bluuebunny/crossref_metadata_2025_split huggingface dataset:
NITROGEN OXIDES PRODUCED DURING CO2 ENRICHMENT III. EFFECTS ON TOMATO AT DIFFERENT PHOTON FLUX DENSITIES*
Authors: MORTENSEN LEIV M. 
Published: May 2006

SUMMARYSeedlings of Lycopersicon esculentum (tomato) were subjected to CO2‐enriched air (1000 μl 1−1) containing 1.5 μ l−1 nitrogen oxides (NOX) for 25 d at four photon flux densities (30, 95, 175 and 250 μmol m−2 s−1 PAR).CO2 enrichment without NOx significantly increased the dry weights (47 to 93 %) at all light levels. Addition of NOx strongly reduced the mean dry weight at the lowest light level even below that of the unenriched control. At the two highest light levels, NOx reduced the dry weight, but much less than at the lowest level. NOX caused severe leaf injury at the lowest light level, but this effect disappeared with increased photon flux density.A system was constructed for measurement of the net CO., exchange rate (CER) for single plants. Short‐term measurements showed significant reductions of CER when the NO concentration was increased from 0 to 9μl 1−1 at 550μmol m−2 s−1 but almost no effect at 140 to 200 μmol m−2 s−1. NO caused similar percentage reductions of CER at 335 and 1000 μl 1 CO2. The absorption of NO was not significantly affected by increasing the photon flux density from 150 to 550μmol m‐2 s−2.
A COMPARATIVE STUDY OF GEUM RIVALE L. AND G. URBANUM L. TO DETERMINE THOSE FACTORS CONTROLLING THEIR ALTITUDINAL DISTRIBUTION
Authors: GRAVES J. D. , TAYLOR K. 
Published: May 2006

SUMMARYThe comparative growth of Geum rivale L. and Geum urbanum L. was determined, both over a range of temperatures under controlled conditions and throughout the year in field plots at three altitudes in the northern Pennines. Although under controlled conditions, the total dry matter accumulated was similar in both species, the change of relative growth rate with time was much more pronounced in G. urbanum than in G, rivale, especially at lower temperatures. In the field situation, there were no consistent differences in the overall growth pattern of the two species. The effect of altitude on growth was most pronounced during autumn and winter but was minimal in the summer. Root growth was less temperature‐sensitive than shoot growth in both species and was enhanced during the autumn. It is concluded that climatic limitation of growth is not so severe as to be the sole factor determining the altitudinal distribution of the species pair.
STAMEN FILAMENT STRUCTURE IN THE ASTERACEAE: THE ANTHER COLLAR
Authors: MEIRI L. , DULBERGER R. 
Published: May 2006

SUMMARYThe anther collar, i.e. the distal part of the stamen filament, was studied in 56 species belonging to 11 tribes of Asteraceae. In all the species, the structure of the collar differed considerably from that of the remaining part of the filament. Cells of the abaxial collar epidermis are large and have lignified walls. The cells of the adaxial epidermis are smaller and their walls, similar to epidermal cell walls in the remaining part of the filament, arc devoid of lignin. Variation was noted in the shape and size of the collar and in the thickenings of the epidermal walls. Presence of lignin in the collar indicates that this part does not participate in contraction of the filaments in species with sensitive stamens. It is suggested that the differences in structure and shape between the abaxial and adaxial sides of the collar determine an outward orientation of the curvature in the more elastic lower portion of the filament. This curvature leads to the formation of openings through which an insect may insert its proboscis to probe for nectar.
CALEDONIAN SCOTS PINE: ORIGINS AND GENETIC STRUCTURE
Authors: KINLOCH BOHUN B. , WESTFALL R. D. , FORREST G. I. 
Published: May 2006

