bluuebunny/crossref_metadata_2025 huggingface dataset:
Anatomically preserved plants from the Middle Eocene (Allenby Formation) of British Columbia
Authors: Basinger James F. , Rothwell Gar W.
Published: September 2008

Well preserved, permineralized plant material from the Middle Eocene, Allenby Formation of British Columbia provides the basis for this description of an extensive Tertiary flora. The flora comprises a diverse assemblage of abundant plant remains in a chert matrix which outcrops south of Princeton, B.C., Canada. Preliminary examination of this material reveals numerous fertile and vegetative organs of angiosperms, conifers, ferns, bryophytes, and fungi, most of which represent presently unknown taxa. Initial studies indicate that we are dealing with the most diverse Eocene permineralization flora ever discovered. Superb anatomical preservation, including developmental stages of various organs, characterize many of the taxa and promise to significantly increase our knowledge of early Tertiary plants.
Patterns of conidial release by Helminthosporium turcicum on sweet corn under controlled environmental conditions
Authors: Palmerley R. A. , Benedict W. G.
Published: September 2008

Patterns of conidial release by Helminthosporium turcicum Pass. (Trichometasphaeria turcica Luttrell) on sweet corn (Zea mays L.) were studied over 24-h periods under controlled environmental conditions. During the night (dark for 10 h, 100% relative humidity (RH)), relatively few conidia were trapped below diseased seedlings and there were no obvious peaks of spore release. During the day (light for 14 h, 70% RH), however, many conidia were caught (usually four to six times as many as during the night), and there were either one (with 10-week-old seedlings) or two (with 6-week-old seedlings) peaks of spore release. Conidia trapped during the day period were considered to have been released as a result of drying of the leaves. Those trapped during the night were considered to have been washed passively from leaf surfaces. No evidence was obtained to link conidial release with increasing RH.
Sporulation and peroxidase in Bipolaris maydis: effects of xylose and thiamine
Authors: Garraway M. O. , Evans R. C.
Published: September 2008

Sporulation of the fungus Bipolaris maydis increased and peroxidase (EC 1.11.1.7) activity decreased when xylose was added as a supplement to a basal glucose – mineral salts – agar medium containing either L-asparagine or NaNO3. With L-asparagine, thiamine–HCl (1.0 mg/ℓ) caused a significant decrease in sporulation and an increase in peroxidase activity. The magnitude of the decrease induced by thiamine–HCl in sporulation and increase in residue peroxidase activity appeared greater on a non-supplemented medium than on one supplemented with xylose. With NaNO3, the magnitude of the decrease in sporulation induced by 0.1 mg/ℓ thiamine–HCl appeared comparable whether or not the medium was supplemented with xylose, but the magnitude of the increase in residue peroxidase activity was greater without than with xylose. Quantitative determination of intracellular phenols as possible substrates for peroxidase revealed that there was no change in total phenol concentration regardless of the xylose and thiamine–HCl content of the media. The apparent inverse relationship between sporulation and peroxidase activity in B. maydis provides clues to the specific regulatory mechanisms involved in sporulation.
Apical dominance in the rhizome of Agropyron repens. The relation of amino acid composition to bud activity
Authors: Nigam S. N. , McIntyre Gordon I.
Published: September 2008

The polarity of bud growth in isolated, decapitated rhizomes of Agropyron repens L. Beauv. was correlated with the amino acid content of the buds and rhizome nodes and with the external N supply. In rhizomes from low-N plants grown under controlled conditions, the levels of asparagine and glutamine decreased markedly from the apical to the basal nodes and this gradient was closely correlated with a basipetal reduction in the growth of the rhizome buds. All other amino acids included in the analysis also showed a basipetal gradient of decreasing concentration but they were present in much lower concentrations than the amides and their correlation with bud growth was less precise. In high-N rhizomes collected in the field, the amino acid gradient was considerably reduced and the relatively uniform distribution of amide-N along the rhizome was correlated with a similar uniformity in growth of the rhizome buds.Increasing the N supply to intact plants released the lateral buds from inhibition. A significant growth response occurred within 48 h and was associated with a 30% increase in the amide-N content of the rhizome. Sprouting of buds on isolated nodes resulted, within 48 h, in a 42% reduction in the amide concentration in the node, as compared with nodes from which the bud had been removed and in which considerable amide accumulation occurred. Significant reductions in proline, serine, and alanine were also recorded.It was concluded that, under N-deficient, low water stress conditions, the inhibition and polarity of bud growth is mainly determined by the N supply, whereas, the relatively high concentrations of amino acids found in the fully inhibited buds of field rhizomes suggested, in accordance with previous results, that water rather than N was more likely to be the limiting factor under field conditions.
Cytochemical studies on the gland in the primary haustoriumof Phthirusa (Loranthaceae)
Authors: Toth Ronald , Kuijt Job
Published: September 2008

Acid phosphatase (EC 3.1.3.2) activity was not detected in the gland of the haustorium of Phthirusa. The absence of this enzyme supports the hypothesis that the gland does not function in accumulating digestive enzymes to aid in host penetration.
Ascocarp ultrastructure of Herpomyces sp. (Laboulbeniales) and its phylogenetic implications
Authors: Hill Terry W.
Published: September 2008

