bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of ambient ozone on injury and yield of Phaseolus vulgaris at four rural sites in the Netherlands as assessed by using ethylenediurea (EDU)
Authors: TONNEIJCK A. E. G. , VAN DIJK C. J. 
Published: March 2003

SUMMARYTo assess adverse effects of ambient ozone on injury and yield, EDU (ethylenediurea) and non‐EDU‐treated plants of bean (Phaseolus vulgaris L. cv. Lit) were exposed to ambient air at four rural sites in the Netherlands in 1994. After 6 wk of exposure, the proportion of leaves injured in non‐EDU‐treated plants was higher than that in plants treated with the antioxidant. A maximal degree of 35 % injury was observed. The highest ozone levels accumulated at each site for three consecutive days before injury clearly exceeded the proposed short‐term critical level for injury development. Both injury in untreated plants and the protective effect of EDU differed between sites and were not related to the measured ozone levels. EDU increased the d. wt of dry (mature) pods after 11 wk of exposure but not of green (marketable) pods after 6 wk. The effect of EDU in enhancing dry pod yield did not differ between sites and was 20% on average. The proportional yield increases in EDU‐treated plants compared with those of non‐EDU‐treated plants at the sites were not correlated with the measured ozone levels known to adversely affect bean yield. The available evidence, however, suggests that ambient ozone was involved in the observed yield increase by EDU. When the dry pods were harvested, EDU‐treated plants had more leaves than non‐EDU‐treated ones. The effect of EDU in delaying senescence appears to be an important factor to consider when attempting to evaluate the effect of ambient ozone on pod weight in beans using the EDU approach.
Effects of soil compaction on plant growth phosphorus uptake and morphological characteristics of vesicular—arbuscular mycorrhizal colonization of Trifolium subterraneum
Authors: NADIAN H. , SMITH S. E. , ALSTON A. M. , MURRAY R. S. 
Published: March 2003

SUMMARYWe investigated the effect of soil compaction and phosphorus (P) application on morphological characteristics of mycorrhizal colonization and growth responses, to determine the reasons for reduced responses observed in our previous work with compacted soil. Growth, phosphorus (P) uptake and intensity of vesicular–arbuscular (VA) mycorrhizal colonization were studied in clover plants (Trifolium subterraneum L.) with and without VA mycorrhizal colonization at two P applications and three levels of soil compaction. Phosphorus was supplied either at constant mass concentration (mg P kg−1 soil) or at constant volume concentration (mg P dm−3 soil). Increasing bulk density of the soil from 1·1 to 1.6 Mg m−3 significantly decreased root length and shoot d. wt, but increased the diameter of both main axes and first order lateral roots regardless of P application. Total P uptake and shoot d. wt of clover plants colonized by Glomus intraradices (Schenck & Smith) were significantly greater than those of non‐mycorrhizal plants at all levels of soil compaction and both P applications. However, soil compaction to a bulk density of 1.6 Mg m−3 (penetrometer resistance = 3.5 MPa at a matric potential of − 33 kPa) significantly decreased mycorrhizal growth response. There was no evidence that the increased volume concentration of P at high bulk densities was responsible for the reduced responses. Soil compaction had no significant effect on the fraction of root length containing arbuscules and vesicles, but total root length colonized by arbuscules, vesicles or by any combination of arbuscules, vesicles and intra‐radical hyphae significantly decreased as soil compaction was increased. The air‐filled porosity of highly compacted soil, which varied from 0.07 to 0.11 over the range of matric potentials encountered (− 33 and − 100 kPa), had no significant effect on the intensity of internal colonization.
Topological scaling and plant root system architecture: developmental and functional hierarchies
Authors: BERNTSON GLENN M. 
Published: March 2003

