bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative measurements of gas‐exchange, acid accumulation and chlorophyllafluorescence of different species ofClusiashowing C3photosynthesis, or crassulacean acid metabolism, at the same field site in Venezuela
Authors: HAAG‐KERWER A. , GRAMS T. E. E. , OLIVARES E. , BALL E. , ARNDT S. , POPP M. , MEDINA E. , LÜTTGE U. 
Published: April 2006

summaryFour differentClusiaspecies showing C3photosynthesis (C. multiflora) or crassulacean acid metabolism (CAM) (C. rosea, an unidentifiedClusiasp. andC. alata)co‐occur in the same habitat in the northwest of Venezuela. The aim of this field study was to correlate the adaptive changes in chlorophyll a fluorescence with gas exchange patterns and deacidification of nocturnally accumulated organic acids.The results indicate that inC. roseaandClusiasp. a lowering of the potential quantum yield, measured as Fv/Fmafter 10 min of dark adaptation, is restricted to the early morning hours. With the onset of deacidification there was no further decline in Fv/Fm, although the irradiance upon the leaves remained high. For the C3‐plant,C. multiflora, changes in Fv/Fmwere correlated with changes in irradiance incident on the leaves before predarkening for 10 min for Fv/Fmmeasurements. The fast relaxation of Fv/Fmunder low light indicates thatC. multiflorawas not suffering photoinhibitory damage. Effective quantum yield as determined by ΔF/Fm, was low under high irradiances forC. roseaandClusiasp. and did not change significantly forC. roseaduring phase III of CAM. During the time of low incident irradianceC. alataandC. multiflorareached an effective quantum yield that was close to the optimal quantum yield of electron transport. It is noteworthy that apparent electron transport rates through photosystem II (PS II) (ΔF/F'm) × PPFD) were highest forC. rosea, Clusiasp. andC. alataduring phase III of CAM. Electron transport rates inC. multiflorawere lower under high irradiance and did not differ from those found in phases II and IV of CAM. The possible role of CO2, evolution from acid decarboxylation with respect to photosynthetic efficiency is discussed.
Rise and demise of cold‐climatePicea abiesforest in Sweden
Authors: KULLMAN LEIF 
Published: April 2006

summaryThe study focuses on structural and compositional dynamics of high‐elevation (boreal) mixedPicea‐Betulaforest in the Swedish Scandes. Data from seven years' monitoring of crown condition (defoliation), seed viability, soil and air temperatures, a tree‐ring chronology and the age structure ofPiceaare presented. Real long‐term dynamism of the tree cover was inferred from radiocarbon dates of buried subfossil wood. At all time‐scales, the forest has responded sensitively to thermal variability.Piceaseed viability, demography and radial growth correlated positively with summer temperature. The currentPiceapopulation largely results from warming during the first half of the 20th century. However, cooler climate in the pastc.five decades has led to reduced population and radial growth as well as accelerating crown defoliation. This decline is related primarily to winter soil temperatures. The mechanism of needle loss is deduced to be winter desiccation and resulting cavitation of the xylem. It is hypothesized that previous similar episodes have been balanced by periods of spruce expansion. The successional history leading up to the present stage includes fire disturbance and subsequent cooling during the Little Ice Age, which prolonged and consolidated the early post‐fireBetulaphase.Pinuswas incapable of penetrating these unusually dense birch stands, whereas the shade‐intolerant spruce could establish progressively as climate warmed. This course of structural and compositional dynamism relates to complex interactions of disturbance, climate change and reproductive responses.
The effect of ozone fumigation over one season on photosynthetic processes of Quercus robur seedlings
Authors: FARAGE P. K. 
Published: April 2006