The asci of Herpomyces sp. (Laboulbeniales) compose a parenchymatous tissue produced by progressive cleavage of three or four meristematic ascogenous cells attached in the base of the ascocarp. Ascospores are delimited by membranes derived from an ascus vesicle, and the spore wall forms between paired prospore membranes. Dilated cisternae and epiplasmic membranes are associated with wall formation. While ascospores are developing, asci are displaced apically, their passage apparently lubricated by a matrix secreted by the peridial cells.The presence of an ascomycetous spindle pole body, septal pore with Woronin bodies, ascus vesicle, and dilated Golgi-like cisternae indicates a close relationship between Herpomyces sp. and the filamentous Ascomycetes while providing no support for theories maintaining a close relationship between Laboulbeniales and the red algae.
Morphological acclimation to light intensity in Douglas-fir seedlings
Authors: Drew Allan P. , Ferrell William K.
Published: September 2008

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were grown outdoors under 9, 44, and 100% light intensity and were sampled periodically over their first growing season for stem, leaf, and root dry weights, and the data were analyzed allometrically. In addition, seedlings were assessed for number of needles per stem length, ratio leaf surface area: leaf dry weight, and maximum seedling dry weight. The experiment was repeated during a 2nd, warmer, year.Maximum growth occurred under partial shade and moderate temperatures. In the 1st year, seedlings allocated progressively more dry matter to shoot than to root growth as light intensity decreased. In the 2nd year, root growth was favored at the expense of shoot growth. In both years, shoot structural alterations were such as to favor enhanced photosynthesis under low light. Acclimative changes are explained in terms of an interaction between light, temperature, and seedling size.A second experiment showed that seedlings grown under low light set a terminal bud sooner in the fall and broke bud sooner the next spring than seedlings preconditioned to high light. They also suffered more spring frost damage and showed greater incidence of lammas growth in the 2nd year. No effect of 1st-year preconditioning on timing of budbreak was evident in the 3rd year.
Expression of resistance in bean pods to an incompatible isolate of Pseudomonas syringae
Authors: Webster D. M. , Sequeira L.
Published: September 2008

Isolates of Pseudomonas syringae from hairy vetch were either virulent (compatible) or avirulent (incompatible) to bean. When bean pods were injected at high inoculum levels (5 × 107 cells/ml), both compatible and incompatible isolates multiplied rapidly and caused water-soaking of injected tissues; populations of both isolates were similar at the end of log phase. Lesions caused by the incompatible isolate turned brown by 3 days after inoculation and did not expand; those caused by the compatible isolate remained water-soaked and expanded into the adjoining, noninoculated tissues. At low inoculum levels (5 × 104 cells/ml), the compatible isolate exhibited the same pattern of multiplication and lesion development as at the high inoculum level. The incompatible isolate, on the other hand, caused necrotic flecking within the injected area by 24 h, and these small lesions remained limited. Appearance of the necrotic flecks was correlated with a progressive decline in bacterial populations; after5 days, the population of incompatible bacteria was about a hundredfold lower than that of compatible ones. Populations of incompatible bacteria within and between the necrotic flecks declined rapidly, indicating the potential accumulation of inhibitors of bacterial growth as a result of an inducible resistance mechanism.The phytoalexin phaseollin reached 280 μg/g fresh weight by 3 days after inoculation of bean pods with incompatible bacteria. However, this compound was not involved in resistance. Neither compatible nor incompatible isolates of the bacterium were significantly inhibited when grown in a medium saturated with phaseollin. When other antibiotic substances in plant extracts were sought, substantial amounts of inhibitory compounds were detected only in the ethanolic extract (fraction soluble in ethyl acetate) of pods previously inoculated with an incompatible isolate of P. syringae. Only low levels of inhibition were obtained from identical extracts of uninfected pods or from pods inoculated with a compatible isolate of P. syringae. Bacterial growth was completely prevented in a bean infusion medium containing 1 g fresh weight equivalent of pod tissue challenged with the incompatible isolate. The active compound(s) was nonfluorescent, had a UV absorption maximum at 286 nm, and gave a positive reaction with reagents for phenolic compounds.
Structural studies of Chondrus crispus: the effect of extraction of carrageenan
Authors: McCandless E. L. , Okada W. T. , Lott J. N. A. , Vollmer C. M. , Gordon-Mills E. M.
Published: September 2008

Birefringence, energy-dispersive x-ray analysis (EDX), and ultrastructural studies were performed on control and on extracted carposporic and tetrasporic Chondrus crispus Stack. thalli.EDX analysis of untreated carposporic and tetrasporic plants revealed the presence of sulphur primarily in the intercellular matrix and cell walls. The sulphur levels detected were greater in tetrasporic than in carposporic plants. EDX analysis of tetrasporic and carposporic plants after extraction with hot aqueous bicarbonate, which should remove most of the sulphated polysaccharide carrageenan, showed little sulphur in walls and intercellular matrices.The microfibrils visible with transmission electron microscopy in cell walls of both generations of C. crispus appeared to run parallel to the cell surface, i.e. circumferentially. Some areas of the intercellular matrix were entirely granular, while others contained microfibrils. After extraction, microfibrils in cell walls and intercellular matrix were disorganized but were still present, perhaps in reduced amounts.The birefringence which characterized the walls of untreated cells was greatly reduced by 2 h extraction, and matrix birefringence was entirely removed. Cortical cell walls could still be identified and stained metachromatically with toluidine blue, but they were no longer birefringent. Further extraction (5 h) removed residual birefringence, but rhizoid cell walls were still metachromatic, as were the remnants of small cells believed to be cortical in origin.
Studies of the pathway of HCN formation from glycine in a psychrophilic basidiomycete
Authors: Ward E. W. B. , Starratt A. N. , Robinson J. R.
Published: September 2008

