. When plants from the two growth environments were interchanged, the photosynthetic rates (measured at 27.5 °C only) of the seedlings changed to those of the new environment within 10 days. Comparison of seedlings grown at high and low temperatures showed the latter to have lower photosynthetic rates but higher growth rates, probably as a result of the higher proportion of leaf tissue produced by the low-temperature-grown plants.
Intracellular location of potato virus S in leaf tissue of Chenopodium quinoa
Authors: Hlruki C. , Shukla P.
Published: September 2008

The presence of potato virus S (PVS) in the local lesions of Chenopodium quinoa was shown by bioassay, a serological test, and electron microscopy of negatively stained preparations of the infected tissues. Amorphous aggregates of particles believed to be PVS were found with the electron microscope in ultra-thin sections of both necrotic and nearby chlorotic cells of lesions sampled 8 days after inoculation of C. quinoa. The virus masses were confined to the cytoplasm and found in close proximity to the nucleus, chloroplasts, and tonoplasts. No other cellular inclusions were found in these cells.
Marine fungi isolated from a Kraft pulp mill outfall area
Authors: Churchand L. M. , McClaren M.
Published: September 2008

Wood- and leaf-inhabiting marine fungi were collected from two depths near the effluent outlets of a Kraft pulp mill in Howe Sound, British Columbia. Other sites which were not directly affected by pulp mill effluents were also sampled. All groups of fungi grew poorly on baits which rested on the bottom at the mill. At a depth of 30 cm, Phycomycetes were isolated as frequently from the mill as from control sites. Of the Fungi Imperfecti, Monodictys pelagica (Johnson) Jones was isolated more frequently from the mill than from control sites; Zalerion maritimum (Linder) Anastasiou was isolated less frequently from the mill than from control sites. Phialophora fastigiata (Lagerb. & Melin) Conant was isolated exclusively from the pulp mill station. Ascomycetes were rarely found on panels submerged at the pulp mill.Hydrographic measurements showed that water temperature at the mill sample site was not affected by the effluent. Salinity and pH were generally lower at the pulp mill than at the control site, and may have been partially responsible for the observed distributional differences.
A scanning electron microscope study of Cucurbita maxima seed coat structure
Authors: Lott John N. A.
Published: September 2008

The examination of the seed coat of Cucurbita maxima with the scanning electron microscope provided information about the three-dimensional structure of the seed coat cells. The lumpy appearance of the spongy parenchyma cells indicated that localized wall growth must have occurred. Also of particular interest were the reticulate secondary wall thickenings in the hypodermal and spongy parenchyma regions of the seed coat. The developing squash seed coat may prove to be a good model system in which to study the cell wall deposition process.
The genus Atriplex (Chenopodiaceae) in Canada and Alaska. III. Three hexaploid annuals: A. subspicata, A. gmelinii, and A. alaskensis
Authors: Bassett I. J. , Crompton C. W.
Published: September 2008

Descriptions, illustrations, and distribution data are given for three closely related species of Atriplex native to North America. Most populations of Atriplex subspicata (Nutt.) Rydberg are hexaploid, with a chromosome count of 2n = 54. Two populations were found with counts of 2n = 36. Atriplex gmelinii C. A. Meyer and A. alaskensis S. Watson are hexaploids. Atriplex subspicata has been confused by North American botanists with A. patula L. and A. hastata L. but these introduced species are respectively tetraploid and diploid.
Adaptive tolerance of Fusarium solani to benzimidazole derivatives in vitro
Authors: Richardson Lloyd T.
Published: September 2008

The growth response of Fusarium solani to benomyl or thiabendazole in the medium was found to differ from that of many other Fusarium species tested. In contrast to the steep, linear dosage–response curve typical for this genus, the curve for F. solani invariably reaches a maximum at about 1.0 μg/ml and is horizontal from there on. During a single exposure to either benomyl or thiabendazole, F. solani develops tolerance to both toxicants, but its subsequent growth on untreated medium is retarded. Cross-tolerance to other benzimidazoles is also induced. Such adapted strains generally maintain their slow growth habit and tolerance indefinitely through successive transfers to either untreated or treated medium. Occasionally a colony growing slowly on untreated medium will produce a sector which grows normally but proves to be sensitive when transferred to treated medium. Conversely, colonies of this sensitive strain, while growing extremely slowly on treated medium, more frequently produce a sector like the resistant strain. From observation of the response of a large number of single-spore isolates it is concluded that in the presence of a benzimidazole a high proportion of the wild population can mutate to the slow-growing, resistant type. Such mutants occasionally revert to the wild type.
Investigations of the marine algae of Nova Scotia. XI. Additional species new or rare to Nova Scotia
Authors: Edelstein T. , Bird C. , McLachlan J.
Published: September 2008

