bluuebunny/crossref_metadata_2025 huggingface dataset:
Xylogénèse chez les dicotylédones arborescentes. III. Transport de l'auxine et activité cambiale dans les jeunes tiges de Hêtre
Authors: Lachaud S. , Bonnemain J. L.
Published: October 2007

The pattern of [3H]-labelled auxin transport has been studied in the beech (Fagus sylvatica L.) (a diffuse-porous tree), in young shoots where the slow basipetal cambial reactivation depends on the buds. At 20 °C, most [3H]-labelled IAA molecules proceed downwards in active shoots as a wave, whose average speed is 13 to 15 cm a day; the velocity of the front being at least 18 to 19 cm a day. The speed of the [3H]-labelled IAA wave depends on the temperature; it is about 7 cm a day at 9 °C, which is the average temperature in the forest during the cambial reactivation period. In natural conditions, the auxin pulse velocity is comparable to that of the cambial reactivation. The ability of tissues to transport auxin at 20 °C depends on the season. During winter rest, the pattern of [3H]-labelled IAA movement is diffusive and very slow. During the 2 months preceding cambial reactivation, the tissues become gradually capable of active auxin transport, the speed and the intensity of which increase at the same time. Microautoradiographs show that the cambium and its differentiating derivatives are the site of auxin transport and also of its utilization: the hormone occupies a preferential site for xylogenesis regulation.
In vitro culture of Bouvardia ternifolia
Authors: Fernandez Leonor , de Jimenez Estela Sanchez
Published: October 2007

Callus cultures were induced from radicle and leaf tissues of Bouvardia ternifolia (trompetilla). Optimum growth regulator concentrations for radicle callus cultures were 1 mg/L 2,4-dichlorophenoxyacetic acid and 0.005 mg/L kinetin; for leaf callus they were either 2 mg/L naphthaleneacetic acid and 0.002 mg/L benzylaminopurine or 5 mg/L of idoleacetic acid and 0.01 mg/L kinetin. Callus has been maintained in culture for nearly 3 years with a very rapid growth rate.A generation time of approximately 24 to 28 h was obtained for batch cell suspension cultures. Production of protoplasts from suspension cultures was optimized with a yield of 70 to 90%. Protoplast culture was achieved in droplets of fresh medium with 2 mg/L napthaleneacetic acid, 0.01 mg/L benzylaminopurine, and0.5 M mannitol. After 2 years, callus in culture still retained its organogenetic capacity. An average of 18 complete plantlets from approximately 2 g of callus can be obtained after transfer to medium with 0.1 mg/L indoleacetic acid and 0.1 mg/L benzylaminopurine.
On the poroid genera of the Tremellaceae
Authors: Bandoni R. , Oberwinkler F. , Wells K.
Published: October 2007

Type specimens and other collections of Aporpium caryae (Schw.) Teixeira and Rogers, Protodaedalea japonica Imazeki, and Protomerulius brasiliensis Möller are described and illustrated. The three taxa are dimitic and have clamp connections and sphaeropedunculate basidia. Gloeocystidia are present in Protomerulius and Protodaedalea but are lacking in Aporpium. The basidiocarp of Protomerulius is subiculate and readily strips from the substrate; that of Aporpium is usually asubiculate and strongly attached. Shelving fructifications, surface features, and unusual basidial form distinguish Protodaedalea.
Effect of phenolic compounds from Eucalyptus on the mycelial growth and conidial germination of Cryphonectria cubensis
Authors: Alfenas A. C. , Hubbes M. , Couto L.
Published: October 2007

Mycelial growth and conidial germination of Cryphonectria cubensis (Bruner) Hodges were inhibited by phenolic compounds of Eucalyptus spp. Inhibitory activity of caffeic, p-coumaric, ferulic, gallic, protocatechuic, gentistic, and benzoic acids varied with the concentration, presence, and numbers of -OH and -OCH3 substituents attached to the aromatic ring of these substances. The possible role of these compounds in the resistance of eucalypts against C. cubensis is discussed.
The composition, diversity, and heterogeneity of some jack pine (Pinus banksiana) stands in northeastern Ontario
Authors: Carleton T. J.
Published: October 2007

Understorey composition, diversity, and interquadrat heterogeneity are examined among a series of 23 jack pine (Pinus banksiana Lamb.) dominated stands in northeastern Ontario. Information on the soils, density, and age structure of the trees was available for each site studied. Composition in both vegetation and soils data sets was explored using detrended correspondence analysis (DCA), an efficient trend seeking ordination technique. Following a rotation to congruence of vegetation axes upon those for soil, variation in the soils data accounted for a maximum of 40–50% variance in the first two axes of the vegetation analysis. Examination of a residual ordination, after soil effects were removed, indicated a primary gradient related to both canopy type and frequency of disturbance by surface fire. Diversity measures, including richness and N2, showed no relationship to stand age, disturbance frequency, or canopy type. Some indefinite patterns appeared with bryophyte diversity. Interquadrat heterogeneity showed no relationship to stand age, canopy type, or disturbance regime as more than one source of spatial pattern was evident among the stands. These results are discussed in relation to the study of succession by indirect methods.
Phytosociological structure of seaweed communities and the invasion of Fucus serratus in Nova Scotia
Authors: Dale Mark
Published: October 2007

