bluuebunny/crossref_metadata_2025 huggingface dataset:
THE BIOLOGY OF MYCORRHIZA IN THE ERICACEAE: I. THE ISOLATION OF THE ENDOPHYTE AND SYNTHESIS OF MYCORRHIZAS IN ASEPTIC CULTURE
Authors: PEARSON V. , READ D. J.
Published: May 2006

Techniques are described for the isolation of fungi inhabiting ericaceous roots and for the culture of mycorrhizas under aseptic conditions. The mycorrhizal status of a range of isolates is assessed and the distinctive features of the true endophyte are described. The biology of this fungus is considered with special reference to host specificity and its occurrence as a free living soil micro‐organism.
BASIDIOCARPS ASSOCIATED WITH ERICOID MYCORRHIZAS
Authors: SEVIOUR R. J. , WILLING R. R. , CHILVERS G. A.
Published: May 2006

A species of basidiocarp has been seen in constant and specific association with mycorrhizal Ericaceae. These basidiocarps are shown to be serologically related to pelotons of the mycorrhizal fungus.
SYMBIOTIC GERMINATION OF SOME AUSTRALIAN TERRESTRIAL ORCHIDS
Authors: WARCUP J. H.
Published: May 2006

In symbiosis tests on an agar medium with powdered cellulose as carbon source, isolates of several species of Tulasnella and of Ceratobasidium cornigerum were compared on seven species of Thelymitra and two each of Diuris and Pterostylis. The Pterostylis species were stimulated to germinate only by Ceratobasidium cornigerum, the Diuris species only by Tulasnella calospora but, in general, the Thelymitra species were stimulated by more than one species of Tulasnella, but not markedly by Ceratobasidium cornigerum. These results correlate well with specificities noted in isolations from the roots of mature orchids of these genera in nature.

It was found that different isolates of Tulasnella calospora differed markedly in the efficiency with which they stimulated germination of the species of Diuris and Thelymitra. The most efficient isolates were not necessarily those isolated from these orchids.
HYBRIDS BETWEEN LOLIUM PERENNE L. AND FESTUCA PRATENSIS HUDS. I. CROSSING AND INCOMPATIBILITY
Authors: GYMER P. T. , WHITTINGTON W. J.
Published: May 2006

Natural hybrids between Lolium perenne and Festuca pratensis occur in old grassland; diploids and two types of triploids, festucoid and loloid, may occur. Attempts were made to produce similar hybrids experimentally, both by crossing in the glasshouse, and in mixed plots in the field. It was found very difficult to produce F1 hybrids, except for the production of festucoid triploids by crossing diploid Lolium with tetraploid Festuca. No triploids were obtained from diploid‐diploid crosses, but there was evidence of unreduced gametes in the appearance of tetraploid progeny from diploid–tetraploid crosses within Lolium perenne.

The hybrids were found to be nearly sterile, but attempts to backcross in the glasshouse yielded a few progeny, both from diploids and triploids. Lolium was a much more successful pollen parent than Festuca. The progeny from diploids were mostly diploid, but included a few triploids and aneuploids. Triploid hybrids produced a wide range of progeny, varying from fourteen to twenty‐eight chromosomes.

The difficulty of crossing, and reciprocal differences in compatibility which occur are apparently due to seed incompatibility, probably controlled by the relationship between the genomes and the plasmon in the endosperm.

It is concluded that the abundance of hybrids in natural populations must be explained ecologically.
THE EFFECT OF ROOT PRUNING AND 6‐BENZYL‐AMINOPURINE ON THE CHLOROPHYLL CONTENT, 14CO2 FIXATION AND THE SHOOT/ROOT RATIO IN SEEDLINGS OF PISVM SATIVUM L.
Authors: McDAVID C. R. , SAGAR G. R. , MARSHALL C.
Published: May 2006

Pruning the roots of light‐grown pea seedlings every 4 days accelerated senescence of older leaves and reduced their rate of fixation of 14CO2. Application of 6‐benzylaminopurine to the shoot largely compensated for root removal and increased the shoot/root ratio of both pruned and intact plants. It is suggested that the supply of cytokinins from root to shoot may affect leaves by delaying senescence and maintaining their capacity for photosynthesis; it may also alter the distribution of dry matter within the plant by influencing the proportion of assimilates and other metabolites retained by the shoot.
PERMEABILITY TO WATER OF THE ROOTS OF FIVE HERBACEOUS SPECIES
Authors: NEWMAN E. I.
Published: May 2006

The permeability to water of whole detopped root systems of five herbaceous species, all grown under the same conditions, was determined by the solution‐change method of Arisz, Helder and van Nie (1951). Measurements of root dimensions allowed permeability to be expressed per unit of (a) root surface area, (b) endodermis area, (c) root volume, and (d) root length. By any of these four methods of calculation there were large differences in permeability between the species. Per unit surface area the permeabilities were: broad bean, 0·54; dwarf bean, 0·56; sunflower, 0·71; maize, 2·2; tomato, 6·1 nm second‐1 bar‐1. These differences cannot be explained by any obvious difference in root morphology. The permeability values fit with two previously proposed theories; (1) that much of the root resistance lies in the endodermis; and (2) that the resistance of the soil in the rhizosphere is small compared with that of the plant until the soil has dried to near or beyond the permanent wilting point.
INTERACTIONS OF LIGHT AND TEMPERATURE ON THE GERMINATION OF PLANTAGO MARITIMA L.
Authors: ARNOLD SYLVIA M.
Published: May 2006