summary Quercus robur saplings were exposed to elevated O3 (80 nmol mol‐1) in hemispherical glasshouses for one growing season in order to assess the effects of this pollutant on photosynthesis. Measurements of chlorophyll fluorescence induction kinetics in mid‐summer showed that plants exposed to both control O3 (20 nmol mol−1) and elevated O3 treatments experienced significant photoinhibition of photosynthesis. Elevated O3 increased photoinhibition. At the end of the summer, photosynthetic CO2 uptake, measured at either light saturation or under light‐limiting conditions, was not significantly different between plants from the two O3 treatments. Although the maximum rate of carboxylation velocity, as estimated from the response of CO2 uptake to intercellular CO2 concentration, the maximum quantum efficiency and the maximum rate of electron transport measured in vivo were decreased by O3 exposure, the responses differed between plants and, overall, the decreases were not statistically significant. The results suggest that O3 levels that are at present reached for a few days during photochemical episodes in the summer are not sufficient to cause measurable lasting damage to photosynthetic CO2 uptake in oak saplings assessed over one growing season.
The effects of fertilizer and root competition on seedlings of Orchis morio and Dactylorhiza fuchsii in chalk and clay soil
Authors: MCKENDRICK S. L. 
Published: April 2006

summaryThe responses of two native British orchids, Orchis morio L. and Dactylorhiza fuchsii (Druce) Soó, to fertilizer and root competition were tested in pots of natural soil. Seedlings were raised from seed in symbiotic culture, set into pots of natural soil and grown for 10 wk in a controlled environment chamber with and without the grass Festuca rubra L. on clay, chalk and fertilized chalk soil. The growth of O. morio was not significantly affected by fertilization. Fertilization of D. fuchsii produced a marked reduction in growth, particularly of the roots. Root competition had little effect on either of the orchids, except that plants of O. morio grown with F. rubra had a greater allocation to thicker, tuber‐bearing roots relative to fine roots (c. 1 mm diameter or less) compared with those grown without grass. These results were in marked contrast to those obtained for the typical grassland perennial Leontodon hispidus L., in which fertilization led to a very large increase in growth, and root competition greatly reduced growth.
The effects of shade on seedlings of Orchis morio and Dactylorhiza fuchsii in chalk and clay soil
Authors: MCKENDRICK S. L. 
Published: April 2006

summaryThe responses of two native British orchids, Orchis morio L. and Dactylorhiza fuchsii (Druce) Soó, to shading were tested using 7‐ and 8‐month‐old symbiotically propagated seedlings. Seedlings were raised in culture, set into tubes of clay and chalk soil and grown under shade screens for 10‐wk in a controlled environment chamber in deep green shade, green shade, neutral shade, and unshaded (photosynthetic photon fluence rates (PPFR) 24, 54, 54 and 225 μmol m−2s−1respectively). The dicotyledonous perennial Leontodon hispidus L. was also tested for comparison. The orchids tolerated shade more than did L. hispidus, in which a decrease in PPFR led to a decrease in d.wt, an increase in specific lead area (SLA) and elongation of the petioles. In O. morio, lower PPFR led to only a slight decrease in d.wt in the most shaded treatment, an increase in SLA similar to that of L. hispidus, and an increase in the vertical inclination of some leaves. In D. fuchsii lower PPFR led to a reduction in d.wt, mainly in the roots at higher, and in the leaves at lower, photon irradiance. A change from neutral to green shade reduced growth in L. hispidus, but had no effect on either orchid. The physiological and ecological implications of shade tolerance in orchid seedlings are discussed.
Manipulating secondary metabolism in cultured plant cells
Authors: YEOMAN M. M. , YEOMAN C. L. 
Published: April 2006

summaryThis review attempts to present an overall strategy for the production of useful secondary metabolites by cultured plant cells. After consideration of the nature and utility of secondary metabolites and the possible role of these substances to the plant, the review focuses attention on the properties of the plant cells in culture and how the cell populations and their physical and chemical environment can be manipulated to encourage the synthesis and accumulation of secondary products. Finally, consideration is given to the involvement of genetic engineering in the production of cells to perform particular metabolic tasks and how these techniques might contribute to the development of a new strategy to enable the production of useful secondary metabolites on a commercial scale.