A method for analyzing the phytosociological structure of seaweed communities using measured line transects, or line transects with subsidiary point sampling, is described. The methods are applied to communities on the shores of Nova Scotia to investigate the spread of the introduced species, Fucus serratus L., which has been rapid in some areas but slow in others. The study found no evidence that its invasion into new areas has been slowed by competition from Chondrus crispus Stackh., but it did find evidence that competition from Fucus edentatus Pyl. has probably been an important factor.
Seasonal variation of the terpenes of the leaves, buds, and twigs of balsam fir (Abies balsamea)
Authors: Rudloff E. von , Granat M.
Published: October 2007

The variation in the percentages of the volatile terpenes of the leaves, buds, and twigs of balsam fir from Saskatchewan was determined during the course of 2 years. Very little variation was found in mature leaves and twigs throughout the year and also in the buds during winter. Major changes were recorded in the percentages of the main terpenes of the buds 4–6 weeks before bud burst, the newly formed buds in midsummer, and somewhat smaller ones in those of the new leaves from first measurements to midsummer. Except in the newly formed twigs, the twig oil composition varied little through the year, but it was subject to differences outside of the experimental error from one sample to another. The chemosystematic implications are discussed briefly.
Latitudinal differentiation in response to chilling temperatures among populations of three mangroves, Avicennia germinans, Laguncularia racemosa, and Rhizophora mangle, from the western tropical Atlantic and Pacific Panama
Authors: Markley Jonathan L. , McMillan Calvin , Thompson Jr. Guy A.
Published: October 2007

Upon exposure to chilling temperatures, the mangrove populations of Avicennia germinans (L.) L., Languncularia racemosa (L.) Gaertn., and Rhizophora mangle L. showed various amounts of leaf and plant damage that correlated with their latitudinal origin. Populations of more tropical origin showed the most chilling injury and those of more temperate origin showed less injury. The range of variation in dysfunction and chilling injury was widest among Avicennia populations, intermediate among Laguncularia populations, and narrowest among Rhizophora populations, but in each of the three mangroves, populations from northeastern Mexico had greater chilling tolerance than did those from southern Mexico, Belize, or Panama. Populations from Florida had greater chilling tolerance than did those of Jamaica and St. Croix. The most tolerant to chilling treatments were the Avicennia populations of Texas. In both leaves and roots of more tropical Avicennia plants, the lipid extracts had a greater proportion of oleic acid (18:1) and a lesser amount of linoleic (18:2) than in comparable extracts of plants of more temperate origin, but plants of diverse origin showed no consistent changes in the saturation of fatty acids in lipid extracts after chilling. The ratio of 18:2 to 18:1 for Texas plants was significantly greater than for Belize plants that were grown at temperatures above chilling as well as after chilling, suggesting differences in membrane fluidity based on inherent differences in fatty acid composition. Seeds and recently germinated seedlings as well as plants that had been under laboratory conditions for up to 5.5 years continued to show differences in chilling injury; this also suggested that the differentiation is based on inherited properties.
Analysis of the effects of the spotted tentiform leafminer (Phyllonorycter blancardella) on the photosynthetic characteristics of apple leaves
Authors: Proctor J. T. A. , Bodnar J. M. , Blackburn W. J. , Watson R. L.
Published: October 2007

Infestation of apple leaves with the spotted tentiform leafminer (STLM) reduced their net photosynthetic rate (Pn) over a range of light intensities. At a saturating irradiance level of 1240 μE∙m−2∙s−1 and 20 mines per leaf, 32.9% of the leaf area was injured but Pn was decreased by only 23.2%. Examination of parameters in a model for leaf photosynthesis showed a reduction in maximum photosynthetic rate (asymptotic value of the light-response curve) and mesophyll conductance but not in photochemical efficiency or dark respiration. The STLM injury had no effect on transpiration, stomatal conductance, and a slight effect on internal CO2 concentration and water-use efficiency. Mining reduced chlorophyll content of the leaves and this reduced the chlorophyll fluorescence of the mined areas. Tissue around the mines had a relatively high fluorescence reading confirming the Pn measurements and suggesting that this technique was suitable for these and similar studies. Mining by the STLM disrupts the photosynthetic apparatus of the leaf and affects a number of mechanisms in the photosynthetic process. Correlating these effects with field observations will help in determining economic thresholds for this insect.
The effects of ozone and nitrogen fertilizer on tall fescue, ladino clover, and a fescue–clover mixture. I. Growth, regrowth, and forage production
Authors: Montes Ruben A. , Blum Udo , Heagle Allen S.
Published: October 2007

The effects of chronic ozone (O3) and (or) nitrogen fertilizer on growth, regrowth, and forage production of ladino clover (Trifolium repens L. cv. Tillman) and tall fescue (Festuca arundinaceae Schreb. cv. Kentucky 31) grown in pots separately and together in open-top chambers in the field were studied from April 27 to October 19, 1979. Mean 7 h per day (0930 to 1630 EDT) O3 concentrations for this period were as follows: charcoal-filtered air chambers, 0.03 ppm; nonfiltered air chambers (NF-1), 0.05 ppm; nonfiltered air chambers with O3 added for 7 h per day (NF-2), 0.08 ppm; and ambient air, 0.05 ppm. Ozone reduced regrowth (milligrams of dry weight per plant per week) and total forage production of clover and the fescue–clover mixture. The magnitude of the reductions of clover growth and forage production corresponded in general to the O3 levels. Growth of fescue was not significantly modified by O3 treatments. Nitrogen fertilization stimulated the growth of fescue but had little impact on the growth of clover. Nitrogen fertilization did not change the response of either species to O3.
Patterns of decay caused by Inonotus dryophilus (Aphyllophorales: Hymenochaetaceae), a white-pocket rot fungus of oaks
Authors: Otjen Lewis , Blanchette Robert A.
Published: October 2007