The percentage of seeds of Plantago maritima which germinated in the light increased linearly with temperature between 8 and 18° C. The response to fluctuating temperatures could be accounted for entirely by this linear relation. Germination was inhibited when seeds were kept in darkness during ihibition and percentage germination was shown to depend on the temperature of the seeds as well as the length of the dark period. Exposure to light at 25° C released the inhibition of some of the dark treated seeds but exposure to low temperature was ineffectual. Most of the seed came from Upper Teesdale but seed from Devon responded to germination tests in the same way. The germination of seeds of Kobresia simpliciuscula from Teesdale was also inhibited by darkness during imbibition. This type of response may promote the survival of seedlings in their natural environment.
APPARATUS TO MEASURE THE RATE OF FALL OF WIND‐DISPERSED SEEDS
Authors: SHELDON J. C. , LAWRENCE J. T.
Published: May 2006

Apparatus is described for accurately measuring the rate of fall of wind‐dispersed seeds over known distances. The detection system consists of photo‐electric beams at the open ends of a Perspex tube. The apparatus was connected to an automatic timing counter which was switched on by the released seed breaking the uppermost photo‐electric beam, and switched off as the seed passed through the lower beam. A simplified circuit diagram of the detection system is given.
THE ROLE OF TAXIMETRICS IN ANGIOSPERM TAXONOMY II. PARALLEL TAXIMETRIC AND ORTHODOX STUDIES IN CROTALARIA L.
Authors: BISBY F. A. , POLHILL R. M.
Published: May 2006

This paper indicates one way in which taximetrics can contribute to the taxonomic work currently being carried out in herbaria and universities. Taximetric and orthodox studies of African species of Crotalaria L. (Leguminosae) carried out separately by the two authors produced classifications which were similar in essential features. It was possible to resolve twenty discrepancies between the two classifications which varied from the delimitation of major groupings to the placing of individual species and the treatment of outliers. In some cases Polhill's orthodox scheme was upheld and in others Bisby's taximetric results provided evidence for making improvements. The outcome was an amended classification for which the nomenclatural changes are set out.

The authors suggest that parallel studies of this sort may prove one of the most useful contributions that taximetrics can make. Not only is maximum use made of both types of procedure but also such studies contribute to knowledge of the relative performance of the taximetric and orthodox procedures. Only when there is much more confidence and experience in using taximetric procedures will it be useful to apply them in situations where there is no immediate check from orthodox work.
THE HOST‐PARASITE RELATIONSHIP BETWEEN ZIZANIA CADUCIFLORA TURCZ. AND USTILAGO ESCULENTA P. HENN. I. STRUCTURE AND DEVELOPMENT OF THE HOST AND HOST–PARASITE COMBINATION
Authors: CHAN YUK‐SIM , THROWER L. B.
Published: May 2006

Infection of the flowering culm of Zizania caduciflora by the smut fungus, Ustilago esculenta, results in a swollen structure named‘gau sun’This host‐parasite combination is culivated as a vegetable in eastern Asia. The structure and development of gau sun is described and terms are denned to describe developmental stages. The swollen culm (gau sun) has a volume 517 × that of the unswollen culm and contains 2‐9 × the number of cells which are 14‐9 × the volume of those in the unswollen culm. Mucilaginous cavities, absent from the unswollen culm, make up 16% of the total volume of the swollen culm.
FLORAL SEX RATIOS IN ANDROMONOECIOUS UMBELLIFERAE
Authors: DOUST J. LOVETT
Published: May 2006

The distribution of hermaphrodite and male flowers was determined in the inflorescences of three andromonoecious species of Umbelliferae, Smyrnium olusatrum, Pastinaca sativa and Anthriscus sylvestris. Despite wide differences in the number of flowers produced per plant by the three species the floral ratio 4 male to 1 hermaphrodite was remarkably constant and except in an extreme environment 55 to 70 % of hermaphrodite flowers produced ripe seeds. The constancy in floral ratio per plant was maintained by quite different distributions of flower type between umbels in the three species. The apparent contradiction between protandry in flowers but protogyny within umbels is interpreted as an avoidance of simultaneous competition for resources within the plant.
SEASONAL OCCURRENCE OF AN ANTIMICROBIAL FLAVANONE, SAKURANETIN, ASSOCIATED WITH GLANDS ON LEAVES OF RIBES NIGRUM
Authors: ATKINSON P. , BLAKEMAN J. P.
Published: May 2006

Sakuranetin, a flavanone aglycone, was present in glands on the adaxial surfaces of leaves of most varieties of Ribes nigrum L. These glands senesce early in the season, releasing their contents on to the surface of the leaf. Glands on the abaxial surfaces of leaves, which are different in structure from those of adaxial surfaces, do not contain sakuranetin. Conidia of Botrytis cinerea Pers. ex Fr. were inhibited from germinating on adaxial but not on abaxial surfaces of leaves at the time of adaxial gland senescence. Later in the season there was no inhibition of germination of conidia on either leaf surface. Because of the low activity of sakuranetin in vitro it was concluded that other factors were also likely to affect germination of conidia on adaxial leaf surfaces.
GENETIC DIFFERENTIATION OF THE MICROSPECIES SALICORNIA EUROPAEA L. (SENSU STRICTO) AND S. RAMOSISSIMA, J. WOODS
Authors: JEFFERIES R. L. , GOTTLIEB L. D.
Published: May 2006