Twenty-one additional species new or rare to Nova Scotia are reported. Of these, 12 belong to the Rhodophyceae, 6 to the Phaeophyceae, 1 to the Chlorophyceae, and 2 to the Xanthophyceae. Acrochaetium porphyrae and Scytosiphon dotyi, two species previously known only from the west coast of North America, are recorded for the first time from the Atlantic coast of that continent. Porphyrodiscus simulons and Entonema polycladum, known from Europe, are also recorded for the first time in North America.
Ultrastructure and conidiogenesis in Conioscypha (Hyphomycetes)
Authors: Shearer C. A. , Motta J. J.
Published: September 2008

Conioscypha lignicola Höhnel and C. varia Shearer were studied with the electron microscope. Conidiogenesis appears to be intermediate between annellidic and phialidic. Single conidia are produced endogenously by a percurrently proliferating conidiogenous cell. The wall of the conidium initial and its basal septum do not participate in the structure of the conidium.
Chromosome numbers, pollen fertility, and pollen size in Haworthia species and hybrids
Authors: Majumdar S. K. , Riley H. P.
Published: September 2008

Sporophytic chromosome numbers were determined for 216 species, varieties, or hybrids of the genus Haworthia. There were 152 diploids (2n = 14), 10 triploids, 38 tetraploids, 7 pentaploids, 7 hexaploids, and 2 aneuploids. Among the species studied, most of the diploids were highly fertile. The tetraploids were somewhat less so, the triploids were generally less than 50% fertile, and the pentaploids and hexaploids were generally intermediate between the diploids and the triploids. The few diploid interspecific hybrids were less fertile than the diploid species. Each additional set of chromosomes increased the pollen size, and this increment was found to be significant up to the tetraploid level. Statistical analyses of comparisons between pollen size means of the hexaploids and pentaploids, and of the pentaploids and tetraploids were not significant. Pollen sterility is interesting in connection with the problem of speciation in the Aloineae, which is discussed.
The effect of light and other factors on spore germination in Botrychium dissectum
Authors: Whittier Dean P.
Published: September 2008

Light-inhibited spore germination in Botrychium dissectum forma obliquum occurred in axenic culture on a nutrient medium containing 0.25% sucrose. The spores had to be cultured in darkness for 3–4 weeks before any germination would take place. Longer periods in the dark produced greater percentages of germination. Sucrose was unnecessary for germination, but it promoted gametophytic growth once germination had occurred.
Isolation, culture, and uses of plant protoplasts
Authors: Gamborg Oluf L. , Miller R. A.
Published: September 2008

Techniques are now available for isolating plant protoplasts in any quantity from leaves or from cultured cells by enzymatic removal of the cell walls. The culture conditions for regenerating dividing cells and complete plants has been established for a few species. Intact viruses enter plant protoplasts and multiply. Spontaneous fusion occurs in protoplasts of the same species. Mitosis frequently takes place synchronously in the nuclei of the multinucleated protoplasts. Induced fusion of widely different species such as wheat and soybean has been demonstrated. Hybrid plants of two tobacco species have been produced by cell fusion. Transformation has been achieved by feeding isolated DNA to plants. Isolated DNA supplied to protoplasts is absorbed. The progress in plant cell and protoplast research demonstrates the feasibility of transferring genetic information and makes hybrid plant production by somatic cell hybridization a realistic objective.
The use of cultured tissue in studying developmental problems
Authors: Halperin Walter
Published: September 2008

Selected aspects of studies dealing with xylogenesis, organ and embryo formation, and vegetative propagation in vitro are reviewed.
Control of growth and cell division in plant cell suspension cultures
Authors: King P. J. , Mansfield K. J. , Street H. E.
Published: September 2008