Decay of living white oaks (Quercus alba L. and Quercus macrocarpa Michx.) caused by the white-pocket rot fungus Inonotus (Polyporus) dryophilus (Berk.) Murr. was characterized using scanning electron and light microscopy. Delignified tissues lacked middle lamellae and degradation of the cell wall was characterized by the presence of cellulosic macrofibrils. Chemical analyses showed delignified tissues to be composed of 93.47% total sugars and 2.59% lignin, whereas sound heartwood had 64.48% total sugars and 24.99% lignin. Selective delignification occurred in axial parenchyma cells surrounding vessels of earlywood and latewood. Flame-shaped tracts of vessels with accompanying axial parenchyma, present throughout the latewood, provided avenues for radial movement of I. dryophilus. Dense groups of latewood fibers were not degraded. Inonotus dryophilus did not delignify ray parenchyma or adjacent axial parenchyma; instead, a typical white rot, differentiated microscopically by a shot-hole appearance, occurred. Tyloses did not restrict I. dryophilus movement in heartwood vessels of living oaks. Occluded latewood fibers and medullary rays were often left intact forming borders between white pockets.
La première feuille des plantules d'orge. I. Morphogenèse, les épidermes
Authors: Silvy A.
Published: October 2007

This study of the growth of the first leaf was mainly based on epidermal impressions. The cellular arrangements of the primordium found in the caryopsis are already those of the adult blade. Three initiation periods can be distinguished during morphogenesis. The first period consists of the formation of a primordium from the apical growing point. The primordium insertion takes the shape of an incomplete ring around the apex. The second period consists of the initiation of practically the whole blade from an intercalary meristem. At the beginning of this period, longitudinal cellular partitions lead to increasing of the initiation zone and to variations in blade width. The third period includes ligule formation at the bottom of the blade and the formation of the tubular sheath. The sheath grows from a second intercalary meristem as a continuous ring at the level of insertion. The transversal specialization of the tissues takes place immediately after the initiation phase. It is characterized by a basipetal cellular differentiation, more or less early, and results in cellular strand arrangements that are different on each epidermis. Using the foliar area as reference, the stomatal frequency is the same on both faces of the blade.
An ultrastructural comparison of monokaryotic and dikaryotic haustoria formed by the fusiform rust fungus Cronartium quercuum f.sp. fusiforme
Authors: Gray D. J. , Amerson H. V. , Dyke C. G. Van
Published: October 2007

Haustoria formed by the monokaryotic stage of Cronartium quercuum f. sp. fusiforme in Pinus taeda differed from those of the dikaryotic phase in Quercus rubra. Monokaryotic (M) haustorial walls were continuous with the walls of relatively undifferentiated haustorial mother cells. The septate M-haustorial neck and expanded M-haustorial body were separated from the invaginated host plasmalemma by a sheath which was continuous with the host cell wall. Collars encasing sheaths were infrequently observed. Dikaryotic (D) haustoria were morphologically similar to M-haustoria; however, they differed in several respects when examined with TEM. The D-haustorial mother cell wall was thickened at the penetration site but a reduction in the number of wall layers occurred between the thickened portion of the mother cell and the D-haustorium. A darkly staining neckband was present in the wall of the nonseptate D-haustorial neck but was lacking in the M-haustorium. An extensive sheath separated the invaginated host plasmalemma from the D-haustorial wall distally from the neckband. However, the sheath was separated from the D-haustorial wall and from the host cell wall by an invaginated host plasmalemma doubled in the haustorial neck region proximally from the neckband.
Single-spore isolate variation: the effect on varietal designation in Phytophthora megasperma
Authors: Hamm P. B. , Hansen E. M.
Published: October 2007

Eight single zoospore isolates (SSI) were collected from each of 35 parent isolates of Phytophthora megasperma from 14 hosts. Morphological characters, hyphal growth patterns, and growth rate at several temperatures were measured and compared to assess variation of characters among the SSI of each parent. Oogonia, usually with paragynous antheridia, were formed by 94% of the SSI. The number of oogonia formed and the proportion of paragynous to amphigynous antheridia varied among SSI. Some SSI differed significantly from their parent in all characters measured. Oogonium (and oospore) diameter and sporangium shape were relatively consistent, but sporangium size varied widely. Parent isolates could not easily be classified as P. megasperma var. megasperma or P. megasperma var. sojae by oogonium diameter. Of the 35 parent isolates, 43% produced some SSI with oogonia averaging < 45 μm and some with oogonia averaging > 45 μm, the spore diameter used for varietal separation. Basing varieties on oogonium diameter is not justified because of such differences among SSI of a single parent and between wild-type isolates. The results supported a revised description of P. megasperma.
The mechanism of plication inception in palm leaves: histogenetic observations on the palmate leaf of Rhapis excelsa
Authors: Kaplan Donald R. , Dengler Nancy G. , Dengler Ronald E.
Published: October 2007