Electrophoretic variability was examined in 15 natural populations of Salicornia europaea and Salicornia ramosissima, two nearly indistinguishable, diploid, annual plant species common in salt marshes in England and Europe. All of the 800 plants examined were homozygous at the 30 loci which were scored and the number of isozymes for each of the enzyme systems was the same in all individuals. The electrophoretic mobilities of 24 of the enzymes were identical in all plants. With respect to the gene loci coding the other six enzymes, only two classes of individuals were detected: a plant possessed either one set of alleles, or an alternate set for the sis loci. One electrophoretic pattern was found primarily in individuals from the upper levels of salt marshes, whereas the other pattern was common in plants from the lower levels. The two patterns are characteristic of Salicornia ramosissima and Salicornia europaea respectively. The electrophoretic evidence confirms the reproductive isolation of the species, indicates an apparent lack of genetic variability in both of them and simplifies the interpretation of the ecological differentiation.
SEASONAL VARIATION IN NITROGEN AVAILABILITY AND UTILIZATION IN AN ACIDIC AND CALCAREOUS SOIL
Authors: TAYLOR A. A. , DE‐FELICE J. , HAVILL D. C.
Published: May 2006

Pronounced seasonal trends were observed in nitrogen availability and utilization in an acidic soil supporting Deschampsia flexuosa and a calcareous soil supporting Zerna erecta. In both soils, mineralization rates and instant inorganic nitrogen concentrations were maximum in late winter/early spring after which a rapid decline occurred. A similar seasonal pattern was evident in the levels of several nitrogen‐assimilating enzymes and soluble nitrogen pools in both grasses. Fertilizer experiments indicated that in both soil types nitrate formation was limited by the ammonium supply. Despite differences in the major form of inorganic nitrogen supplied to the plants, Deschampsia and Zerna showed similar capacities to utilize ammonium and nitrate. It is suggested that the observed seasonal enzymic response in these native species may be an adaptation to the fluctuating and low nitrogen status of natural soils.
REPLACEMENT OF LEAF PRIMORDIA WITH IAA IN THE INDUCTION OF VASCULAR DIFFERENTIATION IN THE STEM OF COLUCUS
Authors: BRUCK D. K. , PAOLILLO D. J.
Published: May 2006

Summary

Removal of a leaf of Coleus before or early in the differentiation of leaf traces severely reduced vascular differentiation in the subjacent internode. Auxin (IAA) in anion exchange beads (applied on 2 out of every 3 d for 2 to 4 weeks) restored normal structure with respect to arrangement of leaf traces and their composition, size, and rate of development. That IAA is the likely leaf‐limiting factor for vascular differentiation in situ is suggested by the formation of normal quantities of procambium, phloem and xylem under the influence of IAA after leaf excision. However, some peculiarities were induced as well. Plants treated with IAA showed earlier xylem maturation in side bundles, earlier and more frequent differentiation of xylem opposite putative phloem‐only bundles, and corner‐trace xylem connections at the node of IAA application. These can be accounted for by a lack of well‐defined channelling of IAA through petiolar tissues when IAA was applied to the cut surface after leaf excision. Phloem‐only bundles are regarded as an early auxin‐deficient stage in collateral bundle formation, which depends on auxin availability to the bundle for fulfillment.
SENSITIVITY OF FOREST PLANT REPRODUCTION TO LONG RANGE TRANSPORTED AIR POLLUTANTS: IN VITRO AND IN VIVO SENSITIVITY OF OENOTHERA PARVIFLORA L. POLLEN TO SIMULATED ACID RAIN
Authors: COX R. M.
Published: May 2006

Summary

Effects of simulated acid precipitation on pollination in Oenothera parviflora L. from different populations were examined both in vitro and in vivo. The responses of pollen to acidity (pH 5.6 to 2.6) in standing drop cultures and the stigma receptivity of flowers under field simulations of acid rain were observed. The response of pollen in vitro indicated significant inhibitory effects of pH, and demonstrated that pH values ≤ 3.6 were inhibitory to both germination and tube growth, when compared with the treatment of pH 5.6. Dosages of LD50 for in vitro pollen germination, taken as the initial pH of cultures for the different pollens, ranged from pH 3.49 to 3.72. Stigma receptivity assessed by germination and initial tube growth on the stigmatic surface also declined significantly (P < 0.01) in response to acid rain simulation prior to hand pollinations. Again simulants ≤ pH 3.6 significantly reduced stigma receptivity compared with the treatment at pH 5.6. Here LD 50, dosages, taken as the pH of the simulant, were pH 3.45 and 4.66 for the failure of potentially viable pollen to germinate, or produce tubes three times the length of the grain, respectively. These results are discussed in relation to rain chemistry in Southern Ontario, Canada.
SEED PROTEIN QUANTITIES OF FIELD‐GROWN SOYBEANS EXPOSED TO SIMULATED ACIDIC RAIN
Authors: EVANS LANCE S. , DIMITRIADIS LEANDROS , HINKLEY DEBORAH A.
Published: May 2006

Summary

Analysis of seeds harvested from field‐grown soybeans demonstrated that simulated acidic rainfalls from two experimental protocols can significantly decrease total protein contents of soybeans. Statistically significant differences in protein content per seed mass were obtained in three of four experiments at the field site. Mean protein contents of control plants for the three experiments reported herein were 33.0, 39.3 and 43.8 % and were comparable to protein yields obtained by commercial growers. When results were expressed as protein content per seed mass the changes were independent of reduction in seed mass per plant due to increased rainfall acidity. When results were expressed as protein contents per plant, decreases in protein of 20 % were common in plants exposed to rainfalls similar to ambient (pH 4.1) compared with experimental controls (pH 5.6).
PRODUCTION OF PROTONEMAL GEMMAE IN CULTURE BY THE MÓSS, DIDYMODON RECURVUS (GRIFF.) BROTH.
Authors: VASHISTHA B. D. , CHOPRA R. N.
Published: May 2006

Summary

Production of protonemal gemmae in Didymodon recurvus varies according to the conditions of culture. Low light and high temperature favour gemma formation, whereas high light and low temperature promote development of gametophytic buds on the protonema.
A POLLEN DIAGRAM FROM ST KILDA, OUTER HEBRIDES, SCOTLAND
Authors: WALKER M. J. C.
Published: May 2006