SUMMARYMonoterpene and isozyme loci, used as markers to study the genetic structure of Scots pine (Pinus sylvestris L.) native to Scotland, showed that the endemic populations are not genetically impoverished, in spite of severe contraction in range and numbers as a result of both natural and anthropogenic causes. On the contrary, variability in the relict populations is almost the highest: of any plant species studied, with average heterozygosities of 0.33 for monoterpenes (rive loci) and 0.30 for isozymes (16 loci). The overwhelming proportion of this variability (> 95 %) was within populations, even though significant differences in gene frequencies of many individual loci existed among populations. Multiple‐locus comparison of gene frequencies among populations, resolved by canonical variate analysis, showed no coherent geographic pattern of differences from population to population or region to region, with one major exception: certain populations in northwestern Scotland (Wester Ross) were distinct from all others and each other. The pattern of variability of the biochemical markers was consistent with that of metrical and physiological traits reported in the literature. These traits, in turn, show relatively little genetic affinity between contemporary Scottish and continental European populations. The genetic evidence, together with the anomalous distribution of pine pollen in the British Isles during the Holocene, suggests that the Caledonian race of Scots pine originated endemically from more than one refugium after the last glaciation.
PLANTS AND PEAT CUTTINGS: HISTORICAL ECOLOGY OF A MUCH EXPLOITED PEATLAND ‐ THORNE WASTE, YORKSHIRE, UK
Authors: SMART P. J. , WHEELER B. D. , WILLIS A. J. 
Published: May 2006

SUMMARYAlthough many lowland raised bogs have been much modified or completely destroyed by agricultural reclamation, peat cutting, unaccompanied by reclamation, is not necessarily so destructive, and abandoned workings may provide a range of habitats that can support some of the original wetland plant species. Thome Waste, a much exploited raised bog in Eastern England, has a varied and well‐documented management history and comparatively good botanical records. It thus provides an exemplary site to assess the effect of peat exploitation upon its flora.The origin and development, and subsequent drainage, reclamation and peat extraction history of the site are described, and their impact upon the past and present flora is evaluated. Some ombrotrophic mire species have been lost from the site, but one section of peat cuttings (the Dutch canal system, abandoned about 1920) has revegetated and supports an important range of these plants. Fen species, which once occupied the marginal lagg, have been almost completely eliminated from their original sites (which have mostly been reclaimed) but many have become re‐established in various new habitats created within the peat‐cutting complex. This illustrates the potential of artificial modification of worked‐over peatland sites to sustain a range of wetland plants.
THE INFLUENCE OF ZINC ON THE CELL CYCLE IN THE ROOT MERISTEM OF A ZINC‐TOLERANT AND A NON‐TOLERANT CULTIVAR OF FESTUCA RUBRA L.
Authors: POWELL M. J. , DAVIES M. S. , FRANCIS D. 
Published: May 2006

SummarySeedlings of a zinc tolerant cultivar (Merlin) and a non‐tolerant cultivar (S59) of Festuca rubra L. were grown in aerated solution culture at various concentrations of zinc.The elongation of the longest root was much more inhibited by increasing Zn concentration in S59 than in Merlin. The mitotic index in the root meristem was reduced to a greater extent by increasing Zn concentration in S59 than in Merlin, whilst the cell doubling time (estimated by colchicine arrest) was increased by Zn much more in S59 than in Merlin.The kinetics of the cell cycle in the root meristem were determined by a pulse labelling experiment with low specific activity tritiated thymidine following a 4‐d exposure to three concentrations of Zn (0, 0.1 and 0.2 μg Zn cm−3). Treatment with 0.1 and 0.2 μg Zn cm−3increased the length of the cell cycle by 40 and 132 % respectively (compared with the zero Zn control treatment) in S59 but only by 6 and 16% respectively in Merlin. The increase in cell cycle length was due mainly to an increase in the duration of G1 in both cultivars; Zn had little effect on the duration of the other phases of the cell cycle.The growth fraction (the proportion of cycling cells in the meristem) was progressively reduced by increasing Zn concentration in S59 but was increased at 0.1 μg Zn cm−3in Merlin and then reduced to the control level at the higher Zn concentration.
EFFECT OF BENOMYL ON LEAF PHOSPHORUS CONCENTRATION IN ALPINE GRASSLANDS: A TEST OF MYCORRHIZAL BENEFIT
Authors: FITTER A. H. 
Published: May 2006

SummaryPhosphate and the fungicide, benomyl, were applied to two alpine grasslands in the Kananaskis Valley, Alberta, Canada, to test the hypothesis that a reduction in leaf phosphorus concentration should result from reduction in vesicular‐arbuscular mycorrhizal (VAM) infection if mycorrhizal hyphae are the main route of P uptake by roots.Benomyl successfully reduced infection in the roots of several species. At one site the result was an increase and not a decrease in leaf N and P concentrations, which was directly proportional to the original infection level, implying a benefit to the plant from the reduction in infection. At the other site, opposite trends were observed before and after a severe drought episode, implying that infection was initially deleterious and later beneficial. These results are adduced as evidence to support a hypothesis that VAM infection is only beneficial to plants under particular environmental conditions or at specific times in the year or life‐cycle.
GROWTH ANALYSIS OF MYCORRHIZAL AND NONMYCORRHIZAL BLACK OAK (QUERCUS VELUTINALAM.) SEEDLINGS
Authors: DAUGHTRIDGE ANN TODD , PALLARDY STEPHEN G. , GARRETT H. GENE , SANDER IVAN L. 
Published: May 2006