SUMMARYTopology is an important component of the architecture of whole root systems. Unfortunately, most commonly applied indices used for characterizing topology are poorly correlated with one another and thus reflect different aspects of topology. In order to understand better how different methods of characterizing topology vary, this paper presents an exploration of several different methods for assigning order within branched root systems on the basis of (a) developmental (centrifugal) vs. functional (centripetal) ordering sequences and (b) whether orders are assigned to individual links or groups of adjacent links (segments). For each ordering system, patterns of scaling in relation to various aspects of link and segment size are explored using regression analyses. Segment‐based ordering systems resulted in better fits for simple scaling relationships with size, but these patterns varied between developmental vs. functional ordering as well as the different size metrics examined. The functional (centripetal), link‐based ordering system showed complex, non‐linear scaling in relation to numbers of links per order. Using a simple simulation model of root growth, it is demonstrated that this method of characterizing root topology in relation to root size might be a more powerful tool for characterizing root system architecture than in the use of simple, single‐index characterizations of topology.
Effects of ozone and drought stress on the physiology and growth of two clones of Norway spruce (Picea abies)
Authors: KARLSSON P. E. , MEDIN E. L. , WALLIN G. , SELLDÉN G. , SKÄRBY L. 
Published: March 2003

SUMMARYCuttings of two clones of Norway spruce,Picea abies(L.) Karst., were exposed to three different ozone concentrations in open‐top chambers during four months in the summer of 1990. The treatments were charcoal‐filtered air, non‐filtered air and non‐filtered air with extra ozone(c.30 ppb) added daily between 1100–1800 local time. During the last 4 wk of the exposure period, half the seedlings were drought‐stressed, while the remainder were well watered. Biomass, gas exchange and water potential were measured during the drought stress period. The ozone treatments affected the two clones very differently. High ozone reduced the rate of biomass increase in the faster‐growing clone (clone M) whereas ozone generally stimulated the rate of biomass increase in the slower‐growing clone (clone L). At the end of the measuring period, the high‐ozone treatments reduced the rate of root biomass increase of the well watered seedlings of the M‐clone, but it had no effect on the drought‐stressed seedlings of the same clone, probably because the root growth was already to a large extent inhibited by the drought stress.The treatment with the highest concentration of ozone partly protected the seedlings of the M clone against the drought stress, presumably by delaying shoot growth and thus delaying the increase in the total transpiring needle area. As a result, stomata tended to close less during the drought period in this treatment.The results are discussed in relation to the suggested critical level for ozone effects on trees.
Inter‐ and intraspecific variation in the ITS region of rDNA of ectomycorrhizal fungi in Fennoscandia as detected by endonuclease analysis
Authors: KÅRÉN OLA , HÖGBERG NILS , DAHLBERG ANDERS , JONSSON LENA , NYLUND JAN‐ERIK 
Published: March 2003

SUMMARYInterspecific and intraspecific variation in the internal transcribed spacer (ITS) region of rDNA of ectomycorrhizal fungi of 44 species in 17 genera were examined using the restriction fragment length polymorphism (RFLP) method. For each species, two to five herbarium vouchers (mainly basidiocarps), collected throughout Fennoscandia, were examined. The ITS region was amplified using the polymerase chain reaction (PCR) and the universal primers ITS1 and ITS4, and subjected to RFLP analysis with three endonucleases. Intraspecific polymorphisms in the ITS region were found in seven species (in nine of the 132 herbarium vouchers). Polymorphisms were due to length mutations, ranging from 5 to 15 bp in four of the seven polymorphic species and mutations in endonuclease restriction sites in six species, mostly affecting only one endonuclease, but in two species two endonucleases. Using a single endonuclease, a unique RFLP pattern could be obtained for more than half the investigated species. By combining different endonucleases, 34 (77%) of the species could be distinguished from another. The remaining RFLP types occurred in one genus. On the basis of the low intra‐ but high interspecific variation in the ITS region, it is concluded that most ectomycorrhizas formed by the 44 investigated species should be recognized by comparison with this dataset, if the mycorrhizas are sampled from a site located in Fennoscandia. However, in datasets from even larger geographical areas encompassing a higher degree of intraspecific variation in the ITS region, or when mycorrhizas from several sites distant from each other are compared, it might be necessary to include local reference species.
Changes in shikimate dehydrogenase and the end products of the shikimate pathway, chlorogenic acid and lignins, during the early development of seedlings of Capsicum annuum
Authors: DÍAZ JOSÉ , BARCELÓ A. ROS , DE CÁCERES F. MERINO 
Published: March 2003

