bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of the shikimate pathway in the leaves of vascular plants exposed to air pollution
Authors: KATOH T. , KASUYA M. , KAGAMIMORI S. , KOZUKA H. , KAWANO S. 
Published: April 2006

SUMMARYIntermediate products of tannin biosynthesis, i.e., glucose, shikimic acid and phenolics, Were determined in order to estimate the sites of inhibition of tannin synthesis, which had previously been observed in leaves of Japanese Cedar (Cryptomeria japonica D. Don.) collected from the surroundings of a steam power station. The effects of SO2, on tannin biosynthesis were also investigated in experimental fumigations of C. japonica saplings. The results of these studies indicated that inhibition of aromatic ring formation, i.e., the process converting shikimic acid to phenylalanine and tyrosine (the later shikimate pathway), was caused by slight air pollution.
Stimulation of ectomycorrhizal infection of Pinus radiata by some microorganisms associated with the mantle of ectomycorrhizas
Authors: GARBAYE J. , BOWEN G. D. 
Published: April 2006

SUMMARYMicroorganisms were isolated from inside the mantle of ectomycorrhizas formed by the fungus Rhizopogon luteolus Fr. and Nordh on the roots of Pinus radiata D. Don. growing in a sandy podzol. Different isolates of these microorganisms were then tested for their effect on three stages of mycorrhizal infection : growth of the fungus into the soil, growth along the root, and mycorrhiza formation. Experiments were performed in axenic and non‐axenic conditions. A significant microbial population was present within the mantle of ectomycorrhizas (Gram negative bacteria being dominant) and a majority of these had a stimulating effect on mycelial growth of R. luteolus and/or mycorrhiza formation. These results suggest that some specific microbial communities have evolved to live in close association with ectomycorrhizal fungi in their symbiotic state, with mutual benefit. The potential use of such‘helper’microorganisms for improving the efficiency of ectomycorrhizal inoculation in forest nurseries is discussed.
Studies on nitrogen metabolism of Terfezia spp. and Tirmania spp.
Authors: EWAZE JULIET O. , AL‐NAAMA MENHEL M. 
Published: April 2006

SUMMARYSpecies of the truffle fungi Terjezia and Tirmania are widespread in the south of Iraq in association with roots of Helianthemum spp., the dominant plants of the area. The truffle mycelia and ascocarps reduced nitrate at much higher rates than did Helianthemum rootlets, suggesting that absorption of nitrate is particularly enhanced by the fungal symbiont.Measurements of the specific activity of representative enzymes of the ornithine cycle indicated that this cycle was operative in ascocarp tissue and led to the acccumulation of urea. It is suggested that this may serve an osmotic function, assisting spore liberation.
Rate of accumulation of fructan oligomers in wheat seedlings (Triticum aestivum L.) during the early stages of chilling treatment
Authors: BANCAL P. , GAUDILLÈRE J. P. 
Published: April 2006

summaryThe accumulation of soluble carbohydrates was studied during chilling of 2‐week‐old wheat (Triticum aestivum L.) seedlings. The extracts were analysed using a C18 HPLC method separating hexoses, sucrose and a wide range of oligofructan. Isomers were recognized and their content determined. The amounts of hexoses, sucrose and the trisaccharides 1‐kestose and 6‐kestose increased at the beginning of the treatment. The accumulation rate of 1‐kestose, the trisaccharide generally considered to be the precursor of fructan, increased ten fold with some delay. Heavier fructan accumulated even later. In leaf blades, 1–3 molecular species with a degree of polymerization from 4 to 8 were detected. Five of these accounted for 90% of this pool at day 5. In leaf bases the amount of carbohydrates was lower but more species of fructan were detected. The sequence of accumulation was the same as in the blades. These results are discussed in relation to current models ot fructan synthesis.
The possibility of determining the age of colonies of clonally propagating herbaceous species from historic records: the case of Aster novi‐belgii L. (first recorded as A. salignus Willd.) at Wicken Fen Nature Reserve, Cambridgeshire, England
Authors: BRIGGS D. , BLOCK M. , JENNINGS S. 
Published: April 2006