SummaryInoculation of seedlings of black oak (Quercus velutinaLam.) withPisolithus tinctorius(Pers.) Coker and Couch andSuillus luteus(L. ex Fr.) S. F. Gray stimulated total growth and several individual growth components as indicated by classical growth analysis of a 19‐week experiment. Inoculation withPisolithuswas more effective in increasing growth than was inoculation withSuillus.Mycorrhizal seedlings exhibited generally higher leaf area ratios than did uninfected seedlings from the seventh week after planting. Unit leaf rates (Ē) and relative growth rates (R̄) were higher for two of five harvest intervals in mycorrhizal plants, with the greatest values ofĒandR̄observed in seedlings inoculated withPisolithus.The alteration of growth patterns associated with inoculation was observed from six to nine weeks before substantial infection was detected. In general, mycorrhizal infection was associated with a greater relative investment of dry weight in leaf area and in early stimulation ofĒandR̄, a situation that increased total growth greatly as a result of early gains in productive plant mass.
β‐3‐DIMETHYLSULPHONIOPROPIONATE, PROLINE AND QUATERNARY AMMONIUM COMPOUNDS IN SPARTINA ANGLICA IN RELATION TO SODIUM CHLORIDE, NITROGEN AND SULPHUR
Authors: Van DIGGELEN J. , ROZEMA J. , DICKSON D. M. J. , BROEKMAN R. 
Published: May 2006

Summary Spartina anglica Hubbard seedlings were grown in nutrient solutions containing various concentrations of sodium salts, as the chloride, sulphate and sulphide. Two levels of nitrate were supplied to plants growing on the sodium chloride and sodium sulphate series. At low sodium chloride concentrations, higher growth rates were found in plants grown on the high nitrate level. At higher salinities, growth was inhibited and the inhibition was similar for plants grown on either of the two nitrate levels. Shoot levels of β‐3‐dimethylsulphoniopropionate (DMSP) showed no significant increase with increasing sodium chloride concentrations, at both nitrate levels. This strongly indicates that DMSP does not act as a compatible solute in S. anglica, grown under salt stress. Contrary to DMSP, levels of proline and quaternary ammonium compounds (QAC's) increased significantly in response to sodium chloride, and were significantly higher in plants grown on the high nitrate concentration. The influence of nitrogen availability on the accumulation of N‐containing compatible solutes and growth is discussed. Growth rates of plants grown in increasing sodium sulphate concentrations were not inhibited. DMSP levels in plants did not increase with a sulphate increase in the medium. A significant inhibition of plant growth by sodium sulphide was found. Sulphate in the plant increased with increasing sulphide levels in the nutrient solution and an increase of DMSP was found at the highest sulphide level. A possible function of DMSP as storage for excess sulphur is discussed.
ARE UNISEXUAL FLOWERS PRIMITIVE?
Authors: THOMPSON K. 
Published: May 2006

SummarySporne's statistical evaluation of primitiveness in angiosperms has generated a good deal of controversy, mainly because his identification of unisexual flowers as primitive is at variance with most other interpretations of angiosperm evolution. The controversy can be resolved by taking account of the fact that (a) the bisexual and unisexual states are readily interchangeable and (b) there are good adaptive reasons for expecting unisexual flowers to be correlated with woodiness. Given that woodiness is Sporne's most important indicator of primitiveness, the apparent evaluation of unisexual flowers as primitive is seen to have an adaptive rather than phylogenetic basis.
LOCALIZATION OF NITRATE REDUCTION IN FERNS AND ITS RELATIONSHIP TO ENVIRONMENT AND PHYSIOLOGICAL CHARACTERISTICS
Authors: STEWART GEORGE R. , POPP MARIANNE , HOLZAPFEL INGEBORG , STEWART JANICE A. , DICKIE‐ESKEW ANN 
Published: May 2006