Summary

Pollen‐stratigraphic data supported by four radiocarbon dates are presented from a site on Hirta in the St Kilda archipelago, western Scotland. The pollen spectra in the basal sediments reflect an open tundra environment and are considered to be of Loch Lomond (Younger Dryas) Stadial age. Although no evidence of early Flandrian vegetation is preserved in the stratigraphy, the middle and upper levels of the profile contain a record of landscape changes throughout the middle and late Flandrian. During the period from about 6000 B.P. to the present, wood and scrub cover on the island was minimal and the vegetation consisted of a mosaic of grassland and heathland communities. Changes in the composition of the vegetation, involving in particular the role of maritime plant communities, are discussed principally in terms of regional climatic changes in the north‐west Atlantic province.
ROOT DEVELOPMENT IN THE SEAGRASS HALOPHILA OVALIS (R. BR.) HOOK F. (HYDROCHARITACEAE), WITH PARTICULAR REFERENCE TO ROOT LACUNAE
Authors: ROBERTS D. G. , McCOMB A. J. , KUO J.
Published: May 2006

Summary

The roots of Halophila ovalis are sheathed by root cap cells up to 2 mm above the meristem tip, and carry prominent root hairs. Air lacunae differentiate schizogenously close to the apex, where they are first occluded by material which stains heavily with toluidine blue, but some appear empty within 300 μ of the apex, offering a path for gaseous diffusion to the apical region. As a root matures the lacunae, which differentiate centripetally, contribute approx. 22 % of the root cross sectional area, as compared with about 65 % due to cortical cells.

Sieve tubes differentiate before xylem elements. Casparian strip formation and xylem differentiation are approximately synchronous, suggesting that these structures are involved in the uptake and transport of materials.
THE EFFECT OF SALINITY ON LEAF ULTRASTRUCTURE AND NET PHOTOSYNTHESIS OF TWO VARIETIES OF RICE: FURTHER EVIDENCE FOR A CELLULAR COMPONENT OF SALT‐RESISTANCE
Authors: FLOWERS T. J. , DUQUE E. , HAJIBAGHERI M. A. , McGONIGLE T. P. , YEO A. R.
Published: May 2006

Summary

The effects of sodium chloride on the leaf ultrastructure and net photosynthesis of two varieties of rice (Oryza sativa L.), the land race Amber and the elite breeding line IR2153.26.3.5.2, were examined. Similar concentrations of salt in the leaf tissue had a greater effect in bringing about a disorganization of cellular structure and of decreasing net photosynthesis in Amber than in IR2153.26.3.5.2. It is argued that these data support the view that rice varieties differ with respect to a cellular component of salt resistance.
STUDIES ON THE TOLERANCE TO SO2 OF GRASS POPULATIONS IN POLLUTED AREAS
Authors: WILSON G. B. , BELL J. N. B.
Published: May 2006

Summary

The development of acute and chronic sulphur dioxide (SO2) tolerance in lawn grass populations was studied by two approaches: the minimum time for tolerance to appear in Festuca rubra L., Lolium multiflorum Lam., L. perenne L., Phleum pratense L. and Poa pratensis L., was determined by comparison annually of plant samples from monoculture plots sown at a polluted site, with plants grown from the seed originally sown; the long term development of tolerance in F. rubra, D. glomerata L. and Agrostis tenuis Sibth. was also investigated by comparison of five lawns of different ages (1–c. 200 years) at a polluted site.

Tolerance to acute SO2 injury was detected in L. perenne and Phleum pratense only three and four years after sowing, respectively. However, population samples of these two species, collected from the field three years later, showed no significant SO2 tolerance. An analysis using morphological and isozyme variation as criteria showed that the tolerant population consisted of a large number of different individual genotypes. The populations experienced a state of evolutionary flux with rapid selection first of the tolerant, and subsequently of the non‐tolerant phenotypes. The disappearance of tolerance coincided with declining ambient SO2 concentrations.

The lawns of different ages were shown to represent an evolutionary series of increasing acute SO2 tolerance with age of lawn in F. rubra and A. tenuis. This demonstrated the continuing development of acute SO2 tolerance in grass populations over a prolonged period.

The significance of the occurrence and rate of development of SO2 tolerance for grasslands in polluted areas is discussed.
EFFECTS OF FREQUENCY AND DURATION OF SIMULATED ACIDIC RAINFALLS ON SOYBEAN YIELDS
Authors: EVANS LANCE S. , LEWIN KEITH F. , SANTUCCI KAREN A. , PATTI MITCHELL J.
Published: May 2006

Summary

An experiment to determine the effects of simulated acidic rain, applied at two frequencies and durations, on seed yields of two commercial cultivars of soybeans was performed during the summer of 1983. Plants were shielded from all ambient rainfalls automatically by two moveable exclusion covers and exposed to simulated rainfalls in quantities equal to the average amount of rainfall that occurs at the site during the growing season. Seed yields of soybeans (cv. Amsoy) exposed twice weekly to simulated rain of pH 41, 3.3 and 2.7 were, respectively, 0, 10 and 17 % below yields of plants exposed to simulated rain of pH 5.6. The linear treatment‐response function of seed yield versus rainfall pH for Amsoy was + 9.18 + 0.74x and had a correlation coefficient of 0.86 y is seed mass per plant and x is the pH of the simulated rain). The linear component of pH treatment differences showed a highly significant decrease in yield (P= 0.0034). For Amsoy plants exposed to simulated rainfalls daily, plants exposed to pH 4.1, 3.3 and 2.7 exhibited yields 10, 19 and 12%, respectively, below those exposed to simulated rainfalls of pH 56. A treatment‐response function (P= O.0713) of seed yield vs rainfall pH was y+ 7.35 + 0.56x and had a correlation coefficient of 0.84. Seed yields of the Williams cultivar were not affected by rainfall acidity. In both cultivars the daily, short duration rainfall regimen resulted in significantly lower yields compared with the twice weekly, longer duration rainfalls. The major portion of the differences in seed yield can be accounted for by the observed differences in number of pods per plant.
ULTRASTRUCTURAL AND HISTOCHEMICAL STUDIES OF TRANSFER CELLS IN THE CALLUS AND APOGAMOUS SPOROPHYTES OF PHYSCOMITRIUM COORGENSE BROTH.
Authors: LAL M. , NARANG A.
Published: May 2006

