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111.
Leo Hausta 《Forstwissenschaftliches Centralblatt》1924,46(10):517-534
Ohne Zusammenfassung 相似文献
112.
113.
Meg Simpson Roger D. McLenaghen Ivan Chirino-Valle Leo M. Condron 《Biology and Fertility of Soils》2012,48(5):607-611
Relationships between the relative solubility of soil phosphorus (P) and short-term plant P uptake were investigated using soils obtained from a field trial that had been maintained under contrasting mowing regimen (no mowing, mowing with clippings left, mowing with clippings removed) for 15?years. In a glasshouse pot experiment, P uptake by red clover and Italian ryegrass was found to be 40% lower for the clippings removed treatment compared with the no mowing treatment, which was consistent with the fact that concentrations of readily extracted inorganic P were 42% lower in the clippings removed treatment soil. However, P uptake was 51–54% higher for the clippings left treatment soil compared with no mowing, despite the fact that levels of readily extracted soil inorganic P were similar in both treatments. This indicated that biological and biochemical processes associated with enhanced mineralisation of organic P and turnover of P through the microbial biomass made a greater contribution to increased plant P uptake in the clippings left soil compared with the other treatments. These findings highlight the importance of soil biological processes in determining the P nutrition and productivity of managed grasslands. 相似文献
114.
Paul J. Hunter Leo A. Calvo-Bado Nick R. Parsons Tim R. Pettitt Geoff M. Petch Eve Shaw J. Alun W. Morgan John M. Whipps 《Irrigation Science》2013,31(4):631-642
The effect of microbial colonization on the function and rejuvenation of slow sand filters was investigated using culture-independent profiling. Colonization resulted in significant reduction in filter pore size, which may be important in order to fully remove pathogens, but was not associated with a specific microbial component. Communities were highly variable, and no common microbial groups were found in effective filters. Bacterial community composition was affected by sand particle size, although high levels of microbial turnover during filter maturation suggested that this was unlikely to have a major influence on community composition. The composition of microbial inoculum from a previous filter could not be maintained through a cycle of culture, storage and re-culture. Furthermore, no significant proportion of the inoculum persisted in filter maturity, and no advantages in terms of time to filter maturation or final filter efficiency were evident. These results may explain why filtration is such an effective and robust water treatment and emphasize the need for further research on the mechanisms involved in pathogen elimination. 相似文献
115.
Amanda Black Ronald George McLaren Thomas Wilson Speir Lynne Clucas Leo Murtagh Condron 《Biology and Fertility of Soils》2014,50(4):685-694
The aim of this research was to identify and quantify gaps in currents methods and models for predicting the plant availability of selected nutrient and contaminant metals (Cu, Ni, Zn, Cd) in soil. This study investigated relationships between the relative solubility of Cu, Ni, Zn, and Cd determined by six extraction methods with short-term uptake by shoots and roots of wheat (Triticum aestivum). For Cu, Ni, and Cd, relationships between solubility and plant uptake were found to be different for shoots and roots, with Cu and Ni solubility being more closely correlated with root uptake compared with shoot uptake. Correlation coefficients for Cd concentrations in shoot and root tissue for all six solubility methods were poor (r 2?<?0.5), while corresponding results for Zn explained more than 50 % of shoot variation but less than 50 % of root variation. Soil Cu solubility explained up to 85 % of variation in root uptake compared with 42–55 % for shoot uptake. These results clearly demonstrated that purely chemical and passive diffusion mechanisms were inadequate predictors of Cd uptake by shoots and roots, together with Cu uptake by shoots. Thus further attempts at refining soil metal bioavailability assays based solely on chemical extraction without consideration of plant responses are unlikely to improve prediction of plant uptake. 相似文献
116.
Amanda Voros Ashley Dunnett Leo G. Leduc Mazen T. Saleh 《Veterinary microbiology》2009,138(3-4):384-389
Mycoplasma constitutes a unique group of bacteria best characterized as lacking peptidoglycan and having one of the smallest genomes of all free-living prokaryotes. Members of this group also represent important pathogens of humans, animals, and plants. Our understanding of the interaction between these pathogens and their hosts is limited, partly due to our inadequate knowledge of the secreted enzymes and virulence factors of these pathogens. Analysis of secreted proteins of mycoplasma has been hampered by their fastidious growth requirements where protein-rich growth supplements are required. Simple ultrafiltration of the complete medium through a 10 kDa cut-off membrane successfully removed virtually all of the polypeptides in the medium and supported the growth of Mycoplasma capricolum (type California kid). This modification (AM medium) exposed the activities of a number of enzymes produced by this bacterium during growth including; acid and alkaline phosphatase, gelatinase, and β-lactamase activities. We also show that the spent culture medium contained hemolysin activity. 相似文献
117.
