The Geochemistry of Ombrotrophic Sphagnum Species Growing in Different Microhabitats Of Eight German and Belgian Peat Bogs and the Regional Atmospheric Deposition     

Heike Kempter  Burkhard Frenzel 《Water, air, and soil pollution》2007,184(1-4):29-48

Comparing today’s atmospheric deposition records with the elemental concentration and the net-uptake rates of ombrotrophic Sphagnum mosses from eight German and Belgian peat bogs revealed that most of all the quality and number of regularly obtained deposition monitoring data is not satisfactory. Moreover, it seems likely that the deposition rate, determined by Sphagnum mosses, does not reliably reflect the record of the total open field deposition indicated by the deposition monitoring data. The moss data, too, show a distinct spatial variability possibly because the geochemistry of peat mosses differs according to the annual growth in height, the total surface area and the surface roughness of the receptor ‘peat moss’ (special interception deposition). Increased Ti concentration values, for example, combined with a high annual growth rate in height at the hollow moss S. cuspidatum resulted in generally high Ti net-uptake rates and a high Ti inventory (total Ti in sample). We, therefore, suggest that productive Sphagnum species might be able to fix more Ti particles on their larger surface area than less productive species do. Moreover, the results demonstrate that for reliably calculating Sphagnum elemental net-uptake rates, as well as for all quantification of Sphagnum or peat geochemistry on a time and area basis, an accurate knowledge of the period the collected samples were exposed to atmospheric deposition is required. In particular, to do reliable reconstructions of past atmospheric deposition rates using peat deposits, further studies are needed to precisely specify the spatial variability in the geochemistry of living Sphagnum mosses.  相似文献   

Comparing 1H‐NMR imaging and relaxation mapping of German white asparagus from five different cultivation sites     

Marion I. Menzel  Ana‐Maria Oros‐Peusquens  Andreas Pohlmeier  N. Jon Shah  Ulrich Schurr  Heike U. Schneider 《植物养料与土壤学杂志》2007,170(1):24-38

Nuclear magnetic resonance imaging (MRI) and complementary analytical techniques were used to address the question whether white asparagus (Asparagus officinalis L.) from different cultivation sites in Germany can be distinguished on the basis of NMR relaxation times. Five locations with contrasting soil properties and composition within the two asparagus‐cultivation regions Rhineland and Lower Franconia were selected for this project. For the first time, entire asparagus plants in their authentic soil environment excavated directly from the original harvest site were imaged by the NMR technique. However, they could not be employed for determination of relaxation times of spears in situ, because of artifacts arising from soil properties. Instead, market‐ready asparagus spears and freshly prepared spear saps from the five locations were used to acquire MRI data sets with different (slow and fast) imaging methods and to compute spatially resolved distributions (maps) of T₁, T₂, and T₂* relaxation times. Comparison of the data for pith, vascular tissue, and peel of the spears yielded only marginal, if any, differences in T₁, T₂, and T₂* between the specimens from the five locations, which were not sufficient for an unambiguous region‐related distinction. More pronounced differences in T₁, T₂, and T₂* were visible for the spear saps, allowing a clear distinction between individual specimens for each of the two cultivation regions. The results are discussed in terms of an application potential for correlated NMR relaxation times of tissue saps for future geographic authentication of agricultural produces.  相似文献   

Studies on the metabolism of the plant lignans secoisolariciresinol and matairesinol   总被引：1，自引：0，他引：1  

Niemeyer HB  Honig DM  Kulling SE  Metzler M 《Journal of agricultural and food chemistry》2003,51(21):6317-6325

The plant lignans secoisolariciresinol and matairesinol occur in numerous foods such as oil seeds, whole grains, vegetables, and fruits. We have studied the hitherto unknown oxidative metabolism of secoisolariciresinol and matairesinol in hepatic microsomes from untreated and Aroclor 1254-induced Wistar rats and from humans. Five oxidative metabolites of secoisolariciresinol and 10 oxidative metabolites of matairesinol were detected in rat liver microsomes, and their chemical structures were elucidated. The pathways in the metabolism of both secoisolariciresinol and matairesinol included aliphatic and aromatic hydroxylation, whereas oxidative demethylation was only observed for matairesinol. Human hepatic microsomes were able to metabolize secoisolariciresinol whereas matairesinol was only poorly metabolized. This study clearly shows that secoisolariciresinol and matairesinol are substrates of cytochrome P450-mediated metabolism. However, from preliminary experiments with rats dosed orally with secoisolariciresinol and matairesinol, it appears that the intestinal absorption and subsequent oxidative metabolism of these plant lignans occur only to a very small extent due to the highly efficient conversion of secoisolariciresinol and matairesinol to the mammalian lignans enterodiol and enterolactone by the gut microflora.  相似文献   

Soil Surface Roughness as the Result of Aggregate Size Distribution 2. Report: Change in aggregate size classes caused by erosive rainfalls     

Stefan Gth  Heike Grk  Hans-Georg Frede 《植物养料与土壤学杂志》1995,158(1):37-41

The change of aggregate size classes caused by rainfall was examined using six different silly soils. The surface elevation profile lines were measured with a non-contact laser scanner with a measurement resolution of O.1 mm. The profile length ratio RZ and, based on the Fourier-analysis of the elevation profile line, the partial roughness were determined. The results demonstrate that in contrast to the profile length ratio RZ, the evaluation of partial roughness is an adequate method to determine the proportion of aggregate size fractions on total surface roughness. Furthermore, the results show that — independent of the soil texture and history — the smallest aggregate size classes are the most labile fractions. These small and labile aggregate size fractions are involved in the soil erosion process, especially in surface sealing. The extent of surface sealing, however, is influenced by soil texture, too.  相似文献   