Summary

Ultrastructural and histochemical studies reveal that apogamous sporophytes develop spontaneously from gametophytic callus cells of Physcomitrium coorgense which have accumulated starch and developed wall ingrowths. Plasmodesmatal connections are retained between the apogamous outgrowths and the subtending callus. Although apogamous sporophytes lack a recognizable foot, the peripheral cells in the lower part of the seta develop wall ingrowths similar to those in the placental region in sporophytes of sexual origin.
INTERFERENCE BETWEEN HEALTHY AND RUSTED GROUNDSEL (SENECIO VULGARIS L.) WITHIN MIXED POPULATIONS OF DIFFERENT DENSITIES AND PROPORTIONS
Authors: PAUL N. D. , AYRES P. G.
Published: May 2006

Plants of groundsel (Senecio vulgaris L.), either inoculated with rust Puccinia lagenophorae Cooke or uninoculated, were grown to capitulum production at a range of densities up to 2240 plants m−2, both in monoculture and together in mixture. Rust infection reduced vegetative growth and capitulum production in monocultures and mixtures. However, in mixture, unequal interference between inoculated and uninoculated plants amplified the effect of rust infection on growth. The relative crowding coefficient of uninoculated over rusted groundsel consistently exceeded unity but showed no clear trend in response to planting density. Rust infection resulted in bimodal frequency distributions of plant height, particularly in mixture, i.e. many rusted plants were stunted and were confined to the lowest layers of the shoot canopy. Thus, the reduced yield of the inoculated component of mixtures resulted from the very severe inhibition of growth of a proportion of rusted plants. However, it appeared that suppressed, rusted plants remained able to respond to limitation of available resources since both dry weight partitioning to the roots and specific leaf area increased. Perhaps because of the ability of groundsel to adapt to unfavourable environmental conditions, rust infection resulted in little mortality. Thus, even heavily rusted suppressed plants were able to produce some capitula and, potentially, seed.
POLLEN CATCHMENT IN RELATION TO LOCAL VEGETATION: CEANN EAR, MONACH ISLES N.N.R., OUTER HEBRIDES
Authors: RANDALL R. E. , ANDREW R. , WEST R. G.
Published: May 2006

The relation between pollen deposition and phytosociology of 11 plant communities on the island of Ceann Ear, Monach Isles, has been studied. The relation of the phytosociology (frequency, Domin rating) of each community to the pollen analysis of a sample within it is described and the recognition of each community by its pollen spectrum is discussed. The representation of each pollen taxon in the pollen analyses in relation to the flora is tabulated, resulting in a classification of types of representation, from widespread to local to absent.

The minimum percentage of pollen of off‐island taxa is low (16%), over half being longdistance transport of Betula and Pinus. The frequency of off‐island pollen is considered in relation to the frequency of community and out‐community pollen, and various features of a plant community are suggested as possible factors in determining the relationship: height of vegetation, exposure, rate of local pollen deposition and the nature of the material trapping pollen.

The significance of the results for the interpretation of fossil pollen spectra with high non‐tree pollen frequencies (cold stages, post‐Mesolithic clearances) is considered in relation to the reflection of a mosaic of plant communities and of regional plant communities in the pollen rain, to long‐distance pollen transport and to grazing.
BIOLOGICAL EFFECTS OF A MERCURY FUNGICIDE ON A N2‐FIXING BLUE‐GREEN ALGA NOSTOC MUSCORUM: ISOLATION AND PRELIMINARY CHARACTERIZATION OF A Hg‐RESISTANT MUTANT
Authors: PRASAD A. B. , SAMANTA R. , VISHWAKARMA M. L. , VAISHAMPAYAN A.
Published: May 2006

Summary

Mercuric chloride, which is used as a fungicide in tropical paddy‐fields, inhibits growth (in N2, i.e. molecular nitrogen, and 5 mM KNO3 media) and heterocyst formation (in N8 medium) in the blue‐green alga Nostoc muscorum at a concentration of 0.3 μg ml−1and above. These inhibitory effects were reversed on supplementation with 3 mM exogenous glucose. A mercury resistant mutant of this alga has been obtained, which is stable through repeated cell transfers in N2 medium. It is suggested that a Hg‐inducible protein/enzyme system is responsible for the intracellular mercury‐resistance of this mutant.
15N DILUTION METHOD FOR ESTIMATING THE ABSORPTION OF ATMOSPHERIC NO2 BY PLANTS
Authors: OKANO K. , FUKUZAWA T. , TAZAKP T. , TOTSUKA T.
Published: May 2006

Summary

The 15N dilution method was used for the quantitative estimation of nitrogen dioxide (NO2) absorbed by Helianthus annuus and Zea mays during a relatively long period. The relationships between the amount of NO2 absorbed and the concentration of NO2 and length of exposure were investigated, in order to ascertain the reliability of this method.