We produce a detailed map of the perturbed surface density of neutral hydrogen in the outer Milky Way disk, demonstrating that the Galaxy is a non-axisymmetric multiarmed spiral. Spiral structure in the southern half of the Galaxy can be traced out to at least 25 kiloparsecs, implying a minimum radius for the gas disk. Overdensities in the surface density are coincident with regions of reduced gas thickness. The ratio of the surface density to the local median surface density is relatively constant along an arm. Logarithmic spirals can be fit to the arms with pitch angles of 20 degrees to 25 degrees . 相似文献
118.
Arbutus unedo L., the strawberry tree (Ericaceae family), is an evergreen shrub or small tree, typical of the Mediterranean fringe and climate. The aim of the present study was to evaluate the profile of the phenolic constituents of A. unedo fruits. Seven compounds were purified by Sephadex LH-20 column chromatography of the MeOH extract followed by HPLC and were characterized as arbutin, beta-D-glucogalline, gallic acid 4-O-beta-D-glucopyranoside, 3-O-galloylquinic acid, 5-O-galloylquinic acid, 3-O-galloylshikimic acid, and 5-O-galloylshikimic acid, by means of NMR and ESI-MS analyses. Moreover, LC-PDA-MS analysis of the red pigment of A. unedo fruits revealed the presence of three anthocyanins recognized as cyanidin 3-O-beta-D-galactopyranoside, delphinidin 3-O-beta-D-glucopyranoside, and cyanidin 3-O-beta-D-arabinopyranoside. These pigments were also quantified. 相似文献
119.
Kazazić SP Butković V Srzić D Klasinc L 《Journal of agricultural and food chemistry》2006,54(22):8391-8396
It was assumed that gas-phase ligation of metal monocations by flavonoids might provide some insight on the intrinsic antioxidant activity of the latter. Thus, the ligation of Fe+ and Cu+ ions by apigenin (1), luteolin (2), kaempferol (3), quercetin (4), myricetin (5), and naringenin (6) was investigated in the gas phase in a Fourier transform mass spectrometer (FTMS). Both of the metal ions, which were produced by laser desorption ionization (LDI), bind consecutively to two neutral flavonoid molecules either with or without the simultaneous loss of some part (H, CO, H2O) of the latter. The flavonoids are present in the instrument at steady concentrations. The formation of flavonoid positive ions by charge exchange is also a common observation but is accompanied, in some cases, by a loss of H, CO, or H2O fragments. The reaction paths and observed fragmentations are presented. The results are supported by DFT B3LYP calculations that indicate a preference for metal ion attack at C-ring and not at the B-ring site considered to be mainly responsible for flavonoid antioxidant activity. 相似文献
120.
Eileen Azevedo Santos Margarete Magalhães Souza Priscilla Patrocínio Abreu Leo Duc Haa Carson Schwartzhaupt da Conceição Ioná Santos Araújo Alexandre Pio Viana Alex-Alan Furtado de Almeida Jôsie Cloviane de Oliveira Freitas 《Euphytica》2012,184(3):389-399
Three new varieties of Passiflora hybrids were developed from crosses between P. sublanceolata J. M. MacDougal (ex P. palmeri var. sublanceolata Killip) versus P. foetida var. foetida L. Twenty putative hybrids were analyzed. Hybridizations were confirmed by RAPD and SSR markers. The RAPD primer UBC11 (5′-CCGGCCTTAC-3′)
generated informative bands. The SSR primer A08FP1 amplified species-specific fragments and heterozygote status was observed
with the two parent bands 240 and 280 bp. The molecular markers generated by primers were analyzed in terms of the presence
or absence of specific informative bands. The morphological characterization of the hybrids enabled their differentiation
into three groups, identified as: (1) Passiflora ‘Alva’, composed of five hybrid plants with white flowers, large corona, light purple filaments at base, white and purple/white
banding to apex; (2) P. ‘Aninha’, composed of six hybrid plants with pale pink flowers, corona filaments reddish/purple at base, white, purple/white
banding to apex; (3) P. ‘Priscilla’, composed of nine hybrid plants with white flowers, small corona, filaments dark purple at base, white and purple
to apex. The genomic homology of parent plants was verified by cytogenetic analysis. Both parents were 2n = 22. Meiosis was regular in genitors and hybrids. Aneuploidy was observed at hybrid groups P. ‘Alva’ and P. ‘Priscilla’ (2n = 20). Other authors had already observed the same number of chromosomes for some P. foetida genotypes. Obtaining valuable interspecific hybrids opens up new perspectives to offer opportunities in agribusiness for
producers and to arouse the interest of consumers into using passion flowers in the Brazilian ornamental plant market. 相似文献