SummaryThe capacity for nitrate reduction was shown to be present in the roots and shoots of all fern species examined. In many species the root was the major site of nitrate reduction, irrespective of the availability of external nitrate. The capacity for root nitrate reduction was positively correlated with root glutamine synthetase activity. Some species exhibited multiple forms of glutamine synthetase in their shoots. The activity of chloroplastic glutamine synthetase appeared to be correlated with photorespiratory potential. Root nitrate assimilation was most pronounced in shade ferns.
AN INVESTIGATION INTO NITROGEN ASSIMILATION AND DISTRIBUTION IN FRUITING PLANTS OF BARLEY (HORDEUM VULGARE L. cv. CLIPPER) IN RESPONSE TO NITRATE, AMMONIUM AND MIXED NITRATE AND AMMONIUM NUTRITION
Authors: SOARES M. I. M. , LEWIS† O. A. M. 
Published: May 2006

SummaryBarley plants (Hordeum vulgare L. cv. Clipper) were grown to maturity in pH‐controlled, aerated solution culture with 2 mM inorganic 14N supplied as nitrate alone, ammonium alone or 1:1 nitrate+ammonium. At the end of the eighth week of growth, when seed filling was well advanced, the 14N feeding solutions were replaced by 15N feeding solutions, and the plants were grown in these media for 6 and 12 h before harvesting. l5N analyses of the plant material show that even at this late developmental stage, barley plants are still accumulating and assimilating considerable quantities of nitrogen (N), although at a much slower rate than in younger plants. Much of this N is incorporated into leaf protein. Transport of newly assimilated N from vegetative to reproductive parts is rapid, 22% of the assimilated (organic) l5N being found in the seed of NO3−‐fed plants at harvest, 26 % in NH4+‐fed plants and 17 % in NH4+‐fed plants. Inorganic N sources are not translocated to the seed in significant quantities. NH4+ and NH4++ NO3 ‐ fed plants show a much more rapid incorporation of N into both vegetative and reproductive organs than do NO3−‐fed plants; seeds of NH4++ NO3−‐fed plants gained organic 15N at a rate of 86 μg h−1 per plant, NH4+‐fed plants at 55 μg h−1 per plant and NO3−‐fed plants at 21 μg h−1 per plant. The poor organic 15N accumulation observed in NO3−‐fed plants is ascribed to the slow absorption rate of NO3− ions relative to NH4+ ions and the low nitrate reducing potential of the vegetative organs of the plant at this stage of development.
AMINO ACID AND AMIDE METABOLISM IN THE HULLS AND SEEDS OF DEVELOPING FRUITS OF GARDEN PEA, PISUM SATIVUM L. IV. ALANINE
Authors: MURRAY D. R. 
Published: May 2006

SummaryPea plants (Pisum sativum L. cv. Melbourne Market), each with a single developing pod, were pulse‐fed [14C]alanine supplied through the cut stem. The stages of pod development chosen were from 14 to 21 d after full blossom when alanine is one of the principal nitrogenous solutes secreted by the seedcoats into the embryo sac. In addition, [14C]alanine was supplied to a detached 14 d old pod via the base of the cut peduncle. After 24 h, the peduncles, hulls, seed components, and where appropriate, parts of the subtending leaf, were separated and frozen for later analysis. The distribution of label in soluble metabolites was determined by paper chromatography and radioautography. Of the total label in metabolites secreted into the embryo sac, only about 4% remained associated with alanine (14 d stage); when [14C]alanine was fed via the stem, most of this label was in sucrose (60%) and glutamine (27%), but when [14C]alanine was fed via the peduncle, most of the label entering the embryo sac was in glutamine. The results confirm that most of the alanine secreted into the embryo sac is synthesized in the seedcoats de novo from other solutes, notably asparagine.
PROPERTIES AND IMMUNOCHEMICAL CHARACTERIZATION OF NADPH‐SPECIFIC GLUTAMATEDEHYDROGENASE FROM EUGLENA GRACILIS
Authors: JAVED QAMAR , MERRETT MICHAEL J. 
Published: May 2006