summaryFor a number of species, population biologists have estimated the age of apparent clones. In studying a colony of naturalized Aster novi‐belgii L. (first recorded as Aster salignus Willd.) growing at Wicken Fen Nature Reserve, Cambridgeshire, England, we have attempted to determine from a considerable body of historic records, its age, structure and development. While it is highly likely that the records refer to the colony in its present position on the Fen, there is uncertainty about its age and conflicting information about its position. A. novi‐belgii is a self‐incompatible species. Plants of the Wicken colony exhibit little variation and preliminary tests show that their achenes are sterile. As a working hypothesis, for further testing, we suggest that all the plants may be of a single clone.Population biologists, who are interested in determining the age and development of clones of plants, are likely to be disappointed both by the extent and the vagueness of historic records. This situation is understandable as the information was recorded for taxonomic purposes. The hope is expressed that the intensive studies now being made of populations of plants will result in the long‐term survival in the public domain of detailed records and maps, which will enable future generations to study the age and development of clones of herbaceous species.
Ecological genetics of salt resistance in the clonal perennial, Agrostis stolonifera L.
Authors: KIK C. 
Published: April 2006

SummaryLarge population differentiation in salt resistance, as determined by a rooting technique, was detected among four ecologically contrasting populations at. Agrostis stolanifera L., with known genotypic compositions. It was found that an inland meadow population had a significantly lower salt resistance than the more maritime populations; and that only the inland meadow population had a significant genetical component for salt resistance.The possible adaptive value of salt resistance, as measured by the rooting technique, was evaluated in a transplant experiment in a natural salt marsh. It was found that relative root growth is a reasonable indicator of the complex of factors determining salt resistance. A detailed analysis of the relationship between salt resistance and survival within each of the four populations of A. stolonifera suggested that genotype x environment interaction and trade‐offs between characters governing salt resistance might play a significant role.
Enzymatic, lectin, and morphological characterization and classification of presumptive cyanobionts from Azolla Lam
Authors: ZIMMERMAN WILLIAM J. , H.ROSEN BARRY , LUMPKIN THOMASA. 
Published: April 2006

SummaryA number of cyanobacterial strains from the Azolla Lam. symbiosis, all independently isolated by different researchers, were simultaneously evaluated in order to document distinguishing traits. Ten presumptive secondary (minor) cyanobionts from Azolla were identified by genus and compared by morphology, binding to FITC‐conjugated lectins, and enzyme electrophoresis. Identification of allozymes was particularly helpful in differentiating among strains. Anabaena variabilis ATCC 24413 and Anabaena sp. PCC 7120 served as the free‐living control taxa. Based on morphological features, six strains identified as Anabaena and four as Nostoc. Those identified as Anabaena closely resembled one another morphologically and in general did not bind to lectins. In their banding patterns of 12 enzymes, five of the Anabaena cultures were identical to each other and to A. variabilis. No correlation was found between this group of cyanobaionts and any single Azolla host species. The Nostoc strains were each distinctive in appearance, and unrelated enzymatically. Cells of only one Nostoc, from India and judged to be an epiphyte rather than a symbiont, reacted with certain lectins (Canavalia, Erythrina, Phytolacca and Triticum). Culturable cyanobacteria from Azolla, previously asserted to be either Anabaena or Nostoc exclusively, have now been observed to belong to both genera.
The biology of mycorrhiza in the Ericaceae
Authors: SHAW G. , READ D. J. 
Published: April 2006

SummaryThe effects of the metals, iron and aluminium, on acid phosphatase (P‐NPPase) activity of the ericoid endophyte, Hymenoseyphus ericae (Read) Korf and Kernan were determined. The endophyte was grown in pure culture and then treated with Fe2+ and Al2−over a range of concentrations (0–1000mgl−1), and at two concentrations of inorganic phosphorus (20μ and 200 μM p). Activities of p‐NPPase were determined. Enzyme activity was greatly inhibited at the highest concentration of external P even in the absence of the metal ions. The presence of the metals in the low P treatment had effects determined by their concentration. At the highest concentration used, they precipitated products of acid phosphatase activity (p‐NP), and so invalidated the use of the assay at these metal levels. However, the assay could reliably be used over the concentration range 0–200 mg 1−1 Al2+ and 1–100 mg 1 −1 Fe2+, the upper concentrations in both cases being considerably above those normally found in soil solutions. Over these ranges the presence of Al3+ only slightly inhibited p‐NPPase activity, whereas there was a small increase of activity in the case of Fe2+. The results are discussed in relation to the role of ericoid mycorrhizal infection in the phosphorus nutrition of ericaceous plants in natural ecosystems.
Mycorrhizal synthesis in vitro between Glomus spp. and artificial seeds of alfalfa
Authors: STRULLU D. G. , ROMAND C. , CALLAC P. , TÉOULÉ E. , DEMARLY Y. 
Published: April 2006