Plications in the leaf of Rhapis excelsa are initiated at the lateral, basal margin of the palmate lamina and are oriented vertically from inception. When first initiated the plications appear in transection as distinct, sinusoidal folds. However, with the addition of more folds laterally, the earlier pleats become more markedly appressed and constrained to grow more symmetrically in a radial plane. As a result of asymmetry of the entire leaf the cathodic side of the lamina which abuts against the next oldest leaf shows an earlier folding and more radial, symmetrical growth than the anodic, free margin. However, there is no evidence of a significant developmental difference among plications in different regions of the blade. Changes in shape from the unplicated apex of the fold to its markedly plicated base parallel precisely the changes in shape exhibited by a single plication position followed through time. Quantitative observations on plication growth demonstrate that initially there is more extensive upgrowth in the adaxial plication ridges than their abaxial counterparts. But adaxial ridge formation is correlated with cell division whereas abaxial protuberance is the result almost exclusively of cell enlargement. Once a pattern of alternating adaxial and abaxial ridges is established, plication growth shifts from the ridges to the intercostal zones between the ridges and occurs by cell division with no net cell enlargement during the early phases studied. These quantitative observations indicate that increases in plication furrow depth are a result of ridge upgrowth rather than cell separation, and histogenetic observations give no sign of protodermal disruption and redifferentiation. Plication inception in Rhapis is therefore a result of meristem folding and not tissue cleavage. Because quantitative measurements of plication origin and growth in Rhapis are virtually identical to those described in the pinnate palm Chrysalidocarpus lutescens, we conclude that morphogenetic processes are the same and that differing plication shape between them is merely a consequence of physical features within the leaf itself and does not indicate different morphogenetic mechanisms as suggested in the past.
Shoot ontogeny in Fraxinus pennsylvanica (green ash). II. Development of the inflorescence
Authors: Remphrey W. R.
Published: October 2007

From initiation to fruit set, which occurs over three growing seasons, eight stages are recognized in the development of axillary inflorescences in the dioecious species Fraxinus pennsylvanica var. subintegerrima (Vahl) Fern, (green ash). In the first season, buds are initiated in the axils of foliage leaves. As the shoots expand in the following spring, the buds complete their development. Although similar at first, differences begin to emerge between vegetative and inflorescence buds in that the latter produce robust second-order meristems, the incipient paracladia, protruding close to the original apex. After about 3–4 weeks, when the initiation of such buds is complete, the terminal and subtending lateral meristems present on each axis develop into a three-membered cluster of floral buds. There was a mean of 214.3 ± 12.2 floral buds initiated per female inflorescence, and the number generally increased with the length of the associated shoot. A ridge, the incipient perianth, begins to form around the periphery of each rounded floral apex. Male and female floral buds are not distinguishable at this stage, but the inflorescence buds are distinctly different from vegetative buds. The male and female buds then diverge in their development in that an identation forms at the summit of the incipient gynoecium and male buds initiate two or three anthers. By autumn, the gynoecium is distinctly conical, with an orifice at its summit, and the anthers are lobed. There is lobing of the perianth ridge, but in the mature flower distinct organs traceable to such lobes could not readily be identified.
La morphogenèse florale chez le pétunia. II. La fleur normale
Authors: Turlier Marie-France , Alabouvette Josiane
Published: October 2007

The scheme of floral morphogenesis is based on a histocytological analysis of organogenesis. Several points are emphasized: (i) the activity of the meristem during the development of inflorescence, the receptacle, and the placenta is always brought about by the iterative activity of the corpus initials, generating six superposed levels, each of them producing a type of lateral appendage: bract, calyx, corolla, stamens, carpels, and ovarian partitions; (ii) the evolution of cauline components is described: the corpus is responsible for the organogenesis of part of the corolla, the stamens, and the placenta; the second tunica layer is responsible for the calyx, the other part of the corolla, the carpels and reproductive cells, the protoderm of transmitting tissue, and the stigma; (iii) the calyx, corolla, and gynoecium are trifacial, while the stamens are pentafacial and the placenta is axial; (iv) there is no fusion: the calyx, corolla, and gynoecial tubes arise as an extension of the initiation started on separate sites; the corollo-staminal tube results from the elongation of the lower part of the corolla and of the base of the stamen filaments under the zone of interpetalous-corolla initiation; an anticlinal growth, joining face to face, produces the filling of the style. Thus, during flower morphogenesis, organogenous, histogenous, and differentiation patterns begin in well defined places, at given times.
Genetic differentiation, diversity, and inbreeding in the mountain monkeyflower (Mimulus caespitosus) of the Washington Cascades
Authors: Ritland Kermit
Published: October 2007