Eleven [14C]-labeled amino acids were tested for their ability to serve as precursors of HCN in cultures of a psychrophilic basidiomycete. Only glycine and, to a much lesser degree, L-serine and L-aspartic acid were effective. By using [2-14C, 15N]glycine, it was demonstrated that the C–N bond remains intact during the conversion to HCN. No evidence was obtained for the participation of N-hydroxyglycine or glyoxylic acid oxime as intermediates in the pathway of HCN formation.
Outcrossing rates in natural populations of Plectritis brachystemon (Valerianaceae)
Authors: Ganders Fred R. , Carey Ken , Griffiths A. J. F.
Published: September 2008

Plectritis brachystemon is polymorphic for plants with winged or wingless fruits. The polymorphism is controlled by a single locus with the allele for winged fruits exhibiting complete dominance. Using this locus as a genetic marker, progeny tests of natural populations gave estimated outcrossing rates of 0 to 3.33%. Heterozygotes were infrequent in the populations sampled. Populations fixed for one allele or the other at the winged-fruit locus are common in P. brachystemon but are rare in the related outcrossing species P. congesta.
A taxonomic study of the genus Crosbya (= Bellia; Musci)
Authors: Vitt Dale H.
Published: September 2008

The name Bellia Broth. (1907, Hookeriaceae) is a later homonym of Bellia Bubani (1899, Umbelliferae) and the name Crosbya is proposed as a replacement for the moss name. A taxonomic and numerical treatment of this genus shows that Crosbya nervosa (Hook. f. & Tayl.) Vitt and Crosbya straminea (Mitt. ex Beck.) Vitt are separate species. A polygraphic analysis indicates that the two species are morphologically distinct. Crosbya nervosa is endemic to the northern portion of the Auckland Islands and Campbell Island, whereas C. straminea is endemic to New Zealand.
Classification of Myriogenospora in the Clavicipitaceae
Authors: Luttrell E. S. , Bacon Charles W.
Published: September 2008

Myriogenospora atramentosa (Berk & Curt.) Diehl has been found on species of Paspalum, Andropogon, Eragrostis, and Panicum in surveys of pastures with histories of toxicity problems in cattle. The fungus produces a systemic infection in which growth on the host is entirely superficial. Infection of each leaf and inflorescence occurs from mycelium in the bud. In the upper part of the leaf one side of the blade remains unexpanded and is bound into a tight roll by a mass of fungus plectenchyma that it encloses. Branches of the inflorescence are enmeshed in a fungus matrix and remain enclosed within the flag leaf sheath. Superficial, linear, black stromata form down the middle of the leaf alongside the leaf roll and in the juncture between margins of the flag leaf sheath. The stromata produce fusoid conidia in a fleeting early stage. Immersed perithecia develop in a longitudinal row in the stroma. The cluster of aparaphysate asci on a basal cushion, lateral paraphyses, and indistinct peridia of the perithecia are characteristic of the Clavicipitaceae. The numerous fusoid spores in the swollen asci are part-spores derived from fragmentation of eight filiform, septate ascospores. The refractive cap at the apex of the ascus is a modification of the typical clavicipitaceous structure. Myriogenospora is placed in the tribe Balansiae of the Clavicipitaceae.
Effects of auxins and chemically related non-auxins on photosynthesis and chloroplast ultrastructure in Alaria esculenta (Laminariales)
Authors: Buggeln R. G. , Bal A. K.
Published: September 2008

Blade meristems of Alaria esculenta (L.) Grev. (Laminariales, Phaeophyta) were treated with growth-inhibiting concentrations (10−3 M) of auxins and chemically related non-auxins, e.g., 2,4- and 3,5-dichlorophenoxyacetic acids, respectively. Photosynthesis was inhibited with increasing effectiveness by both auxins and non-auxins in the following classes: naphthaleneacetic < naphthoxyacetic <phenoxyacetic acids. Inhibition was reversed by transferring sections to fresh seawater from naphthaleneacetic and naphthoxyacetic acids. Chloroplast swelling, observed in electron micrographs of lateral portions of Alaria blade meristems, was positively correlated with the degree of inhibition of photosynthesis. The ratio of 14C incorporation into mannitol and amino acid fractions of alcohol-soluble organic matter was also modified by the inhibitors, especially phenoxyacetic acids.A 50% increase in photosynthetic rate of the blade meristem occurs within 24 h of its excision from the Alaria frond.
Valeur morphologique de 1'involucre du cyathe chez le genre Euphorbia: étude expérimentale
Authors: Coquen C.
Published: September 2008

In three species of Euphorbia, we have obtained teratological specimens induced by different processes; their analysis allows us an interpretation of the involucre of the cyathium. Involucral bracts have their origin in leaves and the glands are double structures of stipular origin.
Changes during development in the compartmentalization patterns of extractable gibberellin-like substances in 'single' and 'double' genotypes of Nigella damascena
Authors: Raman K. , Greyson R. I.
Published: September 2008