SummaryArtificial seeds of alfalfa (Medicago sativa L.), consisting of somatic embryos encased in a nutritive coating, were inoculated with Glomus. In vitro the fungus, regenerated from surface sterilized root fragments, formed typical vesicular‐arbuscular mycorrhizas.
Effect of nitrogen source on growth response to salinity stress in maize and wheat
Authors: LEWIS O. A. M. , LEIDI E. O. , LIPS S. H. 
Published: April 2006

summaryThe effect of ammonium and nitrate nutrition on maize and wheat grown hydroponically and salinity stressed was assessed from measurements of growth rate and gas exchange. In both maize and wheat the ammonium‐grown plains were much more sensitive to salinity toxicity than nitrate‐grown plants particularly when exposed to 60–80 mM salinity. Shoot growth was retarded to a far greater extent than root growth in salinity‐stressed plants of both wheat and maize with either nitrogen source.There was no significant decrease of photosynthetic rate in salinity‐stressed plants of either species fed nitrate or ammonium, except in severely wilted plants of both species fed nitrate or ammonium at the highest (80 mM) salinity concentration. The same was true for stomatal conductance, transpiration rate and transpiration ratio (water use efficiency). In nitrate‐fed wheat, raising the calcium concentration from 2 to 12 mM in the presence of 60 mM salinity produced an 11% increase in growth. This effect is ascribed to improved nitrate uptake due to calcium protection of the nitrate transporter and was not evident in ammonium‐grown wheat. Possible reasons for the differential effects of ammonium and nitrate nutrition are discussed.
Sugar uptake and invertase activity in Dendrobium tissues
Authors: HEW C. S. , MAH T. C. 
Published: April 2006

summaryUndifferentiated and differentiated tissues of Dendrobium exhibited no difference in their preference for sugars. The uptake of sugars was more rapid by undifferentiated tissue. Fructose provided the best carbon source for both tissues. Sucrose was hydrolysed before it was taken up, as the result of invertase activity. Both acid and alkaline invertase were present and invertase activity was detected in the soluble and cell wall fraction. There was a gradual increase in invertase activity of tissues grown in sucrose‐containing medium with time but not in tissues grown in fructose‐containing medium.
Ectomycorrhizal formation by micropropagated clones of Eucalyptus marginata inoculated with isolates of Pisolithus tinctorius
Authors: TONKIN C. M. , MALAJCZUK N. , McCOMB J. A. 
Published: April 2006

summary Eucalyptus marginata Donn ex Sm. and Pisolithus tinctorius (Pers.) Cok and Couch were co‐cultured to obtain ectomycorrhizal formation in vitro. One isolate of P. tinctorius formed mycorrhizas with aseptic seedlings of a juvenile clone derived from a 4‐month‐old seedling, and four clones derived from crowns of mature trees. A second P. tinctorius isolate formed mycorrhizas with only the clones from mature trees. Successful combinations resulted in formation of a mantle followed by a Hartig net and epidermal cell elongation. The fungal/seedlings or fungal/seedling clone combinations which did not produce ectomycorrhizal roots, were characterized by a mantle but lacked a Hartig net, and formed an abundance of polyphenols throughout the root. Genotype, maturity and fungal specificity are key factors influencing successful ectomycorrhizal formation on E. marginata by P. tinctorius in vitro.
Electrophoretic and immunological studies on acid phosphatase from a mycorrhizal fungus of Erica hispidula L.
Authors: STRAKER C. J. , GIANINAZZI‐PEARSON VIVIENNE , GIANINAZZI S. , CLEYET‐MAREL J.‐C. , BOUSQUET N. 
Published: April 2006