CONTENTS

Summary
553

I.
Introduction
553

II.
Development of a strategy
555

III.
Concluding remarks
565

Acknowledgements
565

References
565
A bean epicuticular glycoprotein is present in the extracellular matrices around infection structures of the anthracnose fungus, Colletotrichum lindemuthianum
Authors: HUTCHISON KATIE A. , O'CONNELL RICHARD J. , PAIN NAOMI A. , GREEN JONATHAN R. 
Published: April 2006

summaryMonoclonal antibodies were raised to Colletotrichum lindemuthianum (Sacc. & Magn.) Briosi & Cav. infection structures which had been isolated from leaves of Phaseolus vulgaris L. by isopycnic centrifugation and immunomagnetic separation. One of the antibodies, UB29, recognized a carbohydrate epitope in a 200 kDa glycoprotein present on the surface of conidia, germ‐tubes and appressoria when they developed on host tissue. Intracellular hyphae were not labelled. Immunogold labelling showed that the antigen was confined to the extracellular matrices around such structures. No such antigen was detected by immunofluorescence or Western blotting when the fungus developed in vitro. UB29 recognized a glycoprotein of identical Mr located in the epicuticular wax layer of uninoculated bean hypocotyls. The results suggest that a host epicuticular glycoprotein is present in the extracellular matrices of fungal structures during growth on the plant surface.
Mass and energy exchange between the atmosphere and leaf influence gas pressurization in aquatic plants
Authors: STEINBERG S. L. 
Published: April 2006

summaryA mechanistic model was used to describe how mass and energy exchange between a leaf and air affect internal pressurization in aquatic plants. The core of the model is the calculation of the temperature of a leaf for which the energy balance is zero. The leaf temperature and water vapour gradient between leaf and air are then used to calculate potential pressurization. Simulations with the model were used to demonstrate the sensitivity of gas pressurization in aquatic plants to key environmental and physiological factors including radiation, temperature, humidity, wind speed, leaf size and leaf conductance. The model confirms other published data showing that humidity‐induced pressurization is the dominant mode of pressurization under most conditions. The simulations also demonstrated that thermal transpiration and humidity‐induced pressurization are not separate phenomena, but are dependent on the energy balance of the leaf, which in turn is affected by complex interactions between the leaf and environment.
Prediction of the growth response to elevated CO2: a search for physiological criteria in closely related grass species
Authors: ROUMET C. , ROY J. 
Published: April 2006

summaryUsing 11 closely related grass species, we tested the capacity of physiological criteria to predict the growth response to elevated CO2 and to categorize the species with regard to their CO2 response. A growth analysis was conducted under productive conditions both at ambient (350 μmol mol−1) and elevated (700 μmol mol−1) CO2. The relative growth rate stimulation was regressed against each of the growth rate components measured at ambient CO2.Growth response to CO2 was positively correlated with specific leaf area (sla, the leaf surface area per unit of leaf weight), leaf area ratio (the leaf area per unit of total plant dry weight) and negatively correlated with net assimilation rate and leaf nitrogen concentration, both per unit of leaf area. We suggest that sla has a predominant role in these relationships. Different hypotheses are proposed and discussed in order to explain why species with low sla are less responsive to elevated CO2. Neither biomass allocation, relative growth rate, shoot or root specific activities per unit of mass, nor chemical composition were significantly correlated with growth response to CO2.The four predictive criteria mentioned above coherently differentiate the five wild annual species (higher sla, stronger growth response to CO2) from the four wild perennials. The two perennial crop species, with the highest sla, were more responsive than the wild species.
Cytogenetic evidence for autopolyploidy in Parnassia palustris
Authors: WENTWORTH J. E. , GORNALL R. J. 
Published: April 2006

summaryDiploid populations of Parnassia palustris L. var. palustris and var. condensata Travis & Wheldon have a highly symmetrical karyotype, consisting of seven metacentrk and two submetacentric chromosomes. The gross morphology of the karyotype of tetraploid populations is indistinguishable from that of the diploids. Studies of meiosis in tetraploids of both varieties demonstrated a high frequency of quadrivalent formation, strongly suggesting an autopolyploid origin. Later stages of meiosis in the tetraploids are regular and the pollen shows no decrease in stainability compared with that of the diploids. Some evidence is presented to show that tetraploids of both varieties may have a wider ecological amplitude than do diploids.
Inoculum potential of ericoid endophytes of Western Australian heaths (Epacridaceae)
Authors: HUTTON B. J. , DIXON K. W. , SIVASITHAMPARAM K. , PATE J. S. 
Published: April 2006