SUMMARYThe developmental regulation and organ‐specific expression of shikimate dehydrogenase was studied in seedlings of Capsicum annuum L. during their early development. The results obtained suggest that there is both a developmental regulation and an organ‐specific expression of shikimate dehydrogenase in seedlings of C. annuum, seen mainly in the cotyledons. For example, shikimate dehydrogenase isoenzyme 3 was differentially expressed in cotyledons, but not at all in roots or hypocotyls. When the amounts of shikimate dehydrogenase were compared with the end‐products of the shikimate pathway, chlorogenic acid and lignins, it was observed that the fall in shikimate dehydrogenase activity in cotyledons coincided with a decrease in the concentrations of phenolics during primary leaf development. However, this did not seem to be the case with the hypocotyls, where the fall in phenolics was not related to the amount of shikimate dehydrogenase but rather to an increase in lignin deposition, supporting the view that chlorogenic acid might act as a precursor of the aromatic moiety of cinnamoyl alcohols during cell wall lignification.
Variations of the natural abundances of nitrogen and carbon isotopes in Triticum aestivum, with special reference to phloem and xylem exudates
Authors: YONEYAMA T. , HANDLEY L. L. , SCRIMGEOUR C.M. , FISHER D. B. , RAVEN J. A. 
Published: March 2003

summaryThis work explored whether the natural abundances of carbon and nitrogen isotopes could be used to describe the movement of C and X within wheat plants; we also considered whether isotopic analyses of aphids or their honeydew would substitute for direct analysis of phloem exudate.The δ13C of ears and roots (sinks) most closely matched those of the sugars + organic acids fraction (sources) in both growth stages; phloem δ13C matched that of leaf blade sugars. Xylem exudate δ13C matched no other putative (and measured) source in the ear‐forming stage and matched that of whole roots and ears in the grain‐filling stage. The δ15N of grain and roots (sinks) resembled that of leaf amino acids (sources) in the ear‐forming stage. In the gram‐filling stage, ear δ15N continued to resemble that of leaf amino acids, and δ15N of roots most closely resembled that of whole leaves. In the grain‐filling stage, phloem δ15N fell between that of leaf blade amino acids and that of whole leaves and was 15X‐depleted relative to internal and external NO, ‐N. In both growth stages, xylem exudate δ15N was less than that of soil NO3−‐N and more than that of residual soil N after mineral N extraction. The isotopic values are generally in agreement with data from other approaches, such as isotope labelling; they show NO3−‐N reduction in both shoots and roots of wheat and significant N recycling (root‐shoot‐phloem‐root) and C movement.Aphids might serve as a substitute for isotopic analysis of phloem δ15N. having the same value as their food source. Their excreta was 15N‐enriched relative to phloem.
Correlating molecular markers with physiological expression in Hordeum, a developing approach using stable isotopes
Authors: HANDLEY L. L. , ROBINSON D. , SCRIMGEOUR C. M. , GORDON D. , FORSTER B. P. , ELLIS R. P. , NEVO E. 
Published: March 2003

summaryThis paper describes a developing approach for correlating molecular markers with phenotypic expression in barley, and research examples are given. This approach is intended to elucidate the connection between denned parts of the barley genome and their physiological expressions. To illustrate our approach (up to the point of marker correlation), the materials, methods and results of an experiment are presented. Briefly, the natural abundance levels of carbon and nitrogen isotopes (δ13C δ15and N) serve as the primary screening tools for assessing barley genotypes for their responses to imposed abiotic stresses. The isotopic responses are then correlated with molecular markers as the first step in identifying the mechanisms relating genetic variation with phenotypic expression.A well‐described mechanistic model exists for interpreting plant δ13C, and this enables partitioning of the physiological processes contributing to the whole plant δ13C. Although plant δ15N appears to be equally well correlated with genotype and environment, there is no mechanistic model explaining this isotopic signature. Hence, δ15N is used empirically and in parallel with attempts to understand its underlying mechanism(s).
Dehydrins: genes, proteins, and associations with phenotypic traits
Authors: CAMPBELL SCOTT A. , CLOSE TIMOTHY J. 
Published: March 2003