In batch suspension cultures variation occurs in the growth and metabolism of the cells both in space and with time. Viable cell populations of sycamore (Acer pseudoplatanus L.), showing greatly reduced aggregation and more uniform morphology, can be obtained by incorporating enzymes into the culture medium. Such techniques combined with single cell cloning will take us closer to uniformity within the culture. The problem set by the continuous change in the metabolic activities of the cells with time (during the progress of the growth cycle of batch cultures) has been overcome by the use of low-density synchronous cultures and by the establishment of steady states of growth in chemostat cultures. Experimental work with sycamore cell suspensions is described showing (1) the achievement of prolonged cell division synchrony in 4-liter suspension cultures and (2) the conformity of the growth kinetics of cells in chemostat culture to the mathematical model developed by Monod (1950, Ann. Inst. Pasteur (Paris), 79: 390–410) for microorganisms.
Nitrate and ammonium as nitrogen nutrients for plant cell cultures
Authors: Veliky I. A. , Rose Dyson
Published: September 2008

A chemically defined 71V medium was designed in accordance with data from studies of NH4+ and NO3− requirements for biomass production of carrot cell suspension culture (CA-68 line). Under the described conditions, the optimum ratio of NH4+:NO3− was 20:80, and the optimum total nitrogen level was about 500 mg N per liter of medium. The observed changes in pH of the different inorganic media during the growth of the culture might be an important factor influencing the nitrogen metabolism of the cells.
Cyclopentanecarboxylic acid, a B-ring analog with activity antagonistic to gibberellin
Authors: Marcus Rita R. , Goldthwaite Jonathan
Published: September 2008

Cyclopentanecarboxylic acid (CPCA) acts as a weak gibberellin (GA) antagonist for three diverse responses to GA: d5 dwarf maize growth, Rumex leaf disc senescence, and amylase production in barley half-seeds. The inhibitory effect is completely overcome by simultaneous application of saturating doses of GA3 or GA7 in dwarf maize. CPCA did not affect zeatin-inhibited senescence in the Rumex system or auxin-promoted growth of oat coleoptile sections. The results are compared with other recent work with GA antagonists.
The effect of variable-frequency sounds on plant growth
Authors: Weinberger Pearl , Graefe U.
Published: September 2008

Four tunes and two random noise selections were used to determine whether variable sound frequencies may affect the growth and development of cucumber, corn, and oats. The selections were subjected to a power spectral density analysis. Some growth changes were observed and an indication given that a growth - audio action spectrum may be a widespread general phenomenon.
Glycolate metabolism in young and old tobacco leaves, and effects of α-hydroxy-2-pyridinemethanesulfonic acid
Authors: Salin Marvin L. , Homann Peter H.
Published: September 2008

Young tobacco leaves photorespire less than older leaves. This difference is reflected by lower activities of photorespiratory enzymes in young leaves, and by an apparent inability to synthesize glycolate, the substrate of photorespiration.It is shown in this paper that young tobacco leaves differ from old ones in the following, additional respects: (1) extracts have a much lower ability to decarboxylate glycine; (2) the transient burst of CO2 after lowering of the light intensity is nearly absent; (3) photosynthesis is much less inhibited when leaves are floated on solutions of the inhibitor of glycolate oxidase α-hydroxy-2-pyridinemethanesulfonic acid (HPMS); (4) the CO2 compensation concentration is higher; and (5) the mesophyll cells are much more densely packed.It is concluded that the small photorespiratory gas exchange of young leaves is due to deficiencies in enzymes of glycolate metabolism and perhaps to a slow synthesis of glycolate. The latter may be explained by a relatively high internal CO2 concentration resulting from large physical resistances to gas exchange in the tissue. However, the rate of glycolate formation possibly is underestimated because of a low permeability of young leaf tissue to HPMS.Other results provide evidence that HPMS alters the biochemical pattern of CO2 photoassimilation in old tobacco leaves under certain conditions. Hence, this poison ought to be used with caution in studies on photorespiration and glycolate metabolism.
A technique for evaluating functional root biomass in grassland ecosystems
Authors: Singh J. S. , Coleman D. C.
Published: September 2008

A technique for evaluating functional root biomass in grassland ecosystems with the aid of carbon-14 is described. Plots were labeled by releasing 14CO2 inside polyethylene tents. Root samples were mounted on a sheet of paper, exposed to X-ray film, and separated into functional and non-functional categories through autoradiography. The functional component in unmounted samples was estimated with the help of regression, relating the percentage of functional biomass with radioactivity determined through liquid scintillation counting.
The genus Trechispora (Basidiomycetes, Corticiaceae)
Authors: Liberta Anthony E.
Published: September 2008