The total amount of NO2‐nitrogen absorbed by the plants over two weeks (from two to four weeks after the sowing) increased with increasing concentrations of NO2. The rate of absorption of NO2 per unit leaf area also increased linearly with increasing concentrations of NO2 from 0 to 1 μl l−1. This means that the diffusive resistances of stomata or mesophyll tissues were not changed by the continuous exposure to NO2 at 1 μl l−1for two weeks. The absorption rate per unit leaf area in H. annuus was about three times greater than that in Z. mays.

The total amount of NO2‐nitrogen absorbed by the plants which were continuously exposed to 0.5 μl l −1NO2 rose not linearly but exponentially as the exposure time increased from zero to three weeks. This might in part have reflected the growth characteristics of the plants, since dry weight and leaf area increased exponentially during the period of exposure to the pollutant. The absorption rate per unit leaf area remained constant during the first two weeks, but thereafter increased significantly, probably due to the uptake of NO2‐nitrogen through the air‐soil‐root pathway.

These results demonstrated that the values estimated by the15N dilution method were reliable, and this method can be recommended for the quantitative determination of NO2 absorbed by plants during a long period.
THE MECHANISM OF ACTION OF CALCIUM IN THE INHIBITION OF HIGH TEMPERATURE‐INDUCED LEAKAGE OF BETACYANIN FROM BEET ROOT DISCS
Authors: COOKE A. , COOKSON A. , EARNSHAW M. J.
Published: May 2006

Summary

Effective inhibition of high temperature‐induced leakage of betacyanin from beet root discs occurs at concentrations of about 100 mM K+, Na+ or choline+, about 10 mM inorganic divalent cations in which Mn2+ Ca2+ Sr2+ Ba2+ Mg2+, and about 1 mM, Ln3+. Thermal protection is also afforded by a range of sugars and sugar alcohols suggesting that the action of monovalent cation salts, in particular, is at least partially due to an osmotic lowering of cell turgor pressure. Inorganic divalent cation specificity, as well as the ineffectiveness of the organic cations, decamethonium2+ and tris(ethylendiamine)cobaltic III, suggest that screening of membrane surface charge is not involved in decreasing betacyanin leakage. It is suggested that Ca2+, and other inorganic multivalent cations, act by binding to membrane components which may produce a decrease in membrane fluidity.
Do parties matter for local revenue policies? A comparison of Denmark and Norway
Authors: BLOM‐HANSEN JENS , MONKERUD LARS CHRISTIAN , SØRENSEN RUNE
Published: May 2006

Abstract. This article investigates the impact of party ideology on revenue politics. Theoretically, claims can be made that party ideology should matter for revenue policies. First, leftist governments are more favourable towards government intervention and a large public sector. To accomplish this, leftist governments need more revenue than bourgeois governments. Second, revenue policy is a redistributive policy area well suited for ideological positioning. However, the claim that party ideology does not matter can also be made since raising revenue is unpopular and politicians may shy away from new initiatives. Empirically, the question is unsettled. The article investigates the problem by looking at three revenue policy areas (income and property taxation, and user charges) in two countries (Denmark and Norway). The data used is from the municipal level, providing several hundreds of units to compare. The evidence favours the ‘parties matter’ argument, particularly in the Danish case.
The meaning and measure of state legitimacy: Results for 72 countries
Authors: GILLEY BRUCE
Published: May 2006

Abstract.  This article presents a quantitative measurement of the political legitimacy of states in the late 1990s and early 2000s for 72 states containing 5.1 billion people, or 83 per cent of the world's population. First, the concept of state legitimacy is defined and justified. The definition includes the subjects, objects and sub‐types of legitimacy. A strategy to achieve replicable cross‐national measurements of legitimacy is then outlined and implemented, including a discussion of data sources and three alternative aggregation methods. The results are briefly examined and tested, and the uncertainties of quantitative measures discussed. Finally, the role of supplementary qualitative measurement is considered.
Electroanatomic Characteristics of Atrial Premature Beats Triggering Atrial Fibrillation in Patients with Persistent Versus Paroxysmal Atrial Fibrillation
Authors: PAK HUI‐NAM , HWANG CHUN , LIM HONG EUY , KIM JIN WON , LEE HYUN SOO , KIM YOUNG‐HOON
Published: May 2006

Background: Although the electrical disconnection between the left atrium (LA) and pulmonary veins (PVs) by radiofrequency catheter ablation has been proven to be effective in controlling atrial fibrillation (AF), the recurrence rate is higher in patients with persistent AF (PeAF) than with paroxysmal AF (PAF). We hypothesized that the origin of the atrial premature beats (APBs) that trigger AF and the pattern of their breakthrough into the LA differ between PAF and PeAF.

Methods: We mapped 75 APBs (53 APBs triggering AF, 22 isolated APBs) from the LA and PVs in 26 patients with AF (age: 49.5 ± 9.6, males: 23, PAF = 17, PeAF = 9), using a noncontact endocardial mapping (NCM) system. The location of the preferential conduction (PC) sites and their conduction velocity (CV) were compared.

Results: In patients with PeAF, the earliest activation (EA) site and exit of the PC were more frequently located on the LA side of the LA–PV junction as compared with PAF (P < 0.001). Eighty‐one percent of the PCs were located in the area between the left and right superior PVs. The incidence of PCs was similar between the PeAF and PAF patients (P = NS). PCs were more commonly found with APBs inducing AF (63.3%) than with those not inducing AF (35.2%, P = 0.01). The CV of the PC was slower for PeAF than PAF (P < 0.001). The CV in the LA during sinus rhythm was also slower for PeAF than PAF (P < 0.01).