The 'double'-flowered and 'single'-flowered genotypes of Nigella damascena possess different levels and compartmentalization profiles of the methanol-extractable acidic-ethyl-acetate-soluble (AES) and highly water-soluble (HWS) gibberellins. 'Single' tissues at all stages possess less total gibberellin than the 'double' tissues. At flowering, 'double' tissue contains 20 to 30 times (500 μg/kg fresh weight) the levels of seedling tissue and 10 to 20 times the levels of 'single' flower tissue. Seedlings of both forms possess AES and HWS gibberellins at about equal levels. However, at flowering, virtually all methanol-extractable gibberellins of the 'double' are located in the AES extract and the 'single' flower bud possesses essentially all HWS gibberellins.
The conversion of [2-14C]mevalonic acid into triterpenes and tetraterpenes by cell-free extracts of a Neurospora crassa albino mutant
Authors: Bobowski G. S. , Barker W. G. , Subden R. E.
Published: September 2008

Evidence for the conversion of [2-14C]mevalonic acid into triterpene and some tetraterpene components of Neurospora crassa in a cell-free system is presented. Radioactivity in the non-saponifiable neutral lipid extracts of the incubated cell-free extract was partitioned into three fractions by column chromatography. Purification of the radioactive component of one of these fractions by column chromatography and analysis by ultraviolet-absorption spectroscopy, thin-layer chromatography, and gas chromatography showed the radioactivity to be present primarily in squalene. Preliminary analysis of the remaining two fractions indicated the incorporation of mevalonate into phytoene and sterol intermediates. The conversion of mevalonate into squalene exhibited an absolute requirement for ATP and Mn2+ and was enhanced in the presence of NADP or NADPH.
Trisomic analysis of genes for resistance to scald and net blotch in several barley cultivars
Authors: Bockelman H. E. , Sharp E. L. , Eslick R. F.
Published: September 2008

Barley cultivars Kitchin (C.I. 1296) and Jet (C.I. 967), resistant to scald (incited by Rhynchosporium secalis (Oud.) Davis), and cultivars Tifang (C.I. 14373), C.I. 9819, and C.I. 7584, resistant to net blotch (incited by Pyrenophora teres Drechs.), were crossed to the primary trisomics in the cultivar Betzes. F2 segregation ratios were studied to determine chromosomal location of the resistance genes. Kitchin was found to contain a single scald-resistance gene, Rrs9, on chromosome 4. Jet contained scald-resistance genes rrs1 and rrs6 on chromosomes 3 and 4, respectively. Tifang contained a single gene, Rpt1a, for net-blotch-resistance on chromosome 3. C.I. 7584 contained a single net-blotch-resistance gene, Rpt3d, on chromosome 2. C.I. 9819 contained net-blotch-resistance genes Rpt1b and Rpt2c on chromosome 3 and 5. Some uses of this information are discussed.
Morphology and development of aerial roots of Selaginella martensii grown in moist containers
Authors: Webster Terry R. , Jagels Richard
Published: September 2008

Aerial roots of Selaginella martensii Spring, grown in moist containers, produce root caps and root hairs after 3 to 4 weeks. Tips of capless, hairless aerial roots are green because of starch-containing chloroplasts in the cortex. As roots develop pigmentation is gradually lost. By the time that caps and hairs are formed the apices are colorless and contain a zone of amyloplasts in the cortical region. The external morphology of roots grown in moist chambers closely resembles that of roots grown in soil but ultrastructural plastid changes are quite distinct. The cortical cell plastids of differentiated roots grown in moist chambers resemble chromoplasts (but lack color), while cortical cell plastids of soil-grown roots develop prolamellar bodies typical of etiolated tissues. The results support an earlier interpretation that the organ in question is a root throughout development.
L'induction chez Ceratocystis de fructifications de types Graphium et Leptographium par des acides gras insaturés
Authors: Dalpé Yolande , Neumann Peterjürgen
Published: September 2008

The unsaturated fatty acids oleic, linoleic, and linolenic induce the formation of the imperfect state of fructification of the Graphium type (coremia) with Ceratocystis ulmi and C. piceae and the Leptographium type with C. penicillata. Intraspecific difference between several strains of C. ulmi show that linoleic acid is the best inducer with an optimal concentration from 0.05 to 0.20 g/ml of methanol between the 10th and 25th day of culture. Linoleic and linolenic acid extend the capacity of sporulation of C. penicillata, conserving the strains capability of differentiation of Leptographium structures when ordinarily only the natural substrate can reinduce it. Ceratocystis dryocoetidis cultivated in the same conditions remains insensible to the lipid treatments.
Physiological aspects of the ecology of Dicranum fuscescens in the subarctic. II. Seasonal patterns of organic nutrient content
Authors: Hicklenton Peter R. , Oechel Walter C.
Published: September 2008

Individual plants of Dicranum fuscescens were collected from two field sites (a highland semitundra and a lowland lichen woodland) near Schefferville, Quebec (latitude 55° N), for 4½ months during 1974. Collections were made at 2-week intervals from June until the 2nd week in October. Samples were separated into green and brown shoot components and oven-dried. Subsequently analyses were carried out to determine concentrations of total carbohydrates (sugar and starch) and lipids in the respective tissues. Total carbohydrates were found to increase in the green tissues towards the end of the season reaching a maximum of between 10 and 10.5% ash-free tissue dry weight in October. Lipid concentrations showed a maximum of between 3.6 and 4.0% ash-free dry weight during July and subsequently declined, in the same tissues. Seasonal trends of nutrient concentration in the brown portions of the shoot were not marked.An investigation of biomass distribution in complete plants of D. fuscescens revealed that brown shoots accounted for more than half of the total. Mean lengths of these parts of the shoot were about twice those of the upper stem.
An apomictic mutant for sticky chromosomes in the fern Ceratopteris
Authors: Hickok Leslie G.
Published: September 2008