Twenty-one species of Trechispora are described and illustrated, and a key to the species is included. Six species are transferred to Trechispora: Corticium albo-ochraceum Bres., Cristella bispora Warcup & Talbot, Cristella gillesii Maas G., Polyporus molluscus (Pers.) ex Fr., Poria regularis Murr., and Corticium subsphaerosporum Litsch. One species is transferred to Cristinia: Corticium filium Bres. Fifteen names are reduced to synonymy and seven taxa formerly residing in either Cristella or Trechispora are excluded.
Effects of temperature on the morphology and photosynthetic activity of newly matured leaves of alfalfa
Authors: Ku S. B. , Hunt L. A.
Published: September 2008

Effects of temperature on (1) physical characteristics of newly matured leaves throughout regrowth, and (2) net carbon dioxide exchange–irradiance response curves throughout regrowth and throughout the day are described for two alfalfa (Medicago saliva L.) genotypes (AT171 and CC120) grown at 20/15C and 30/25C day/night temperatures and 53 nE cm−2 s−1 irradiance (400–700 nm).Area per leaf increased linearly with increasing leaf number up to the fourth or fifth leaf, and thereafter remained constant. Both specific leaf weight and leaf density were constant for the first four leaves, and increased sharply thereafter, particularly at day/night temperatures of 20/15C. Percentage of leaf water content did not change throughout regrowth at 30/25C, but decreased after leaf 4 at 20/15C. Intercellular space volume fluctuated with leaf number. Leaf area was larger, specific leaf weight, and leaf density were greater, intercellular space volume was higher, and percentage of leaf water content was lower, with plants grown at 20/15C than at 30/25C.The net carbon dioxide exchange rate at 116 nE cm−2 s−1 increased with leaves produced progressively until a peak was reached at leaf 4 or 5 and then decreased. At any given leaf position, net carbon dioxide exchange rate at 116 nE cm−2 s−1 was greater at 20/15C than at 30/25C for AT171, but was the same at both temperatures for CC120. In contrast, net carbon dioxide exchange rate at 76 nE cm−2 s−1 was greater at 20/15C than 30/25C for both genotypes. Net carbon dioxide exchange rates measured in the morning were always lower than those measured in the afternoon regardless of irradiance, genotype, and growth temperature.
CO2 fixation in a mutant of corn, white-3, which lacks carotenoids
Authors: Richmond B. J. , Bidwell R. G. S.
Published: September 2008

The white-3 (w3) mutant of corn which lacks carotenoids is capable of a low rate of light-stimulated CO2 fixation in dim red light. Bright light inhibits CO2 fixation. The products of CO2 fixation indicate that w3 lacks a normal Calvin cycle, but fixes carbon by carboxylation reactions that lead to the production of several organic acids. These reactions appear not to be related to the C4 photosynthetic cycle. In addition, the w3 mutant does not make amino acids from photosynthetic carbon.
De novo synthesis of fructooligosaccharides in leaf disks of certain Asteraceae. II. Certain physiological and biochemical changes accompanying fructooligosaccharide formation
Authors: Collins F. W. , Chandorkar K. R.
Published: September 2008

De novo synthesis of fructosans in leaf disks of certain Asteraceae incubated on phosphate-buffered 5% sucrose medium was accompanied by increases in fresh and dry weight and a considerable enhancement in the rate of respiration. Radiorespirometry using 14C-sucrose showed that the respiratory pool was kept at the expense of both exogenous and endogenous substrates. During the initial 24 h of incubation, about 80% or more of the total respiratory carbon was derived from the exogenously supplied sugar. This proportion gradually decreased during the last 48 h to a final value of about 50%. Of the total sugar taken up by the leaf disks, less than 20% was utilized in respiration while more than four-fifths was available for further metabolism including fructosan formation. The respiratory quotient values remained relatively unchanged from 0.8 to 0.9 throughout most of the incubation period and suggested that endogenous substrate other than carbohydrate was drawn into respiratory metabolism.
Color, brightness, and other floral characteristics attracting insects to the blossoms of some Canadian weeds
Authors: Mulligan Gerald A. , Kevan Peter G.
Published: September 2008