SummaryThe NADPH–glutamate dehydrogenase (GDH; EC 1.4.1.4) from glutamate–grown cells of Euglena gracilis Klebs strain z. Pringsheim was purified to homogeneity by the criterion of polyacrylamide gel electrophoresis. The holoenzyme was shown to have a relative molecular mass of 180000 and to be composed of four subunits with a relative molecular mass of 45000. The pH optimum for the animating reaction was 80. The Km values for NH4+, α‐oxoglutarate and NADPH were 0.4 mM, 1.4 mM and 0.18 mM, respectively.Antibodies raised to the purified enzyme showed no immunological correspondence with glutamic dehydrogenases from nitrate–grown Stichococus bacillaris and Porphyridium cruentum or ammonium–grown Chlorella vulgaris on Ouchterlony double–diffusion gels or by immuno–precipitation of enzyme activity. It is concluded that antigenic sites on the tetrameric Euglena enzyme may not be available on other NADPH–GDHs if they are hexamers.
STRUCTURAL CHARACTERISTICS OF ECTENDOMYCORRHIZAS SYNTHESIZED BETWEEN ROOTS OF PINUS RESINOSA AND THE E‐STRAIN FUNGUS, WILCOXINA MIKOLAEVAR. MIKOLAE
Authors: PICHÉ Y. , ACKERLEY C. A. , PETERSON R. L. 
Published: May 2006

SummaryEctendomycorrhizas were synthesized between Pimis resinosa Ait. (red pine) and the E‐strain fungus, Wilcoxina mikolae var. mikolae (Yang and Wilcox) Yang & Korf in growth pouches. A rudimentary mantle consisting of a few hyphae embedded in a matrix was formed. Although a I Iartig net was formed, the predominant phase consisted of intracellular hyphae in cortical tells of lateral and main roots. Cortical cells in basal portions of lateral roots showed various degrees of senescence, and hyphae in these cells were highly vacuolated.
THE EFFECTS OF SIMULATED ACID RAIN ON GERMINATIVE CAPACITY, GROWTH AND MORPHOLOGY OF FOREST TREE SEEDLINGS
Authors: PERCY KEVIN 
Published: May 2006

SummaryAcid rain‐induced direct injury to forest tree seedlings was investigated in specially designed controlled‐environment simulated‐rainfall chambers. Seed germinative capacity, seedling survival, seedling growth and morphological responses to simulated rains of pH 5.6, 4.6, 3.6 and 2.6 were examined during the first growth cycle in 11 commercially important north temperate tree species. Germinative capacity was weakly responsive to rain pH, while seedling survival was more sensitive. No evidence of macroscopic foliar injury was observed at rain pH > 2.6. 1 reatment with pH 4.6 rain was sufficient to induce statistically significant growth reductions and morphological changes in coniferous seedlings. Response varied with species, treatment pH and parameter measured. No consistent growth stimulations were observed. Initiation of Primary needles, axillary meristems and shoot apex height were most affected by simulated pH. Deciduous species were considerably more resistant than coniferous species. Treatment with ram of pH 2.6 was generally required to induce significant growth reductions in deciduous seedlings.
A study to compare the oral health impact profile and satisfaction before and after having replacement complete dentures constructed by either the copy or the conventional technique
Authors: Scott B.J.J. , Forgie A.H. , Davis D.M. 
Published: May 2006

Aims:  To assess the oral health impact profile (OHIP) on edentulous subjects who needed to have their dentures replaced either by a copy technique or a conventional technique, and to determine whether any change in the subjects’ assessment of their original and replacement dentures impacted on oral health related quality of life parameters.Background:  The OHIP is an instrument used to measure subjects’ perceptions of the social impact of oral disorders on their well being. Changes in the OHIP may occur when subjects need to have their complete dentures replaced. Furthermore, it is possible that the method by which the dentures are constructed may impact on this.Methods:  A total of 65 edentulous subjects were studied. Thirty‐three subjects had their dentures constructed by a copy technique and 32 by a conventional technique. Subjects completed the OHIP‐14 questionnaires before and after being provided with a set of replacement complete dentures. They also assessed specific features of the upper and lower dentures. Responses were recorded on a Likert scale.Results:  For many subjects, the responses in the before treatment questionnaires were at the lower end of the Likert scale, indicating that there were no major impacts on oral health related quality of life parameters. There were no major differences between the copy denture subjects and the conventional denture subjects in relation to the change in OHIP scores before and after treatment. Generally subjects expressed improved satisfaction with the new lower denture. However, for the copy denture group there were significant improvements for all seven assessments compared with only five out of seven assessments for subjects in the conventional group.Conclusion:  For these groups of edentulous subjects, although they may need dentures to be replaced after a period of wear, this does not necessarily have significant impacts on oral health related quality of life parameters. It seems likely that this is the main reason why the provision of new dentures by either a copying or conventional technique did not result in major changes to the OHIP.