Conclusion: PeAF was more frequently triggered by APBs from the LA side of the LA–PV junction than PAF and resulted in slower conduction than did PAF. These findings may help explain the higher potential for recurrence after electrical PV isolation in patients with PeAF.
Experimental Model Simulating Right Ventricular Outflow Tract Tachycardia: A Novel Technique to Initiate RVOT‐VT
Authors: ZHOU JING , SCHERLAG BENJAMIN J. , YAMANASHI WILLIAM , WU RICHARD , HUANG YAN , LAZZARA RALPH , JACKMAN WARREN M. , PO SUNNY S.
Published: May 2006

Objective: To simulate right ventricular outflow tract tachycardia (RVOT‐VT) in experimental animals.

Background: The mechanism(s) whereby a discrete area of myocardium in the RVOT becomes arrhythmogenic remains unknown.

Methods: In 13 dogs, a circular catheter was placed in the proximal pulmonary artery (PA) to contact the endovascular circumference of the PA. A 50‐msec train of high‐frequency stimulation (HFS, 200 Hz), coupled to atrial pacing, was applied at each bipolar pair of the circular catheter. The coupling interval was adjusted so that the 50‐msec train occurred during the ventricular refractory period, that is, the QRS complex, in order to prevent stimulation of the myocardial sleeve within the proximal PA.

Results: In all dogs, HFS induced ventricular premature depolarizations and VTs with a left bundle branch block (LBBB) morphology and inferior axis (average 6.8 ± 1.6 V). Earliest activation was consistently recorded from the proximal PA. Esmolol, a short‐acting beta‐blocker (1 mg/kg), was administered intravenously in 11 dogs. The inducible ventricular ectopy was abolished in 10 dogs (>12 V, P < 0.05) and the response to HFS was blunted in one dog (10–11 V). After 30 minutes, the response to HFS returned to pre‐esmolol levels.

Conclusions: Stimulation of the sympathetic input to the proximal PA induces ventricular ectopy and VTs exhibiting a left bundle branch block morphology and inferior axis, closely simulating clinical RVOT‐VT. Beta‐blockade either abolishes or blunts this response, corroborating the sympathetic etiology in this model and in some clinical cases of RVOT tachycardias.
An Abnormal Right Ventricular Apical Angle is Indicative of Global Right Ventricular Impairment
Authors: López‐Candales Angel , Dohi Kaoru , Iliescu Anca , Peterson Ross C. , Edelman Kathy , Bazaz Raveen
Published: May 2006

The presence of right ventricular (RV) dysfunction is an adverse prognostic indicator but current echocardiographic methods have some limitations. RV apical angles in systole and diastole were correlated with known parameters of RV function in patients without pulmonary hypertension (Group 1) and in patients with pulmonary hypertension (Group 2). RV apical angles were significantly smaller in both systole (22 ± 7°) and diastole (33 ± 6°) in Group 1 patients when compared to Group 2 (54 ± 18°, p < 0.0001 and 59 ± 17°, p < 0.0001, respectively). RV apical angles, both in systole and diastole, were strongly correlated with RV end‐systolic area (R = 0.89, p < 0.0001) and end‐diastolic area (R = 0.81, p < 0.0001), respectively. Similarly, the apical systolic and diastolic angle correlated well with decreased tricuspid annular plane systolic excursion (TAPSE, R =−0.76 and R =−0.73, p < 0.001) as well as with decreased RV fractional area change (R =−0.81 and R =−0.77, p < 0.001). Therefore, we conclude that this new measurement of RV apical angle is simple and useful to quantify RV apical structural and functional abnormalities that are well correlated with global RV impairment in patients with chronic pulmonary hypertension.
Plantar warts in twins after successful bone marrow transplantation for severe combined immunodeficiency
Authors: Marini Alessandra , Niehues Tim , Stege Helger , Ruzicka Thomas , Hengge Ulrich R.
Published: May 2006

Nine‐year‐old twin sisters presented with long‐standing severe plantar warts following bone marrow transplantation for severe combined immunodeficiency (SCID). Combination therapy with keratolysis, cidofovir and water‐filtered infrared coagulation (WIRA) led to complete clearance after 8 months of therapy. This dermatologic problem and the treatment of SCID including gene therapy are discussed.
Assessment of the Impact of Sildenafil Citrate on Lower Urinary Tract Symptoms in Men with Erectile Dysfunction
Authors: Mulhall John P. , Guhring Patricia , Parker Marilyn , Hopps Carin
Published: May 2006

Introduction

Sildenafil citrate is an effective and well-tolerated oral erectogenic medication. Through phosphodiesterase type 5 (PDE5) inhibition, it induces relaxation in penile smooth muscle, resulting in erection. Due to its mild affinity for other PDE enzymes, it may cause smooth muscle relaxation in a number of other organs. Recent data suggest an association between erectile dysfunction (ED) and lower urinary tract symptoms (LUTS). Anecdotally some patients cite improvement in LUTS while using sildenafil.

Aim

This study was conducted to assess the impact of Viagra on LUTS, using the International Prostate Symptom Score (IPSS) questionnaire.

Main Outcome Measure

International Index of Erectile Function (IIEF) and IPSS inventories.

Methods

Men presenting to a sexual dysfunction clinic who were candidates and opted for treatment with sildenafil completed the IIEF and IPSS. Men with the IPSS scores greater than 10 were enrolled and completed the IPSS and IIEF questionnaires at least 3 months after the commencement of sildenafil. Comparisons were made between pre- and posttreatment scores in the IPSS and erectile function (EF) domain of the IIEF.

Results

Forty-eight men were enrolled, with a mean age of 62 ± 11 years. The mean improvement in the EF domain score was 7 points (P = 0.01). The mean improvement in the IPSS score was 4.6 points (P = 0.013) and in quality of life (QOL) score was 1.4 points (P = 0.025). In total, 60% of men improved their IPSS score, and 35% had at least a 4-point improvement in their score. The mean number of uses of sildenafil per week was 2.0 ± 0.6. No significant correlation was seen between the degree of the IPSS improvement and baseline IPSS, baseline EF domain score, or magnitude of improvement in EF domain score.