This paper is concerned with those floral characteristics that appear most important in the long-distance attraction of pollinating insects to the blossoms of weeds: color and brightness of flowers, size of the flower target, and the odor of the flowers. Weed flowers that are occasionally or frequently visited by insects tend to have a higher reflectance in ultraviolet and in blue than do flowers that are rarely visited. The flowers most visited, generally have flower targets over 20 mm in diameter and (or) flowers that are odoriferous. None of these characteristics appears to be of prime importance in determining which kinds of insects visit the flowers of weeds. Many weeds have flowers or flower heads with the outer portion reflecting ultraviolet and (or) blue wavelengths and a central portion absorbing these wavelengths. These flower characteristics, and information on life durations, breeding systems, and pollen vectors are used to evaluate the different strategies that enable weeds to rapidly build up large populations in constantly disturbed habitats.
Effective mechanical inoculation of plant viruses in the absence of water
Authors: Ragetli H. W. J. , Weintraub M. , Elder M.
Published: September 2008

Tests with powdered, dry inocula prepared from virus-diseased leaves by grinding the latter in liquid nitrogen and freeze-drying the finely divided tissue, resulted in high infection rates of a variety of plant species. Ten widely differing viruses and 12 test species belonging to seven plant families were investigated. It was shown that early virus–host interactions leading to virus establishment in the test plants in the course of mechanical inoculation generally do not require the mediation of water. With some test species dry inoculation was even more effective than sap inoculation, irrespective of the presence or absence of (proteinaceous) virus inhibitors in the inoculum. In the presence of inhibitors the effectiveness of dry inoculation seems to depend on a spatial separation of viral and inhibitory agents, because inhibition of virus establishment per se was also found not to require water. The effectiveness of dry inoculation appears to depend further on host characteristics, probably of an ultrastructural nature, as well as on properties of the viruses. Isometric virions and those approaching isometry might be more effective in dry inoculation than elongated ones. Electron microscopic examination of the dry leaf powders revealed the virions to be present mostly as monomers of rather uniform length.
The bacterial and fungal flora of the bark, wood, and pith of alder, black cottonwood, maple, and willow
Authors: Sivak Bela , Person C. O.
Published: September 2008

The occurrence and distribution of symbiotic cauloplane organisms on dormant cuttings of 1- to 2-year-old stems of alder, black cottonwood, maple, and willow were determined from tissue samples removed to 2% malt extract and nutrient broth agars, and from scanning electron micrographs of the bark surfaces. Fungal and bacterial symbionts were found to be confined to the bark surfaces, where their occurrence was related to the surface topography. Inner bark, wood, and pith were virtually aseptic.
Effect of moisture stress on red maple seedlings from different seed sources
Authors: Townsend Alden M. , Roberts Bruce R.
Published: September 2008

Red maple (Acer rubrum L.) seedlings grown from half-sib seed collected from wet and dry sites were subjected to three levels of plant water stress. Transpiration on a per seedling and per unit leaf weight basis was greatest in seedlings from a swamplike site, at both high and low water potentials. Seedlings from the two wet sites came to temporary and permanent wilt sooner than seedlings from dry sites. However, at all levels of water stress, growth rates were greater for the seedlings from the wet sites than for those from the dry sites. At permanent wilt, the stem and leaf moisture content and the water potential values were highest in the seedlings from the swamplike site. At temporary wilt, the leaf water potential was lowest in seedlings from dry sites. Transpiration of seedlings from a swamplike site was double that of those from another wet site at the same leaf water potential.
Cylindrocarpon gillii, a new combination for Septogloeum gillii on dwarf mistletoe
Authors: Muir John A.
Published: September 2008

The fungus previously known as Septogloeum gillii D. E. Ellis which causes an anthracnose disease of the shoots of dwarf mistletoes (Arceuthobium spp.) in western North America is assigned, on the basis of its conidiophore morphology and spore formation, to the genus Cylindrocarpon. Accordingly, the new combination Cylindrocarpon gillii (D. E. Ellis) J. A. Muir is proposed.
Influence of phenylboric acid on germinating fern spores
Authors: Caruso John L.
Published: September 2008

Fern spores exposed to phenylboric acid at 100 mg/liter produced cells which divided slowly and attained a greater ratio of length over width as compared to control specimens. This pattern in cell growth may explain the morphogenetic effects of phenylboric acid on higher plants.
Identical and non-identical seedling twins in Pinus radiata
Authors: Burdon R. D. , Zabkiewicz J. A.
Published: September 2008

Thirteen sets of twin seedlings emerging from single seeds of Pinus radiata were raised. Using morphology in 2 cases and oleoresin analysis in the remaining 11, six sets were accepted as genetically identical, one probably identical, two probably non-identical, and four definitely non-identical. Therefore, twins apparently result from both cleavage and archegonial polyembryony.
A bioassay for systemic fungicides using axenic cultures of the carnation rust fungus, Uromyces dianthi
Authors: Jones D. R.
Published: September 2008