A meiotic mutant has been derived from a triploid hybrid of the fern genus Ceratopteris. The mutant behavior involves chromosome stickiness that is regularly observed during both meiotic divisions. Chromosome stickiness is also infrequently observed during mitotic division. In addition, the first meiotic division frequently fails and results in the formation of a restitution nucleus. A single second meiotic division follows restitution and results in the production of a dyad of unreduced spores. Viable unreduced spores germinate to produce gametophytes containing the sporophytic number of chromosomes. Spermatozoids produced by the gametophytes are non-functional. However, sporophytes regularly develop apogamously from the gametophytes. Because meiotic reduction and syngamy are absent, the mutants are, reproductively, obligate apomicts.
Estimating dry-matter accumulation in soybean
Authors: Heilman J. L. , Kanemasu E. T. , Paulsen G. M.
Published: September 2008

Equations to estimate gross photosynthesis, respiration, and dry-matter accumulation for soybean from daily estimates of intercepted, photosynthetically active radiation (PAR) were developed from field measurements. We found that gross photosynthesis was a function of intercepted PAR and that 24-h dark respiration was a function of gross photosynthesis. In addition, we developed equations relating intercepted PAR to leaf area index (LAI) and solar radiation. We assumed that gross photosynthesis was reduced when soil-water depletion was greater than 65%. The growth model predicted accumulated dry matter for soybean in 1974, 1975, and 1976 to within 2.7 mg cm−2 of observed values.
Ultrastructural development of merosporangia in the mycoparasite Syncephalis sphaerica (Mucorales)
Authors: Baker K. L. , Hooper G. R. , Beneke E. S.
Published: September 2008

Transmission and scanning electron microscopy were used to study the development of Syncephalis sphaerica (Piptocephalidaceae, Mucorales) merosporangia. Merosporangia were initiated as simple evaginations of the ampulla wall. Three spores were cleaved out of each merosporangial protoplast by invaginations of the merosporangial plasmalemma. An abscission zone was formed in each cleavage zone. A fibrillar spore wall was laid down between the spore plasmalemma and the inner lining layer of the merosporangial wall. Portions of the outer merosporangial wall remained attached to the spore at the time of detachment. During late cleavage, a wall was laid down on the surface of the ampulla at the base of each merosporangium forming a scar. Mature spores remained associated with the ampulla as a spore drop.
Growth rates of the lichen Lobaria oregana as determined from sequential photographs
Authors: Rhoades Frederick M.
Published: September 2008

The foliose lichen Lobaria oregana (Tuck.) Müll. Arg. is an important nitrogen-fixing component of the canopy epiphyte community in old-growth Douglas fir forests of the Pacific Northwest. This paper presents a non-destructive method for estimating the growth rate (grams per year) for L. oregana thalli of different weights.Photographs were made over a 2-year period of six in situ thalli. From a relationship of the photographic thallus area and weight of these and 31 other thalli, the dry weight of each of the six thalli is estimated through time. A growth rate is computed for each thallus and a relationship between growth rate and initial thallus weight is determined. Growth rate (grams per year) = exp (−0.8581 + 0.8444 (loge initial weight (grams))). The maximum radial growth rate of lobes of L. oregana determined from the photographs (9.4 mm/year) is comparable with rates for similar species.
A developmental study of the stamens in a male-sterile tobacco hybrid
Authors: Hicks G. S. , Bell J. , Sand S. A.
Published: September 2008

The ontogeny of the feminized stamens in a male-sterile tobacco hybrid has been studied. Plant material 1A was derived from an initial cross between Nicotiana debneyi as female and N. tabacum cv. Kupchunos as male. All 1A flowers exhibit stigmatoid anthers at anthesis and are sterile. This teratism is cytoplasmically inherited. In a developmental series of 1A floral buds, it was found that 1A stamen primordia diverge relatively early from the normal stamen shape and appear as spatulate organ rudiments lacking differentiation into anther and filament. In 1A buds after carpel fusion and as the normal stigma is differentiating, stamens form a distinctly stigmatoid tip subtended by a short filament bearing the initials of lateral outgrowths. The stigmatoid tip then enlarges to a green, bulbous recurved structure and there is considerable extension growth of the filament. Histological study of developing and mature teratological stamens showed complete absence of sporogenous tissue and also confirmed the true stigmatic nature of the tip region. The results are discussed in relation to regulation of sex determination.
Electropherogram pattern similarity of seed proteins from 21 different soybean (Glycine max) varieties
Authors: Savoy Clifton F.
Published: September 2008

Soybean (Glycine max) seed protein has been characterized using a phosphate-detergent (sodium dodecyl sulfate) polyacrylamide gel electrophoretic system, which has been extensively tested on plant proteins. The same general densitometer electropherogram pattern as regards numbers and kinds of protein components resolved was observed for all soybean varieties tested, and one pattern is presented along with appropriate descriptive characterizations (numbers, molecular weights, relative mobility, and light absorption at 597 nm) to aid in distinguishing the components. Quantitative differences, however, of individual components may occur.
The cultivation of Chondrus crispus. Factors affecting growth under greenhouse conditions
Authors: Neish A. C. , Shacklock P. F. , Fox C. H. , Simpson F. J.
Published: September 2008