Mimulus caespitosus is a stoloniferous yellow monkeyflower that grows in small, perennial mountain streams. Plants from 22 populations around the crest of the Cascade Mountains in Washington State were electrophoretically assayed for 15 allozyme loci. Expected heterozygosity within populations (H), a measure of genetic diversity, averaged 0.17 and was negatively correlated with northeastward aspect. No association of H with elevation or position upstream was detected. Wright's gene fixation F averaged 0.19, indicating 20–30% selfing, and was significantly heterogeneous among populations. Nei's genetic distance D averaged 0.072, significantly above average for conspecific populations, especially considering all populations were within 11 km. Populations from the same stream have lowest D, whereas populations from the same mountainside, mountain, and region show increasing values of D. Thus, gene flow is predominant along streams and a hierarchy of genetic relationships exists. It was expected that because this area was heavily glaciated during the Pleistocene, postglacial colonization by refugial populations would result in strong clusters of populations from adjacent streams sharing the same refugia. However, a dendrogram of genetic distances showed few statistically significant clusters of populations from different streams.
Mycoflore des aiguilles de Pinus banksiana et Pinus resinosa. I. Champignons endophytes
Authors: Legault D. , Dessureault M. , Laflamme G.
Published: October 2007

The nature and distribution of the endophytic mycoflora isolated from healthy needles of Pinus banksiana and Pinus resinosa growing in plantations or natural stands infected with Scleroderris canker were investigated. Overall colonization rates of the needles were 68 and 89% for P. banksiana and P. resinosa, respectively, and were generally higher in closed canopy stands. For a given tree, colonization rates increased with foliage age but were not influenced by twig orientation. Colonization rates by more than one fungal species were 17% for P. banksiana and 76% for P. resinosa. Two different endophytic species could be found inside the needles of P. banksiana and up to seven in P. resinosa. Brunchorstia pinea, causal agent of Scleroderris canker, was not isolated. Commonly isolated endophytic fungi show a strong preference toward their host: the endophytic mycoflora of P. banksiana needles is almost limited to Coccomyces sp. while Pragmopycnis sp. and three Leptostroma species account for most of the isolates from P. resinosa.
Mycoflora of Pinus banksiana and Pinus resinosa needles. II. Epiphytic fungi
Authors: Legault D. , Dessureault M. , Laflamme G.
Published: October 2007

The epiphytic mycoflora isolated from healthy needles of Pinus banksiana and Pinus resinosa was investigated. Approximately 75% of the fungi were present on less than 5% of the needles. The number of different fungi per needle increased with needle age on both species, but more fungi were found on P. resinosa needles. The most frequently isolated species were common primary saprophytes nonspecific to Pinus: Alternaria alternata, Botrytis cinerea, Cladosporium cladosporioides, Cladosporium herbarum, Epicoccum purpurascens, and Hormonema dematioides. Aureobasidium microstictum, Penicillium brevicompactum, P. spinulosum, and Pithomyces chartarum are reported for the first time in the phylloplane of Pinus.
Seasonal changes in the germination responses of buried seeds of Barbarea vulgaris
Authors: Baskin Jerry M. , Baskin Carol C.
Published: October 2007

In light, fresh seeds of Barbarea vulgaris germinated to 33–62% at 30:15 and 35:20 °C, and 0–5% at 15:5, 20:10, and 25:15 °C; in darkness, they germinated to 0–5% at all thermoperiods. Seeds were buried in pots of soil in mid-July 1983 and 1984 and kept in a greenhouse without temperature controls. Beginning on 1 August, seeds were exhumed monthly for 26.5 (1983 seeds) and 30.5 (1984 seeds) months and tested in light and darkness over the range of thermoperiods. Seeds after-ripened rapidly during the first 2 weeks of burial, and in August they germinated to 65 – 100% at all thermoperiods in light, but to only 0–3% in darkness. Throughout the study, seeds tested in light at the respective monthly thermoperiod germinated to 83 – 100% from April to October and to 45 – 100% in November and March. Thus, seeds brought to the soil surface at any time during the growing season can germinate when soil moisture is nonlimiting. Exhumed seeds germinated to 1 – 77% in darkness at July and August temperatures (35:20 °C) during July and August; however, they did not germinate while buried.
Accumulation of free proline in sorghum (Sorghum bicolor) pollen
Authors: Lansac A. R. , Sullivan C. Y. , Johnson B. E.
Published: October 2007

Suboptimal temperatures cause grain yield reductions generally associated with low seed-set in sorghum [Sorghum bicolor (L.) Moench]. Low proline concentration in pollen has been associated with cold-induced male sterility. This study was done to (i) determine free proline concentrations in grain sorghum pollen after low temperature exposure, (ii) determine the relationship between seed-set and proline concentration in pollen, and (iii) determine the association of proline concentration in pollen with grain yield in sorghums of different maturity. Eleven sorghum genotypes, grown in a greenhouse at 27/22 °C (day/night) until the early boot stage were transferred to 20/10 °C in growth chamber until physiological maturity. Concentration of proline in pollen was determined at anthesis and related to seed number and grain yield. Proline concentrations in pollen increased from 19 to 36 μg∙mg−1fresh wt. to 30 to 49 μg∙mg−1fresh wt. at low temperatures. Seed number and grain yield were reduced by low temperature in most of the genotypes. Percent seed-set in male sterile lines was significantly correlated (r = 0.45**) with free proline concentrations in the pollen from 13 fertile hybrids grown under cold or control conditions. Higher concentrations of proline in pollen under cool and also control temperatures seemingly contribute to greater pollen viability in grain sorghum. In 21 sorghum hybrids grown under control temperatures, seed number per panicle was found correlated (r = 0.42*) to free proline concentrations in pollen. Genotypic differences in pollen proline concentration were not associated with differences between maturity groups. Keywords: Sorghum bicolor (L.) Moench, pollen, free proline, low temperatures, seed-set, grain yield.
Movement of tomato mosaic virus strains inGomphrena globosaas related to temperature sensitivity and plant resistance
Authors: French Christopher J. , Elder Maureen
Published: October 2007