Organic N forms of a subtropical Acrisol under no-till cropping systems as assessed by acid hydrolysis and solid-state NMR spectroscopy     

Jeferson Dieckow  João Mielniczuk  Heike Knicker  Cimélio Bayer  Deborah P. Dick  Ingrid Kögel-Knabner 《Biology and Fertility of Soils》2005,42(2):153-158

This study was conducted to investigate the influence of land-use systems (grassland and cropland) and of long-term no-till cropping systems [bare soil, oat/maize (O/M), pigeon pea+maize (P+M)] on the composition of organic N forms in a subtropical Acrisol. Soil samples collected from the 0- to 2.5-cm layer in the study area (Eldorado do Sul RS, Brazil) were submitted to acid hydrolysis and cross-polarization magic angle spinning (CPMAS) ¹⁵N and ¹³C nuclear magnetic resonance (NMR) spectroscopies. The legume-based cropping system P+M contained the highest contents of non-hydrolysable C and N, hydrolysable C and N, amino acid N and hydrolysed unknown N. The relative proportion of non-hydrolysable N was higher in bare soil (30.0%) and decreased incrementally in other treatments based on the total C and N contents. The amino acid N corresponded to an average of 37.2% of total N, and was not affected by land use and no-till cropping systems. The non-hydrolysable residue contained lower O-alkyl and higher aromatic C concentrations, as revealed by CPMAS ¹³C NMR spectroscopy, and higher C:N ratio than the bulk soil. No differences in the bulk soil organic matter composition could be detected among treatments, according to CPMAS ¹³C and ¹⁵N NMR spectra. In the non-hydrolysable fraction, grassland showed a lower concentration of aromatic and a higher concentration of alkyl C than other treatments. From CPMAS ¹⁵N NMR spectra, it could be concluded that amide N from peptide structures are the main organic N constituent. Amide structures are possibly protected through encapsulation into hydrophobic sites of organic matter and through organomineral interaction.  相似文献   

Members of the Kunitz-type protease inhibitor gene family of potato inhibit soluble tuber invertase in vitro   总被引：3，自引：0，他引：3  

Heike Glaczinski  A. Heibges  F. Salamini  Christiane Gebhardt 《Potato Research》2002,45(2-4):163-176

Summary A soluble proteinaceous invertase inhibitor was purified from tubers of cv. Provita. N-terminal amino acid sequencing of the purified protein indicated that the invertase inhibitor was a member of a family of small tuber proteins known as Kunitz-type protease inhibitors. The purified protein was completely inhibitory to soluble tuber invertase at quantities that did not inhibit trypsin. Based on amino acid sequence information of invertase inhibitor protein, seven candidate cDNA clones were identified in libraries of Provita and Saturna tubers. The candidate cDNA sequences differed from each other between 2% and 5%, having several non-conservative amino acid substitutions when compared with sequence related protease inhibitors. The results suggest invertase as an alternative target of tuber “protease” inhibitors.  相似文献   

Cellular uptake of carotenoid-loaded oil-in-water emulsions in colon carcinoma cells in vitro     

Ribeiro HS  Guerrero JM  Briviba K  Rechkemmer G  Schuchmann HP  Schubert H 《Journal of agricultural and food chemistry》2006,54(25):9366-9369

Oil-in-water emulsions allow the preparation of lipophilic compounds such as carotenoids in the liquid form. Here, the effect of a combination of some emulsifiers, such as two whey protein isolates (BiPro and BioZate), sucrose laurate (L-1695), and polyoxyethylene-20-sorbitan-monolaurate (Tween 20), on the stability of lycopene and astaxanthin in emulsions, droplet size, and cellular uptake of these carotenoids has been investigated. The degradation of lycopene was slightly more pronounced than that of astaxanthin in all emulsions. The concentration of lycopene and astaxanthin decreased by about 30% and 20%, respectively, in all emulsions after 3 weeks of storage in the dark at 4 degrees C. The kind of emulsifiers or their combinations have played an important role in the cellular uptake by the colon carcinoma cells line HT-29 and Caco-2.  相似文献   

Depletion, degradation, and recovery potential of estuaries and coastal seas   总被引：2，自引：0，他引：2  

Lotze HK  Lenihan HS  Bourque BJ  Bradbury RH  Cooke RG  Kay MC  Kidwell SM  Kirby MX  Peterson CH  Jackson JB 《Science (New York, N.Y.)》2006,312(5781):1806-1809

Estuarine and coastal transformation is as old as civilization yet has dramatically accelerated over the past 150 to 300 years. Reconstructed time lines, causes, and consequences of change in 12 once diverse and productive estuaries and coastal seas worldwide show similar patterns: Human impacts have depleted >90% of formerly important species, destroyed >65% of seagrass and wetland habitat, degraded water quality, and accelerated species invasions. Twentieth-century conservation efforts achieved partial recovery of upper trophic levels but have so far failed to restore former ecosystem structure and function. Our results provide detailed historical baselines and quantitative targets for ecosystem-based management and marine conservation.  相似文献