The inhibitory action of three systemic fungicides (Benlate, Hoe 6053, and Milstem) on the growth of axenic cultures of the carnation rust fungus, Uromyces dianthi, was assessed. The rust- and smut-specific fungicide (Hoe 6053) was found to inhibit growth when present in the agar medium in very low concentrations, while moderate concentrations of the wide range fungicide (Benlate), and high concentrations of the powdery mildew-specific fungicide (Milstem) were needed for inhibition. The results indicated the possible use of U. dianthi in future in vitro fungicide screening programs and mode-of-action studies.
An ultrastructural and cytochemical study of microbodies in the genus Nitella (Characeae)
Authors: Silverberg B. A. , Sawa T.
Published: September 2008

Electron microscopy of the cells of the characean alga Nitella flexilis revealed the presence of numerous spherical inclusions which morphologically resemble plant microbodies. The structures have a dense granular matrix and are bounded by a single membrane. Many of the microbodies contain very electron-dense nucleoids that were shown to be alpha-amylase sensitive. In cells of the young apex, microbodies are the most abundant cellular organelle and are intimately associated with dilated cisternae of the endoplasmic reticulum and Golgi complexes, and with large osmiophilic lipid bodies. Although the microbody population appears reduced in mature branchlet cells and internode cells of the main axis, they exhibit a characteristic and frequent association with the chloroplasts. Turnover of microbodies involves some autolytic degradation of the body matrix until complete digestion presumably occurs. Developmental changes of microbodies were monitored with the cytochemical localization of lysosomal aryl sulfatase and acid phosphatase activities. The current study is of interest since catalase, an enzyme marker of microbodies in a variety of tissues, could not be detected using both cytochemical and enzyme assay methods. The functional role of microbodies in Nitella cells is explored in relation to presently available information.
Fine structure of conidiogenesis in the holoblastic, sympodial Tritirachium roseum
Authors: Hammill Terrence M.
Published: September 2008

Electron microscopy of conidiogenesis in Tritirachium roseum was done on material fixed in glutaraldehyde followed by OsO4. The walls of conidiogenous cells, though pigmented, lacked well-defined differential electron-transmission layers. Conidial initials developed without the appearance of a rupture in the conidiogenous cell wall, i.e., development was holoblastic. Each successively produced conidiogenous locus developed below and to one side of the previously formed conidium, and the fertile region of the conidiogenous cell elongated in a geniculate pattern. After each conidial initial reached full size, it was delimited by a centripetally developing septum, which increased in thickness, became double, and split during conidial secession. The distal half of a split septum formed the conidial base; the proximal half remained as part of the conidiogenous cell wall. Upon conidial secession, basal frills on conidia, and secession scars on conidiogenous cells were especially conspicuous.
Mineral composition of grassland species of the Eastern Great Basin in relation to stand productivity
Authors: Harner Richard F. , Harper K. T.
Published: September 2008

Floral and mineral composition of the vegetation on 12 foothill grassland sites in the Eastern Great Basin has been studied. Aboveground production differed widely among the sites (871–2388 kg/ha per year). Both floristic and mineral composition of the vegetation changed conspicuously across the productivity gradient. As production increased, total nutrient uptake by the aboveground vegetation also increased. This increase was only partially due to greater production; average nutrient content per gram of tissue (all species pooled) also increased along the productivity gradient.Roughly 82% of the variation in total annual production was accounted for using an index of site mesicness. Mesic sites were dominated by forbs, while grasses or shrubs were dominant on xeric sites. The mesic sites were far more productive than xeric sites. The greater nutrient element content of plant tissue from the most productive sites in this study was related more to a shift in dominance from grasses and shrubs to forbs, than to nutrient status of the soil.
Numerical taxonomy of the genus Rhizopus
Authors: Dabinett P. E. , Wellman Angela M.
Published: September 2008

Numerical techniques were used to investigate published data from studies on the genus Rhizopus. These techniques have produced a classification broadly in agreement with that based on a more classical approach, but a regrouping of the Oryzae section of the genus, which has been the most difficult to classify in the past, is proposed. This work was based on a study of 149 attributes of each of 34 individuals. An investigation of the characters revealed that with the possible exception of temperature-response characters no particular sets of characters can be said to contribute significantly to the classification. An investigation of seven of the previous classifications using objective methods shows that three classifications are in general agreement with the one tentatively proposed here.