Conclusions

These data indicate a positive impact of Viagra on men with mild to moderate LUTS. It is presumed, although unproven, that the medication’s effect is mediated through bladder neck/prostatic smooth muscle relaxation.
ANDROTEST©: A Structured Interview for the Screening of Hypogonadism in Patients with Sexual Dysfunction
Authors: Corona Giovanni , Mannucci Edoardo , Petrone Luisa , Balercia Giancarlo , Fisher Alessandra D. , Chiarini Valerio , Forti Gianni , Maggi Mario
Published: May 2006

Introduction

Detecting hypogonadism, which is important in the general population, becomes crucial in patients with sexual dysfunctions, because hypogonadism can have a causal role for them and testosterone (T) substitution represents a milestone for the therapy.

Aim

No inventories are available for the screening of hypogonadism in patients with sexual dysfunction. We wished to set up a brief structured interview providing scores useful for detecting hypogonadism defined as low total T (<10.4 nmol/L, 300 ng/dL) in a symptomatic population (sexual dysfunction).

Methods

A minimum set of items was identified within a larger structured interview through iterative receiver-operating characteristic curve analysis, with assessment of sensitivity and specificity for hypogonadism in a sample of 215 patients.

Main Outcome Measures

Sensitivity and specificity were verified in a further sample of 664 patients. Correlation of test scores with prostate-specific antigen (PSA), testis volume, and others clinical and psychological parameters, was assessed for concurrent validity.

Results

In the validation sample, the final 12-item version of the interview (ANDROTEST ©) had a sensitivity and specificity of 68% and 65%, in detecting low total T (<10.4 nmol/L) and of 71% and 65%, in the screening for low free T (<37 pmol/L). Furthermore, patients with a pathological test (i.e., score >8) showed higher prevalence of hypogonadism-related signs, such as lower testis volume and higher depressive symptoms. Finally, when only younger patients (<54 years, which represents the median age of the sample) were considered, Log10 [PSA] levels were significantly lower in those with ANDROTEST © score >8.

Conclusion

ANDROTEST © is a quick and easy-to-administer interview that provides scores for the screening of male hypogonadism in patients with sexual dysfunction.
Prescriptive patterns of nurse practitioners and physicians
Authors: Running Alice , Kipp Catherine , Mercer Victoria
Published: May 2006

Purpose: To compare the prescriptive patterns of nurse practitioners (NPs) and physicians in a primary care setting for the treatment of sinusitis, bronchitis, musculoskeletal injury, and back pain.

Data sources: One hundred charts were reviewed for each condition for a total of 400 charts (200 of the charts were for NP providers, and 200 were for physician providers).

Conclusions: While the mean scores of the differences in prescriptive patterns were found to be statistically significant in only one instance, the overall findings indicate slight differences in the administration of medications for patients. Additionally, NPs prescribed more over‐the‐counter medications and provided more nonpharmacotherapeutic interventions for their patients than the physicians.

Implications for practice: The results, although statistically significant in only one category, indicate that NPs may be more cautious in their prescriptive interventions and provide more teaching for patients.
Comparison of the traits of physically active and inactive women
Authors: Purath Janet
Published: May 2006

Purpose: To explore the determinants of physical activity for working women and to compare traits of active with inactive women.

Data sources: Original research articles, books, government reports, and self‐report survey data from 373 university employees who attended an employer‐sponsored health screening.

Conclusions: Active women had lower body mass indexes and more beneficial high‐density lipoprotein cholesterol when compared to inactive women. They were more likely to have a past history of sustained physical activity. Significant psychosocial determinants to physical activity included time constraints, confidence in finding an activity that can be enjoyed in bad weather, and not being too tired at the end of the day to engage in physical activity.

Implications for practice: Nurse practitioners are in key positions to help women increase their levels of physical activity. Knowing the traits of active women can help busy clinicians focus interventions that address those traits, leading to greater efficiency and effectiveness.
Management of chronic hepatitis B virus infection: Current perspectives for the nurse practitioner
Authors: Perrillo Robert
Published: May 2006

Purpose: To address the clinical management of chronic hepatitis B virus (HBV) infection.

Data sources: Studies from the National Library of Medicine that examine the natural history, prevention, and antiviral therapy of chronic HBV infection, with emphasis on recent studies.

Conclusions: Chronic infection with HBV is a frequent cause of cirrhosis, liver cancer, and liver‐related mortality worldwide. Strategies to prevent infection, screen for liver cancer in HBV carriers, and treat chronic hepatitis B are all important in managing this disorder.

Implications for practice: Much can be done to prevent and treat infection. Both classes of drugs to treat hepatitis B, nucleoside analogues and interferons, have advantages and disadvantages. Selection of therapy should be based on biochemical, histological, and virological parameters as well as consideration of several practical issues.
Fecal Bacterial Diversity in a Wild Gorilla
Authors: Frey Julie C. , Rothman Jessica M. , Pell Alice N. , Nizeyi John Bosco , Cranfield Michael R. , Angert Esther R.
Published: May 2006

We describe the bacterial diversity in fecal samples of a wild gorilla by use of a 16S rRNA gene clone library and terminal-restriction fragment length polymorphism (T-RFLP). Clones were classified as
Firmicutes
,
Verrucomicrobia
,
Actinobacteria
,
Lentisphaerae
,
Bacteroidetes
,
Spirochetes
, and
Planctomycetes
. Our data suggest that fecal populations did not change temporally, as determined by T-RFLP.