summaryWall‐bound acid phosphatases of an endomycorrhizal fungus of Erica hispidula L. were separated by PAGE, electrotransferred to nitrocellulose membranes and glycoprotein characteristics studied using Concanavalin A. An antiserum was raised against the major high‐molecular‐weight acid phosphatase and its specificity demonstrated by immunoblotting and ELISA. The antiserum reacted very little with protein extracts of other cellular fractions and was unable to bind to wall‐bound protein antigens of a mycorrhizal isolate from K. mauritanica. Ultrastructural localization of acid phosphatase by cytoenzymology and indirect immunogold labelling showed it to be almost exclusively associated with the fungal wall and septa of living hyphae, whilst in senescent hyphae it was also present within the disorganized cytoplasm.
Ecophysiology of xerophytic and halophytic vegetation of a coastal alluvial plain in northern Venezuela
Authors: MEDINA E. , CRAM W. J. , LEE H. S. J. , LÜTTGE U. , POPP M. , SMITH J. A. C. , DIAZ M. 
Published: April 2006

summaryThis paper describes the ecology of a coastal alluvial plain at Chichiriviche in northern Venezuela. The area supports a great diversity of plant communities, ranging from mangroves on the seaward edge of the plain to non‐halophytic, fresh‐water communities on the landward side. Small differences on topography result in a mosaic of saline and less‐saline environments. Rainfall is strongly seasonal, causing superficial flooding of the alluvial plain in the rainy season and the creation of a hypersaline Substratum during the dry season. As a consequence, much of the plain is devoid or vegetation. Towards the landward side of the plain there are numerous small ‘vegetation islands’, fringed by halophilic succulent herbs, and made up of deciduous and semi‐deciduous shrubs and trees together with non‐halophytic CAM plants such as cacti and bromeliads. In subsequent papers the results of ecophysiological studies of these diverse plant species are presented.
The influence of photoperiod on incorporation of precursors into tocopherols and plastoquinone in Xanthium strumarium L.
Authors: TORRES J. MOLINA , LAIDMAN D. L. , GAUNT J. K. 
Published: April 2006

summaryRadioactivity from tyrosine applied to leaves of Xanthium strumarium L. was incorporated into α‐ and γ‐tocopherol and plastoquinone. Time‐course studies on vegetative plants showed that γ‐tocopherol was rapidly labelled and turned over, while α‐tocopherol showed no sign of turnover. The same pattern was observed in the light and in darkness. Plastoquinone synthesis was rapid in the light but it was greatly reduced in the dark. Following floral induction the accumulation of radioactivity in γ‐tocopherol was at first slower, but it later readied higher levels than in the vegetative plants. Total incorporation into α‐tocopherol and plastoquinone was greatly reduced.
Peroxidase isoenzyme patterns of resistant and susceptible wheat leaves following stem rust infection
Authors: FLOTT BERENIKE E. , MOERSCHBACHER BRUNO M. , REISENER HANS‐JOACHIM 
Published: April 2006

Near‐isogenic lines of the wheat (Triticum aestivum L.) cultivar Prelude, currying either the sr5 gene for susceptibility or the Sr5 allele for resistance to stem rust (Puccinia graminis Pers. f. sp. tritici Erics. & E. Henn.) were inoculated with race 32 of the fungus which possesses the P5 gene for avirulence. Enzyme extracts prepared at different times after inoculation were separated by non‐denaturing gel electrophoresis and the gels were stained for peroxidase activity using different substrates. Both anodic and cathodic gels were run.In anodic separations, resistant and susceptible plants initially both exhibited decreases in the activity of two isoenzymes of low molecular mass, increases in two enzymes of intermediate molecular mass, and induction of two low high molecular mass isoperoxidases. In susceptible plants, these changes proceeded until 3 days after inoculation, when a general decrease in all isoenzymes was observed until 8 days after inoculation. In contrast, in resistant plants, the increases continued up to 7 days after inoculation. In addition, one isoperoxidase appeared about 2–3 days after inoculation only in the incompatible interaction.Cathodic separations revealed that basic isoperoxidases increased after inoculation as well. In the group of small basic isoenzymes, two new bands appeared following inoculation. Only slight differences were seen between the two isolines.Injecting an elicitor isolated from germinated urediniospores into the intercellular spaces of wheat leaves induces typical symptoms of the resistant reaction in both isolines. Correspondingly, the isoperoxidase pattern of the incompatible interaction, including the resistance related isoenzyme, was induced in both isolines.The results are compared with previously reported changes in enzyme activities of the lignin biosynthetic Pathway, including the total activity of peroxidase. The relationship of different isoenzymes to the lignification response as a decisive mechanism of the hypersensitive resistant reaction is discussed.
Resource relationships of foraging mycelial systems of Phanerochaete velutina and Hypholoma fasciculare in soil
Authors: DOWSON C. G. , SPRINGHAM P. , RAYNER A. D. M. , BODDY LYNNE 
Published: April 2006