Two methods of growing Chondrus crispus in flowing seawater in tanks in a greenhouse were used in determining some of the conditions required for the cultivation of C. crispus. In one system, individual plants were tethered to a fixed support, and in the other, the plants were allowed to float freely in circulating seawater. The addition of nitrate or ammonia and phosphate increased the growth rate, whereas iron did not. Urea was not a good source of nitrogen. Well nourished plants had a relatively high nitrogen and water content and were richly pigmented. Such plants, when grown in nutrient-deficient seawater, gradually bleached and the percentage of dry matter and carrageenan increased. Growth under conditions of continuous illumination was superior to normal illumination with alternating day and night periods. Seasonal variation in growth rates was closely correlated with the mean ambient temperature of the seawater. Epiphytes were a serious problem but became less so as optimum conditions for growth of C. crispus were approached. A single plant (T4), observed to have a relatively rapid growth rate, was selected and a clone was established by vegetative propagation.
Leaf senescence in Maianthemum canadense: the effect of cytokinins and gibberellin
Authors: Horton Roger F.
Published: September 2008

The senescence of leaf disks of Maianthemum canadense var. canadense, measured as the loss of chlorophyll, is retarded by treatment with either cytokinins or gibberellin. Abscisic acid treatment can reduce the senescence-retarding effects of the other regulators. Maianthemum is the first monocotyledenous species in which senescence retardation by gibberellin has been recorded.
Modern pollen rain and vegetation of the St. Elias Mountains, Yukon Territory
Authors: Birks H. J. B.
Published: September 2008

The vegetation of the area east of the Klutlan Glacier in the St. Elias Mountains is described with the methods of European phytosociology. Four major vegetation types are recognized: Picea glauca forests, Populus balsamifera forests, Betula glandulosa shrub–tundra, and Dryas integrifolia tundra.The modern pollen assemblages deposited in these vegetation types are determined by pollen analysis of surface moss polsters, lake muds, and moss samples from sedge swamps. Numerical analyses of the surface spectra indicate that spectra from the Dryas tundra and from the Populus forests are distinctive in their pollen composition. The variation in the percentage pollen content of samples from the Picea forests and the shrub–tundra is so great, even when spectra from a single sample type are considered, that no reliable distinctions can be made in modern pollen spectra from these two community types.
Effect of a host-specific toxin (AM-toxin I) produced by Alternaria mali, an apple pathogen, on the ultrastructure of plasma membrane of cells in apple and Japanese pear leaves
Authors: Park Pyoyun , Tsuda Mitsuya , Hayashi Yoshiharu , Ueno Tamio
Published: September 2008

AM-toxin I (4 μg/ml), a host-specific toxin of Alternaria mali, caused permeability changes in susceptible apple and Nijisseiki pear leaves within 5 min of treatment. The first effect of the toxin appeared on plasma membranes of susceptible apple cells. One hour after toxin treatment, slight invaginations were evident in plasma membranes near plasmodesmata. Six hours after treatment, the spaces between cell wall and invaginated plasma membrane contained lomasome-like vesicles, membranous fragments, and desmotubules extending from plasmodesmata. The membranous materials appeared to originate from the plasma membrane. Thirty-one hours after treatment, necrotic cells of susceptible leaves showed the general disruptions of cellular membranes which might be caused by secondary effects of the toxin. The similar changes of plasma membrane and plasmodesmata also were found in Nijisseiki pear cells treated with AM-toxin I (4 μg/ml) for 1 h and 6 h. The invaginations of the plasma membrane at plasmodesmata were the first ultrastructural modifications in the toxin-treated Nijisseiki cells. AM-toxin I did not affect the ultrastructure of resistant apple and Chojuro pear cells. These results indicate that the initial sites for the toxin may be on the plasma membrane of the susceptible apple cells. Furthermore, the results suggest that the plasma membrane modifications are associated with permeability changes in the toxin-treated, susceptible plant cells except for original host cells treated with the toxin.
Compositional analysis of the photosynthetic membrane system of western hemlock chloroplasts
Authors: DeYoe David R. , Brown Gregory N.
Published: September 2008