Symptom development, virus multiplication, and distribution of tomato mosaic virus strains L and LS1were compared at 22 and 32 °C in the C4plant Gomphrena globosa. In inoculated leaves, LS1accumulation was much lower at 32 °C compared with 22 °C, whereas the levels of L were similar at both temperatures. At 22 °C, spread of L and LS1from inoculated to uninoculated leaves (systemic movement) was dependent on the stage of plant development and the leaf inoculated. Under all conditions tested, LS1accumulated at a much lower level than L. Under specific conditions of leaf and plant age, LS1was confined to the inoculated leaf, whereas L moved systemically in all experiments. In a mixed infection with tobacco mosaic virus U1strain, LS1did not affect movement of U1within the inoculated leaf but inhibited systemic spread. In Gomphrena, the single amino acid difference in the 30-kDa movement protein of LS1relative to L induced plant resistance to systemic spread of virus. Keywords: systemic movement, local lesion.
Isoetes ×pseudotruncata, a new triploid hybrid from western Canada and Alaska
Authors: Britton Donald M. , Brunton Daniel F.
Published: October 2007

A new interspecific Isoetes hybrid, I. echinospora Dur. ×I. maritima Underw., is described from Vancouver Island, British Columbia and southern Alaska by means of cytology and the scanning electron microscopy of spores. Isoetes ×pseudotruncata D.M. Britton and D.F. Brunton, hyb.nov. is the name proposed for this taxon. It is triploid and produces only aborted, sterile spores and has spore ornamentation features intermediate between those of its putative parents. Several concentrations of hybrids have been identified, each growing with both parents in shallow, freshwater habitat along the Pacific Coast of northwestern North America. Keywords: Isoetes echinospora, Isoetes maritima, hybrid, British Columbia.
Needle ultrastructure and starch content in Scots pine and Norway spruce after ozone fumigation
Authors: Holopainen Toini , Anttonen Seija , Palomäki Virpi , Kainulainen Pirjo , Holopainen Jarmo K.
Published: October 2007

The ultrastructure of current and previous year needles of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies L.) Karst. was studied after exposures to several different ozone concentrations (100 to 600 nL∙L−1) and doses in a chamber system. The ultrastructural changes observed in different experiments in both of these species were qualitatively very similar. Changes were observed in the mesophyll tissue, in which increased density of chloroplast stroma and an increase of ribosome-like granules were the early symptoms, followed by a decrease of the size of chloroplasts and starch grains. Simultaneously a decline of needle starch content could be measured. After fumigation with the lower concentrations, hypertrophy of microbodies were also apparent. When the seedlings were fumigated with the highest concentration (600 nL∙L−1) a subsequent disintegration of cytoplasm and other cell organelles and finally a collapse of the contents of the mesophyll cells, leading to visible injuries, was found. Scots pine nursery stock seedlings appeared to be about equal in sensitivity to ozone as Norway spruce clonal stock. The spruce clones showed differences in sensitivity to the ozone fumigations. Since the observed symptoms are consistent in two species through a concentration gradient of ozone, and also agree with the information dealing with ozone injuries in literature, it is possible to use ultrastructural observations for diagnosing the presence of ozone injuries. Keywords: ozone, Picea abies, Pinus sylvestris, needle ultrastructure, starch.
New species of Laboulbeniales (Fungi, Ascomycetes) from Sulawesi, Indonesia
Authors: Rossi Walter , Weir Alex
Published: October 2007

Four new species of Laboulbeniales occurring on beetles (Coleoptera) from Sulawesi (Celebes), Indonesia, are described and illustrated: Cucujomyces celebensis sp.nov. parasitic on Hyliota sp. (Cucujoidea, Cucujidae), Dimeromyces storkii sp.nov. parasitic on Eustra matanga Andrewes and Eustra plagiata Schm.-Goebel (Carabidae, Paussinae), Laboulbenia hammondii sp.nov. parasitic on Omadius spp. (Cleridae), and Rickia anthribidicola sp.nov. parasitic on Hypseus vestitus Jordan (Anthribidae, Anthribinae). All of the new species are compared with existing taxa. Of particular note is R. anthribidicola, which represents the first confirmed instance of parasitization by a laboulbenialean fungus on members of the hyperdiverse beetle family Anthribidae. Keywords: Laboulbeniales, Indonesia, Anthribidae.
Effects of balsam poplar (Populus balsamifera) tannins and low molecular weight phenolics on microbial activity in taiga floodplain soil: implications for changes in N cycling during succession
Authors: Schimel Joshua P. , Cleve Keith Van , Cates Rex G. , Clausen Thomas P. , Reichardt Paul B.
Published: October 2007