summaryThe nature and location of infective inocula of ericoid endophytes were examined in habitat soil sampled dry during midsummer from different depths down the rooting profile of an Epacridaceae‐rich mediterranean‐type ecosystem in south‐western Australia. Efficacy of soil inocula was tested using aseptically germinated seedlings ofLysinema ciliatumR. Br. grown in a glasshouse. Hair roots, the principal structures colonized by endophytes, constituted c. 70% of the total length of root systems formed under glasshouse culture. Colonization of these hair roots by endophytes was greatest (17%) when seedlings had been inoculated with habitat soil from the upper 24 cm zone and declined to less than 1% following inoculation with soil obtained from a depth of 36 cm and beyond. By contrast, sampling of a naturally growing epacrid (Leucopogon conostephioidesD.C.) at the same study site during the wet midwinter growing season showed uniformly high (34–43 %) infection of hair roots down to maximum rooting depth at 70 cm. The infectivity of sieved soil fractions from bulk habitat soil was considerably greater (mean of 17 % hair root infection) for glasshouse‐culturedLysinema ciliatuminoculated with the 251–305 μm particle size fraction than for that inoculated with coarser (306–5000 μm) and finer (39–250 μm) sieve fractions (0–6% infection). Dilution of bulk soil with sterilized soil indicated maximum infection at 1:16 dilution, declining to negligible infectivity at a dilution of 1:100. The data support the hypothesis that inoculum persists through summer principally in relatively coarse fractions of organic matter near the soil surface. With the onset of autumn rains, downward mycelial growth emanating from this upper zone rapidly recolonizes the soil profile and eventually promotes extensive colonization of hair roots produced that season by the epacrid root system.
Physiological heterogeneity within fungal mycelia: an important concept for a functional understanding of the ectomycorrhizal symbiosis
Authors: CAIRNEY J. W. G. , BURKE R. M. 
Published: April 2006

summaryIndividual mycelia of filamentous fungi display considerable heterogeneity at the physiological level. Important physiological processes such as nutrient absorption, extracellular enzyme secretion and solute translocation occur differentially within an individual mycelium, and vary according to spatio‐temporal changes in patterns of gene expression as the mycelium develops and senesces. In ectomycorrhizal (ECM) fungi, gene expression appears to be strongly influenced by interaction with the soil environment and the host root. The ECM mycelium is thus a complex and dynamic entity wherein discrete regions display particular physiological attributes. Physiological heterogeneity is important in the overall functioning of the symbiosis. In the particular case of movement of phosphorus from soil to host root in the ECM symbiosis, heterogeneity might provide the driving force for the integrated processes of absorption, translocation and transfer. It is suggested that it is only by considering the sum of the seemingly disparate physiological processes within the heterogeneous mycelium that mycorrhizal functioning can be fully understood.
A conceptual model for the development of Phytophthora disease in Quercus robur
Authors: Jönsson U. 
Published: April 2006

SummaryHere, a conceptual model is presented for the development of Phytophthora disease in pedunculate oak. The model is presented using the causal loop diagram tool and gives an overview of how various abiotic and biotic factors, such as soil moisture, nutrient availability and mycorrhizal colonization, may affect the reproduction and the infective capacity of soil‐borne Phytophthora species, the susceptibility of the host and subsequent disease development. It is suggested that the link between the root damage caused by Phytophthora species and overall tree vitality is in the assimilation and allocation of carbon within the plants. The potential impact of environmental factors on these processes is discussed. The model is presented with reference to scenarios related to variation in soil moisture and nutrient availability. The need for species‐specific validation of the model and the implications of the model are discussed.
Immunocytochemical localization of 3‐methylcrotonyl‐CoA carboxylase in cultured ependymal, microglial and oligodendroglial cells
Authors: Murín Radovan , Verleysdonk Stephan , Rapp Mirna , Hamprecht Bernd 
Published: April 2006