The protein, lipid, and fatty acid composition of the thylakoid membrane system of western hemlock (Tsuga heterophylla (Rafn.) Sarg.) chloroplasts was determined. Linear gradient slab gel electrophoresis of SDS-solubilized membrane protein preparations from the thylakoid system and its photosystem I (D144) and II (D10) subfractions resolved 32 protein bands. Density analysis of electrophoretic patterns accompanied by molecular weight determinations distinguished complex I at 63 kilodaltons and complex II at 23 kilodaltons.Sequential extraction of the thylakoid pellet in acetone - ethyl ether (4:1, v/v) and chloroform–methanol (2:1, v/v) followed by gel filtration on lipophilic Sephadex LH-20 provided two major lipid fractions. Qualitative thin-layer chromatography using lipid standards and colorimetric assays revealed the presence of monogalactosyl diglyceride, digalactosyl diglyceride, sulphoquinovosyl diglyceride, phosphatidyl glycerol, phosphatidyl choline, and phosphatidyl inositol. The concentration of each glycerolipid in micromolars per gram fresh weight of needle tissue was 11.16, 9.90, 6.18, 5.25, 3.16, and 2.32, respectively.The fatty acid contingent of each glycerolipid was determined by gas–liquid chromatography using 15% HI–EFF–IBP on Chromosorb W (100–200 mesh). Trimethyl(α, α, α-trifloro-m-tolyl)ammonium hydroxide was used as the 'on-column' active methylating agent. The following fatty acids were present at detectable concentrations in each of the glycerolipids: palmitic (16:0), palmitoleic (16:1), stearic (18:0), oleic (18:1), linoleic (18:2), linolenic (18:3), and 11-eiconsenoic (20:1). The major fatty acids of the phospholipids were 16:0 and 18:1, while the predominant fatty acids of the glycolipids were 18:3, 18:1, and 16:0.Western hemlock thylakoid membrane protein patterns appeared remarkably similar to those demonstrated in numerous plant and algal systems. On the other hand, thylakoid glycerolipids and their respective fatty acids, while qualitatively similar, revealed significant quantitative differences from values reported for herbaceous species.
Soil temperature and drying cycle effects on water relations of Pinus radiata
Authors: Kaufmann Merrill R.
Published: September 2008

The influence of edaphic and atmospheric conditions on the development of plant water stress, water absorption by roots, and transpiration was studied with 2-year-old seedlings of Monterey pine (Pinus radiata D. Don). The slope of the relationship of xylem pressure potential to transpirational flux density was influenced by root temperature. Increased root resistances (separated from viscosity changes of water) occurred at root temperatures of 12 to 13 °C and became more limiting for water absorption at lower temperatures. Transpirational flux density was not affected by root temperature because xylem pressure potentials were not sufficiently low to close stomata. However, at the end of 9- and 12-day drying cycles, transpiration was lower than in well watered controls as a result of stomatal closure. The relationship between xylem pressure potential and transpiration exhibited hysteresis after 9 days of drying, but hysteresis was minimal upon rewatering or in unstressed control plants.
Frequency spectrum analysis of plant storage tissue during deterioration
Authors: Tattar Terry A. , Sylvia David M.
Published: September 2008

Frequency spectra of healthy plant storage tissue indicate that the tissue acts as a high-pass filter that attenuates low frequencies and allows high frequencies to pass through. During progressive deterioration of the tissue from infection of soft-rot bacteria, the frequency spectra indicated a loss in ability of the tissues to filter low frequency signals.
Identification of Vicia seedlings
Authors: Nozzolillo Constance
Published: September 2008

Seedlings of 58 of about 150 species in the genus Vicia (Fabaceae) were grown to the three-eophyll stage. A key, based on readily observable characters such as leaflet shape, number of leaflets per eophyll (seedling leaf), and nodal position of the first eophyll, is presented together with photographs of pressed seedlings. A marked tendency of species regarded as phylogenetically primitive to produce seedlings with bipinnate eophylls having leaflets broader than 2 mm is noted. Conversely, seedlings of more evolved species tend to have multipinnate eophylls with leaflets narrower than 2 mm.
Ultrastructural study of host–parasite interactions. II. Decay of lettuce caused by Botrytis cinerea and phyllosphere bacteria
Authors: Delon René , Kiffer Etienne , Mangenot François
Published: September 2008

Botrytis cinerea causes a fast-spreading soft rot in lettuce that, under favorable conditions, completely destroys the tissues in less than 72 h. Within the first 24 h, the fungus penetrates the cuticle into the foliar parenchyma, destroying the cell wall and cellular content. Dictyosomes and mitochondria are altered and disappear first. Chloroplasts resist longer but are deeply modified with inflating and stacking of thylakoids, an increase in number of osmiophilic globules, and the disintegration of the plastidial membrane. Lomasomes and microbodies appear. Cell walls are made visible by Thiéry's technique. Bacteria invade dead tissues and seem to participate in a more complete destruction of the host and the fungus.
Separation of horseradish peroxidase isoenzymes by preparative polyacrylamide gel electrophoresis
Authors: Saeed Sheikh A. , Cuthbert Josephine
Published: September 2008

Seven peroxidase isoenzymes were purified from crude horseradish peroxidase (EC 1.11.1.7) (HRP) in a single step by preparative polyacrylamide gel electrophoresis. The peroxidase activity in seven isoenzymes accounted for 90% of the activity in the crude material. Each isoenzyme (except HRP7) after separation migrated as a single band with characteristic electrophoretic mobility. All of the purified isoenzymes were found to retain complete peroxidase activity after storage at −20 °C or 4 °C for 3 months.
Anastrophyllum assimile and Marsupella revoluta, new to the interior of North America
Authors: Horton Diana G.
Published: September 2008

Anastrophyllum assimile (Mitt.) Steph. and Marsupella revoluta (Nees) Lindb. are reported from the Keele Peak area, central-eastern Yukon Territory, Canada, and M. revoluta is also reported from Devon Island, Northwest Territories, Canada. These new localities extend a pattern of disjunct occurrences throughout the known range of both species, which further support the hypothesis of their relictual status. However, collections of A. assimile from coastal British Columbia and the Alexander Archipelago, Alaska, are indicative of strong oceanic affinities of North American populations of this species. Also, the arctic and alpine localities at which either A. assimile or M. revoluta might be expected to occur in the interior of Alaska and the Yukon are limited in number as both species invariably occur in association with siliceous substrates.
Temperature relations of gas exchange in altitudinal populations of Taraxacum officinale
Authors: Kemp Paul R. , Williams III George J. , May David S.
Published: September 2008