The transition from alder (Alnus tenuifolia) to balsam poplar (Populus balsamifera) is a critical turning point in primary succession on river floodplains in interior Alaska. Associated with the change in plant species are large changes in N cycling. N-fixation and nitrification decrease and the system becomes N-limited, with NH4+ dominating the inorganic N pool. Balsam poplar leaves contain large quantities of tannins and low molecular weight phenolic compounds. We evaluated the effect of these compounds on microbial respiration and N cycling in laboratory assays on soils from an alder-dominated site. Plant compounds were purified and applied to silica gel as an inert carrier. Both tannins and phenolics caused net N-immobilization over a 30-day assay. However, tannins inhibited respiration while phenolics stimulated it. There were no specific effects on nitrification. Thus, tannins acted as a general microbial inhibitor, while phenolics acted as a growth substrate. By inhibiting mineralization while stimulating immobilization, poplar secondary compounds may reduce soil N-availability during the transition betwen alder and poplar stages in succession. Keywords: respiration, mineralization, tannins, secondary chemicals, succession, plant–microbe interactions.
Differences in plant size and flower production between hermaphrodites and females of two gynodioecious Chionographis (Liliaceae)
Authors: Maki Masayuki
Published: October 2007

Plant size and flower production were compared between female and hermaphroditic plants of two gynodioecious Chionographis. Frequency distribution of size and minimum size class of flowering plants were not different between two sex morphs in both Chionographis. In C. japonica ssp. hisauchiana, females produced more ovuliferous flowers than hermaphrodites, although the total number of flowers were not significantly different between two sex morphs. In contrast, hermaphrodites of C. japonica var. kurohimensis exceeded females in the total number of flowers, whereas the number of ovuliferous flowers was not significantly different between two sex morphs. Reproductive effort at flowering season is not different between females and hermaphrodites. These little differences in secondary sex characters, compared with dioecious species, are probably due to the selfing of hermaphrodites and weaknesses in gender specialization. Keywords: Chionographis, flower production, gynodioecy, plant size, secondary sex characters.
Shedding of the Endothelial Glycocalyx in Patients Undergoing Major Vascular Surgery With Global and Regional Ischemia
Authors: Rehm Markus , Bruegger Dirk , Christ Frank , Conzen Peter , Thiel Manfred , Jacob Matthias , Chappell Daniel , Stoeckelhuber Mechthild , Welsch Ulrich , Reichart Bruno , Peter Klaus , Becker Bernhard F.
Published: October 2007

Background—

The astonishing thickness of the endothelial glycocalyx, which rivals that of endothelial cells in the microvasculature, was disclosed in the last 15 years. As already demonstrated, this structure plays a key role in the regulation of inflammation and vascular permeability.

Methods and Results—

Two components of the glycocalyx, syndecan-1 and heparan sulfate, were measured in arterial blood of 18 patients undergoing surgery of the ascending aorta with cardiopulmonary bypass (n=12 with and n=6 without deep hypothermic circulatory arrest) and of 14 patients undergoing surgery for infrarenal aortic aneurysm. Basal values of syndecan-1 (1.2 μg/dL) and heparan sulfate (590 μg/dL) of patients were similar to those of control subjects. Anesthesia and initiation of surgery caused no changes. Global ischemia with circulatory arrest (n=12) was followed by transient 42- and 10-fold increases in syndecan-1 and heparan sulfate, respectively, during early reperfusion (0 to 15 minutes). After regional ischemia of heart and lungs (cardiopulmonary bypass; n=6), syndecan-1 increased 65-fold, and heparan sulfate increased 19-fold. Infrarenal ischemia was followed by 15- and 3-fold increases, respectively (n=14). The early postischemic rises were positively correlated (
r
=0.76,
P
<0.001). Plasma concentrations of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 did not change. Circulating polymorphonuclear granulocytes and the level of postischemic heparan sulfate corresponded negatively. Immunohistochemical imaging and immunoassay of isolated hearts (guinea pig) substantiated syndecan-1 and heparan sulfate as components of the endothelial glycocalyx released into the coronary venous effluent. Electron microscopy revealed shedding of the glycocalyx after ischemia/reperfusion.

Conclusions—

This study provides the first evidence in humans for shedding of the endothelial glycocalyx during ischemia/reperfusion procedures.
Sustained Ventricular Tachycardia Associated With Corrective Valve Surgery
Authors: Eckart Robert E. , Hruczkowski Tomasz W. , Tedrow Usha B. , Koplan Bruce A. , Epstein Laurence M. , Stevenson William G.
Published: October 2007

Background—

The causes of sustained monomorphic ventricular tachycardia (VT) after cardiac valve surgeries have not been studied extensively, although bundle-branch reentry has been reported.

Methods and Results—

Records of 496 patients referred for electrophysiology study and catheter ablation of recurrent VT were reviewed. Twenty patients (4%) had VT after aortic or mitral valve surgery in the absence of known myocardial infarction. The median age was 53 years, and the median ejection fraction was 45%. In 4 patients, VT occurred early after surgery, and electrophysiology study was performed 3 to 10 days later. In the remaining patients, electrophysiology study was performed a median of 12 years (interquartile range 5 to 15 years) after surgery. Sustained VT was inducible in 17 patients. VT was attributed to scar-related reentry in 14 patients (70%) and to bundle-branch reentry in 2 (10%). Multiple VTs were present in 9 of 14 patients with scar-related reentry. A total of 42 induced VTs were targeted for ablation. Of the 14 patients with scar-related reentry, 9 (64%) had periannular scar, and 10 (71%) had an identifiable endocardial circuit isthmus. Ablation abolished 41 (98%) of the 42 targeted VTs. At a median follow-up of 2.1 years, 3 deaths occurred 8 to 14 months after ablation. One patient with incessant VT early after valve surgery suffered a stroke with residual hemianopsia. Of the 20 patients, 3 required repeat ablation after recurrence, and 2 of these who were not inducible during electrophysiology study had clinical recurrence that necessitated ablation.