summaryDehydrin proteins (late embryogenesis abundant (LEA) D11 family) are produced in a wide variety of plant species in response to environmental stimuli with a dehydrative component, including drought, low temperature, salinity, and developmental stages such as seed and pollen maturation. Despite their widespread occurrence and abundance in cells under dehydrative conditions, the biochemical role of dehydrins remains elusive. The subcellular location of dehydrins is consistent with a biochemical role as an intracellular stabilizer, possibly with surfactant characteristics, acting upon targets in both the nucleus and cytoplasm. In some species, dehydrin loci are located within quantitative trait loci (QTL) intervals for important phenotypic traits including winter hardiness in barley (Hordeum vulgare L.) and anthesis–silking interval in maize (Zea mays L.). Dehydrin loci tend to be multigenic and occur in clusters on more than one chromosome. Investigations are currently under way in our laboratory and others' to move beyond protein accumulation studies and correlations with QTL to uncover direct cause–and–effect relationships between dehydrin (dhn) genes and phenotypes associated with physiological responses to stress.
Potential NH4+ and NO3− uptake in seven Sphagnum species
Authors: JAUHIAINEN J. , WALLÉN B. , MALMER N. 
Published: March 2003

The rate of nitrogen uptake by seven Sphagnum species, which from a gradient from hummock to hollow and from ombrotrophic to minerotrophic conditions, was measured as the decrease in the concentrations of NH4+ and NO3− from solutions in which capitula were grown under laboratory conditions.The highest uptake rate was by individuals of each species with large capitula and a high number of ion exchange sites, i.e. lawn species (S. pulchrum, S. fallax, S. papillosum and S. magellanicum). On a dry‐mass basis, the most effective species were the hummock species (S. fuscum and S. rubellum), even though these species have a low dry mass. Hummock species, which occur in high densities and have high potential N‐uptake rates on a dry‐mass basis, were the most effective species in retaining available nitrogen.
Developmental and morphological responses of mycelial systems of Stropharia caerulea and Phanerochaete velutina to soil nutrient enrichment
Authors: DONNELLY DAMIAN P. , BODDY LYNNE 
Published: March 2003

Patterns produced by foraging mycelial systems of decomposer fungi might be the visual evidence of strategies for obtaining differently distributed carbon sources. Mycelial systems might also be responsive to unevenly distributed mineral nutrients in the soil. The nature of the mycelial response might differ between species inhabiting eutrophicated disturbed sites, such as Stropharia caerulea (Kriesel), and inhabitants of more typical woodland soils, such as Phanerochaete velutina DC.: (Pers.) Parmasto. We examined the effect of enrichment of soil by addition of different concentrations of N, P and potassium on inoculum decay rate and on extension rate, biomass production and fractal dimension (determined by image analysis) of extra‐resource mycelia of S. caerulea and P. velutina extending from wood blocks across compacted non‐sterile soil in trays. S. caerulea was more responsive than P. velutina to both type and quantity of soil nutrient enrichment. P. velutina grew more rapidly, produced more biomass and decayed inocula more rapidly than S. caerulea under most conditions, rates of growth and resource decay of the former remaining stable over a range of soil nutrient enrichments. In contrast, morphology of S. caerulea altered on enriched soils compared to controls with greater and more pronounced fanning (divergence of separate hyphae) of the foraging mycelial front. These changes were reflected in fractal values. Extension rate and biomass production of S. caerulea was less than controls on N‐amended soil, but greater on P‐amended soils, with the greatest biomass produced on 0·13–0·27 mg P g−1 air‐dried soil. Decay rate of inocula was often positively related with mycelial production rates. These responses indicate extra‐resource mycelium of S. caerulea is able to respond rapidly to a range of soil nutrient enrichments, and this is discussed in terms of the different foraging strategies exhibited by the two fungi.
Immunocytochemical studies of the infection mechanisms of Botrytis fabae II. Host cell wall breakdown
Authors: COLE L. , DEWEY F. M. , HAWES C. R. 
Published: March 2003