summaryInoculum blocks of wood colonized by the basidiomycetes Hypholoma fasciculare (Huds.: Fr.) Kummer and Phanerochaete velutina (DC: Pers.) Parmasto were placed in plastic trays containing moist (matric potential −0.007 MPa), unsterilized soil. When ‘baits’, in the form of beech (Fagus sylvatica L.) wood blocks, descaled pine (Primus sylvestris L.) cones, beech twigs, beech leaves or pine needles were introduced, H. fasciculare consistently responded by ramification of diffuse mycelium within and over the baits, inhibition of extension and regression of non‐connective mycelium, thickening of connective cords and polarized outgrowth from the baits. Decay of inoculum wood blocks was generally greater in the control than where baits were added. Whilst the decay rates of different types of baits varied, pine cones being least decayed, total loss of dry weight from the system (inocula and baits combined) was similar in all cases. The sparser, more independent and rapidly extending cords of P. velutina exhibited more varied responses to the introduction of baits, and only under certain circumstances exhibited the same responses as H. fasciculare. Although decay of inoculum blocks was generally greater in controls than where colonizable baits were added, total loss of dry weight in the latter systems was two‐ to fourfold greater than in controls.Snowflake‐like mycelial growth patterns were induced in H. fasciculare by growing the fungus from an inoculum block placed in the centre of two concentric, hexagonal arrays of wood‐block baits. Selective removal of baits from the inner hexagonal array, after they had been colonized but before renewed outgrowth from them, either greatly delayed colonization of outlying blocks, if all six were taken out, or led respectively to symmetrical or asymmetrical ‘bypass’ systems if three alternating or adjacent blocks were taken.These observations are further support for the interpretation of basidiomycete mycelial cords as foraging systems and suggest experimental approaches which can help to elucidate their behaviour.
Protein secretion in plants
Authors: JONES RUSSELL L. , ROBINSON DAVID G. 
Published: April 2006

summaryProtein secretion is an ubiquitous but poorly understood process in plants. Secreted proteins are synthesized on the membranes of the rough endoplasmic reticulum and transported to the cell surface by secretary vesicles formed at the Golgi apparatus. Whereas many of the structural details of this process are known the mechanisms underlying secretion are just beginning to be understood, in this article we review some of the recent developments in this field, and we compare the progress made with animal and plant cells.

CONTENTS

Summary
567

I.
Introduction
568

II.
Proteins secreted by plants
568

III.
Synthesis and post‐translational modification of secreted proteins
571

IV.
Molecular requirements for secretion
576

V.
Vehicles of secretory transport
581

VI.
Regulation of secretion
585

VII.
Conclusions and Perspective
587

Acknowledgements
588

References
588
Cadmium tolerance and co‐tolerance in Silene vulgaris (Moench.) Garcke [=S. cucubalus (L.) Wib.]
Authors: VERKLEIJ J. A. C. , PRAST J. E. 
Published: April 2006

summaryThis paper is the first to report cadmium tolerance in a dicotyledonous species, Silene vulgaris (Moench.) Garcke. The response to cadmium of five populations originating from one uncontaminated and various heavy‐metal contaminated sites was examined under standardized conditions for three weeks. The tolerance index (TI), based on the mean relative growth rate (R), was determined.Populations originating from cadmium‐contaminated sites showed a distinct tolerance to cadmium. A population from a site enriched only with copper also exhibited a marked co‐tolerance to cadmium. A clear difference in biomass production between the sensitive and tolerant populations was attained at 1 μM cadmium. An optimum biomass production in tolerant populations at a metal concentration higher than in the control, as demonstrated for zinc and copper, could not be established for cadmium.The pattern of cadmium uptake and translocation differed between tolerant and sensitive populations. All tolerant populations accumulated cadmium in the roots and showed some degree of restricted transport to the shoots. The effect of cadmium on the elemental distribution in roots and shoots was population‐independent for some elements (copper, zinc, potassium) and population‐specific for others (phosphorus, magnesium and sodium). The phenomenon of co‐tolerance to cadmium is discussed in relation to possible tolerance mechanisms, especially with regard to metal‐binding compounds (metallothioneins, phytochelatins).