Conclusions—

Sustained VT after valve surgery appears to be bimodal in presentation, occurring either early after surgery or years later. In this referral population, reentry in a region of scar is more common than bundle-branch reentry. Catheter ablation can be successful.
Apolipoprotein A-II Is Inversely Associated With Risk of Future Coronary Artery Disease
Authors: Birjmohun Rakesh S. , Dallinga-Thie Geesje M. , Kuivenhoven Jan Albert , Stroes Erik S.G. , Otvos James D. , Wareham Nicholas J. , Luben Robert , Kastelein John J.P. , Khaw Kay-Tee , Boekholdt S. Matthijs
Published: October 2007

Background—

Although the vasculoprotective effects of apolipoprotein A-I (apoA-I), the major protein associated with high-density lipoprotein, have been universally accepted, apoA-II has been suggested to have poor antiatherogenic or even proatherogenic properties. To study this suggestion more closely, we evaluated how serum levels of apoA-II and apoA-I relate to the risk of future coronary artery disease (CAD) in a large, prospective study.

Methods and Results—

We performed a nested case-control study in the prospective EPIC-Norfolk (European Prospective Investigation into Cancer and Nutrition–Norfolk) cohort. Case subjects (n=912) were apparently healthy men and women aged 45 to 79 years who developed fatal or nonfatal CAD during a mean follow-up of 6 years. Control subjects (n=1635) were matched by age, gender, and enrollment time. Conditional logistic regression was used to quantify the relationship between serum apoA-II levels and risk of CAD. Serum apoA-II concentration was significantly lower in case subjects (34.5±6.3 mg/dL) than in control subjects (35.2±5.8 mg/dL) and was inversely associated with risk of CAD, such that patients in the upper quartile (>38.1 mg/dL) had an odds ratio of 0.59 (95% confidence interval 0.46 to 0.76) versus those in the lowest quartile (<31.1 mg/dL;
P
for linearity <0.0001). After adjustment for fasting time, alcohol use, and cardiovascular risk factors (systolic blood pressure, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, body mass index, smoking, diabetes mellitus, and C-reactive protein), the corresponding risk estimate was 0.48 (95% confidence interval 0.34 to 0.67,
P
for linearity <0.0001). Surprisingly, additional adjustment for serum apoA-I levels did not affect risk prediction of apoA-II for future CAD (odds ratio 0.49, 95% confidence interval 0.34 to 0.68,
P
for linearity <0.0001). Also, after adjustment for high-density lipoprotein particle number and size, apoA-II was still associated with the risk of future CAD (odds ratio 0.62, 95% confidence interval 0.43 to 0.90,
P
for linearity 0.02).

Conclusions—

ApoA-II is associated with a decreased risk of future CAD in apparently healthy people. These findings imply that apoA-II itself exerts effects on specific antiatherogenic pathways. On the basis of these findings, discussion of the potential proatherogenic effects of apoA-II can cease.
International Graduate Education and Innovation: Evidence and Issues for East Asian Technology Policy
Authors: Maskus Keith E. , Mobarak Ahmed Mushfiq , Stuen Eric T.
Published: October 2007

We discuss the policy questions and debate surrounding the role of international (foreign-born) graduate students in the productivity of universities, particularly in the United States. Concerns about national security have induced U.S. immigration authorities to limit the number of foreign doctoral students in science and engineering (S&E) departments in American research universities. This policy has reduced such enrollments beyond the decline already in evidence. Many university officials and business leaders are concerned that this reduction in foreign S&E students will damage domestic research capabilities and broader economic innovation. We review two recent studies of how the presence of international graduate students contributes to scientific journal publications and patents awarded to universities. Both studies, one using macro time-series data and one using micro student-level panel data, find strongly positive impacts, suggesting that limited access to foreign students could diminish knowledge creation and innovation. We then relate these results to educational and innovation policy in key East Asian economies. These nations have an opportunity to increase their enrollments of S&E students, which should enhance their own innovation capacities. However, to achieve full growth benefits from such changes in visa policy, governments need to ensure their economies are conducive to robust and competitive innovation processes.
Simulation and Modeling Bandwidth Control in Wireless Healthcare Information Systems
Authors: Vergados Dimitrios D.
Published: October 2007

Next generation wireless networks have been designed to provide support for multimedia services, with different traffic characteristics and different Quality of Service (QoS) guarantees. Medical broadband applications have attracted increased attention in recent years and furthermore, the tremendous growth of wireless technologies has introduced the potential of continuous healthcare monitoring for mobile patients. The bandwidth requirements and the emergency nature of medical applications introduce the need for QoS provisioning in wireless broadband medical networks. Wireless networks may support a number of e-health applications with different traffic requirements and characteristics, providing at the same time QoS guarantees. Resource allocation in e-health application is inherently different in many aspects including the offered services, traffic requirements, propagation characteristics, and network structure. In this paper, an adaptive resource allocation scheme for QoS provisioning in wireless healthcare information systems is proposed.