Immunoelectron microscopy using the anti‐pectin monoclonal antibody JIM 7 confirmed earlier observations that pectin degradation is a primary event in the process of host cell wall breakdown during the development of chocolate spot disease (causal agent: Botrytis fabae (Sard.)) of broad bean. Close examination of infected and non‐infected Vicia faba L. leaves indicated a loss of JIM 7‐labelling, and therefore, methyl‐esterified pectin, from swollen walls of infected and contiguous epidermal cells. Modified mesophyll walls also possessed less methyl‐esterified pectin than healthy walls. Enzymes which attack methyl‐esterified pectin appeared to be most active in regions of host tissue close to sites of fungal infection.Ultrastructural studies using the enzyme, cellobiohydrolase conjugated to gold (CBH1‐Au) revealed that the cellulose microfibrils of outer epidermal walls of non‐infected V. faba leaf tissue were heavily masked by other components of the plant cell wall. Such material was most probably pectin because the cellulose microfibrils of swollen epidermal and modified mesophyll walls of infected host tissue were heavily labelled with CBH1‐Au. These results were confirmed by double‐labelling studies using JIM 7 and CBH1‐Au. At early stages of the infection process, limited cellulose degradation was observed in infected leaf tissue.Double‐labelling experiments using the monoclonal antibody BC‐KH4 directed against Botrytis matrices and a marker for the plant cell wall (JIM 7 or CBH1‐Au) confirmed previous observations that the fungal matrices extended through modified host walls and degenerate cytoplasm. It is suggested that the wall‐modifying action of the pectin‐degrading enzymes produced during the infection process might facilitate pervasion of matrix material associated with the infection hyphae through host cell walls. Possible role(s) of such matrix material during the post‐penetration processes of the V. faba–B. fabae relationship are discussed.
Effects of solar radiation on the endemic Mediterranean red alga Rissoella verruculosa: photosynthetic performance, pigment content and the activities of enzymes related to nutrient uptake
Authors: FLORES‐MOYA ANTONIO , GÓMEZ IVÁN , VIÑEGLA BENJAMÍN , ALTAMIRANO MARÍA , PÉREZ‐RODRÍGUEZ EDUARDO , MAESTRE CRISTINA , CABALLERO ROSARIO M. , FIGUEROA FÉLIX L. 
Published: March 2003

The effects of full‐spectrum solar radiation and of solar radiation deprived of total u.v. radiation (λ<395 nm) on the endemic Mediterranean red alga Rissoella verruculosa (Bertoloni) J. Agardh were studied in situ in early summer, from sunrise to sunset. Photosynthetic performance, pigment content and the activities of enzymes related to nutrient uptake, were monitored under both radiation conditions throughout a daylight period.The doses of solar radiation, measured on the day during which the experiments were carried out (24 June 1997), were 9228·25, 1109·70 and 13·03 kJ m−2 for PAR (λ=400–700 nm), u.v.‐A (λ=315–400 nm) and u.v.‐B (λ=280–315 nm), respectively. Under these conditions, a clear daily variation in photosynthetic performance was found. However, no significant differences were detected between the two radiation conditions. At noon, strong sunlight impaired O2 evolution by 75%, but complete recovery occurred during the afternoon, reaching similar values to those measured in the early morning. By contrast, photoinhibition of optimal quantum yield (Fv/Fm), and the relative electron transport rate was followed by only a slight recovery during the afternoon. The rate of photosynthesis in air (simulating emersion conditions), estimated by CO2 exchange, showed a negative balance at noon, which was accentuated in plants exposed to the full‐solar spectrum.Significant changes in the activities of nitrate reductase and carbonic anhydrase were found throughout the day under both radiation conditions. In thalli receiving solar radiation deprived of u.v., total CA activity decreased throughout the day. However, in thalli exposed to full‐spectrum solar radiation, the activity of the enzyme tended to increase in the afternoon, correlating with an increase in NR activity.
Editorial
Authors: Ayres Peter 
Published: March 2003

New Phytologist welcomes this month, and introduces, its new Managing Editor, Jonathan Ingram. He comes to New Phytologist from Elsevier Science's Trends in Plant Science, where he has worked as Assistant Editor since the highly successful launch of that magazine in January 1996.Jonathan's introduction to plant science, at Oxford over 10 years ago, was through the excellent tuition of Vernon Butt in a traditional botany degree. He then took a DPhil with Andrew Smith and Chris Leaver, learning biochemical and molecular research methods while studying malate decarboxylation associated with Crassulacean acid metabolism. He subsequently moved to the Max Planck Institute for Breeding Research in Cologne, Germany, where he did research with Dorothea Bartels into the molecular mechanism of drought tolerance in the resurrection plant Craterostigma plantagineum, specifically the role of sucrose‐phosphate synthase.These are challenging times in science publishing, particularly as technological advances force rapid change, but there are also many exciting new opportunities. Jonathan's experience and background will help New Phytologist remain in the vanguard of plant journals, while maintaining its traditions of scientific excellence and friendly service to authors and readers, traditions carefully nurtured by his predecessor David Stribley.We wish David improved health and a happy retirement.