Taraxacum officinale plants representative of three altitudinally diverse populations were grown under uniform conditions. Temperature responses of net photosynthesis, photorespiration, and transpiration were obtained from four plants of each population over the range of 10 to 40 °C at saturating irradiances(1000 μE ∙ m−2 ∙ s−1). Dark respiration rates were obtained from the same plants over the range of 10 to 30 °C. All plants exhibited similar gas exchange responses to temperature regardless of population origin. Maximum rates of net photosynthesis occurred near 20 °C in all plants and averaged 20.8 mg CO2 ∙ dm−2 ∙ h−1 (mean of 12 plants). Dark respiration and photorespiration rates increased nearly linearly with temperature in all plants. These results are in contrast with previous studies of the same populations in which differences in Hill activity and succinate dehydrogenase activity were reported. However, the photosynthetic patterns and lack of genetic differentiation of photosynthesis are similar to the results obtained for another weedy species, Verbascum thapsus, along the same altitudinal transect.
Cytotaxonomy of Chrysopsis and Heterotheca (Compositae-Astereae): a new interpretation of phylogeny
Authors: Semple John C.
Published: September 2008

The chromosome numbers for 137 populations of 24 species are reported. First reports of n = 5 are given for Chrysopsis decumbens, C. floridana, C. hyssopifolia, C. lanuginosa. C. latisquamea, and C. scabrella and 2n = 18 for C. cruiseana. The occurrence of the diploid 2n = 8 for C. mariana is also reported for the first time. The base number of Heterotheca is x = 9, while the base numbers of Chrysopsis are x = 4 and 5 and.x2 = 9. A realignment of sections included in the two distinct genera is proposed.
Monocyclic Psaronius from the lower Pennsylvanian of the Illinois Basin
Authors: DiMichele William A. , Phillips Tom L.
Published: September 2008

A new species of Psaronius is described from permineralized monocyclic stems with distichous leaf scars. Diameters for the steles are 3.5–4.4 cm, up to 6.5 cm for the stem, and 8 cm for the trunk which includes inner and outer roots; the longest of 11 specimens is 32 cm. These specimens from the lower Pennsylvanian of western Illinois are the oldest known histologically preserved stems and roots for the genus. Psaronius simplicicaulis sp.nov., with its distichous leaf arrangement, is very similar to Mississippian – early Pennsylvanian Megaphyton specimens, indicating that the earliest known marattialean tree ferns were smaller in diameter than their late Pennsylvanian relatives and probably monocyclic with distichous fronds. The middle Pennsylvanian increase in the distribution and abundance of Psaronius generally coincides with increased size, polycyclic stelar anatomy, and polystichy.
A second distinct chlorophyll a – protein complex in maize mesophyll chloroplasts
Authors: Hayden D. B. , Hopkins W. G.
Published: September 2008

A second distinct chlorophyll a – protein complex has been resolved in extracts of maize mesophyll chloroplasts. Resolution was accomplished through modified incubation and electrophoresis and through the use of a mutant deficient of chlorophyll b. This complex, complex IV, has an electrophoretic mobility similar to that of the light-harvesting chlorophyll a/b – protein and chlorophyll a is its major pigment component. Carotenoids are probably also present in this complex. Evidence to date indicates a correlation between the presence of complex IV and photosystem II.
Métabolisme de l'acide indolyl-3-acétique dans les cultures de cellules d'Acer pseudoplatanus cultivés in vitro
Authors: Maillard F. , Zrÿd J.-P.
Published: September 2008

Incubation of cell suspensions of sycamore (Acer pseudoplatanus) with β-indoyl-3-acetic acid (IAA) first led to the formation of IAA-glycosides, then to that of IAA-aspartate. Great differences are observed between the kinetics of IAA transformed by two distinct strains: one, auxin dependent (S), the other, auxin independent (MB). Other degradation products are only found in the culture medium. The localization of IAA-degrading systems in the cell wall is postulated. The auxin requirement of the S strain is discussed.
A revision of Monochaetiella (Deuteromycotina)
Authors: Sutton B. C. , Dicosmo Frank
Published: September 2008

Monochaetiella hyparrheniae Castell. the type of Monochaetiella Castell. is redescribed and illustrated. Monochaetiella themedae Kandasw. & Sundar. and M. cymbopogonis Punith. & Sarwar are separated into Monochaetiellopsis gen.nov. by differences in conidial morphology, conidiogenesis, and acervulus structure. The generic relationships of Monochaetiella and Monochaetiellopsis are discussed.
Ultrastructural studies of ascospore liberation in Pyronema domesticum
Authors: Hung Ching-Yuan
Published: September 2008

Ascospores of Pyronema domesticum contain three distinct spore wall layers. The liberation of ascospores presumably commences immediately after the three spore wall layers are formed. This is evidenced by the fact that vesiculation of the investing membrane was observed at the time when three wall layers could be distinguished. Vesiculation continues until the total disappearance of the perispore. Concurrently the epiplasm of the ascus degenerates and converts into a large vacuole within the ascus. Spores are violently ejected through the apical pore that is surrounded by a weakened apical ring. Presumably eight ascospores are discharged at the same time but do not adhere as a single unit. The operculum is generally not hinged to the main body of the ascus and an ascus without ascospores degenerates.