AbstractTo evaluate the ability of ependymal, microglial and oligodendroglial cells to degrade leucine, the presence of 3‐methylcrotonyl‐CoA carboxylase (MCC) was investigated in cultures of these cells. MCC is a biotin‐containing heterodimeric enzyme that is specific for the irreversible part of the leucine catabolic pathway. It has been reported previously that in cell culture MCC is expressed in astrocytes and a subpopulation of neurones. In the present study ependymal, microglial and oligodendroglial cell cultures, derived from the brains of newborn rats, were examined for the expression of MCC by RT–PCR, western blotting and immunocytochemistry. The results of RT–PCR and western blotting showed the presence of mRNA as well as protein of both subunits of MCC in ependymal, microglial and oligodendroglial cell cultures. Immunocytochemical investigation of the cellular and subcellular distribution of MCC demonstrated a mitochondrial location of MCC in all neuroglial cell types investigated. The ubiquitous expression of MCC in glial cells demonstrates the ability of the cells to engage in the catabolism of leucine transported into the brain, mainly for the generation of energy.
Substance P release evoked by capsaicin or potassium from rat cultured dorsal root ganglion neurons is conversely modulated with bradykinin
Authors: Tang He‐Bin , Inoue Atsuko , Iwasa Mikiko , Hide Izumi , Nakata Yoshihiro 
Published: April 2006

AbstractTo clarify the molecular mechanism of substance P (SP) release from dorsal root ganglion (DRG) neurons, we investigated the involvement of several intracellular effectors in the regulation of SP release evoked by capsaicin, potassium or/and bradykinin. Bradykinin‐evoked SP release from cultured adult rat DRG neurons was attenuated by either the mitogen‐activated protein kinase kinase (MEK) inhibitor (U0126) or cycloheximide. As the long‐term exposure of DRG neurons to bradykinin (3 h) resulted in extracellular signal‐regulated kinase (ERK) phosphorylation at an early stage and thereafter induced cyclooxygenase‐2 (COX‐2) protein expression, which both contribute to the SP release triggered by bradykinin B2 receptor. The long‐term exposure of DRG neurons to bradykinin enhanced the SP release by capsaicin, but attenuated that by potassium. Interestingly, the inositol 1,4,5‐triphosphate (IP3)‐induced calcium release blocker [2‐aminoethyl diphenylborinate (2‐APB)] not only inhibited the potassium‐evoked SP release, but also completely abolished the enhancement of capsaicin‐induced SP release by bradykinin from cultured DRG neurons. Together, these findings suggest that the molecular mechanisms of SP release by bradykinin involve the activation of MEK, and also require the de novo protein synthesis of COX‐2 in DRG neurons. The IP3‐dependent calcium release could be involved in the processes of the regulation by bradykinin of capsaicin‐triggered SP release.
Investigating the factors influencing professional identity of first‐year health and social care students
Authors: Adams Kim , Hean Sarah , Sturgis Patrick , Clark Jill Macleod 
Published: April 2006

AbstractInterprofessional education (IPE) involves students from different professions being brought together to learn about each other's profession. Several models of IPE exist, and central to the debate around which of these models is the most appropriate is the question of the stage of training in which to implement these programmes. Currently, however, there is no consensus on this question. Debate so far has revolved around the strength of professional identities, or lack thereof, amongst pre‐qualifying students and how this may influence interprofessional learning. The potential role of professional identity in IPE seems to be unresolved. The present article adds to this debate by investigating the level of professional identity when students commence their professional studies; the differences in the level of professional identity between students from a range of professions; and the factors which may affect the initial levels of professional identification. Data were collected by questionnaire from the first‐year cohort of Health and Social Care (H&SC) students embarking on IPE as an embedded part of an undergraduate pre‐qualifying programme. A sample of 1254 students was achieved. Professional identity was measured using an adaptation of a previously described scale. Our findings suggest that a degree of professional identity is evident before students begin their training. Differences in strength of initial professional identity were observed across professions, with physiotherapy students displaying the highest levels of professional identification. To test for associations between professional identity and a number of independent variables, an ordinary least squares (OLS) regression model was estimated. The variables that were found to be significant predictors of baseline professional identity were: gender; profession; previous work experience in H&SC environments; understanding of team working; knowledge of profession; and cognitive flexibility. Some explanations for these findings are presented and the implications are discussed.
Reviewing experience and testimony as pedagogical resources in open learning
Authors: Shakespeare Pam 
Published: April 2006

AbstractAccounts of experience and direct testimony are used extensively in health and social care education. In the sphere of open and distance learning (ODL) they both offer a richness and texture in the materials and form the focus for the use of a spectrum of ‘human data’, which are central to the health and social care professions. This article discusses some of the uses of experience and testimony in ODL relating to health and social care and examines ways in which testimony is transformed for pedagogic purposes in open and distance learning.