Metabolic response of Medicago sativa to severe nutrient imbalances and disturbances under field conditions          下载免费PDF全文

Thomas Fester  Ines Merbach  Elke Schulz  Claus Härtig 《植物养料与土壤学杂志》2014,177(2):245-259

Our experiments were focused on the metabolic footprint of mineral‐nutrient availability under field conditions. While there are multiple factors potentially blurring such footprints, we hypothesized that physiological and metabolic adaptations of established plants are particularly important mechanisms under field conditions. To study respective differences between young and established plants and to study the impact of disturbances on the adaptive capacity of established plants, we analyzed Medicago sativa plants of different age from plots with marked differences in the levels of soil mineral nutrients established in a long‐term fertilization experiment. Gas chromatography–mass spectrometry was used to determine metabolite profiles of sink and source leaves of plants in an early state of development (“young plants”), just before the first harvest (“established plants”), and a short time after the second harvest (“regrowing plants”). Metabolite profiles from young plants were markedly responsive to soil mineral nutrients and resembled respective profiles from controlled conditions, demonstrating that overall variability of growth and sampling conditions had relatively little importance for the metabolite profiles recorded. In the case of established plants, however, we observed only little impact of availability of mineral nutrients on metabolite profiles. This low metabolic responsiveness of plants was partially lost after severe disturbances (removal of the plant shoot). Metabolite profiling, in summary, is able to detect a metabolic footprint of mineral‐nutrient availability in young plants under field conditions and may provide information about the ability of older plants to partially uncouple their metabolism from the environment. In addition, it is also possible to determine the impact of disturbances on this ability of the plant organism.  相似文献   

Phosphorus uptake by cowpea plants from sparingly available or soluble sources as affected by nitrogen form and arbuscular‐mycorrhiza‐fungal inoculation     

Benard Ngwene  Eckhard George  Winfried Claussen  Elke Neumann 《植物养料与土壤学杂志》2010,173(3):353-359

In most plant species, nutrient uptake is facilitated upon root association with symbiotic arbuscular mycorrhizal (AM) fungi. The aim of the present experiment was to test how the form in which nitrogen (N) is supplied to the growth medium affects substrate pH, AM development, and contribution of the symbiosis to phosphorus (P) uptake from sparingly available or soluble resources. Cowpea (Vigna unguiculata L. Walp) plants inoculated or noninoculated with AM fungi (Glomus sp.) were grown in pots with a sand substrate supplied with nutrient solution. The nutrient solution was prepared either with a high or a low concentration of soluble P, and NO ‐N : NH ‐N ratios of 9:1 or 5:5. The substrate supplied with low‐P nutrient solution was either or not additionally amended with ground rock phosphate. Despite a high level of root colonization, AM fungi used in the present study did not appear to increase plant availability of rock phosphate. It cannot be excluded that the ability of AM root systems to acquire P from sparingly available resources differs depending on the plant and fungal genotypes or environmental conditions. The absence from the growth substrate of P‐solubilizing microorganisms able to associate with AM mycelia might also have been a reason for this observation in our study. Increased supply of NH relative to NO improved plant P availability from rock phosphate, but also had a negative effect on the extent of AM‐fungal root colonization, irrespective of the plant P‐nutritional status. Whether increasing levels of NH can also negatively affect the functioning of the AM symbiosis in terms of plant element uptake, pathogen protection or soil‐structure stabilization deserves further investigation.  相似文献   

Redistributing work in aging Europe     

Vaupel JW  Loichinger E 《Science (New York, N.Y.)》2006,312(5782):1911-1913

As Europe ages, the proportion of people who work will decline unless older individuals remain in the labor force. Such reform could be part of a more general redistribution of work. If a greater share of the population worked, then the average number of hours worked per week could be reduced. This could particularly help younger people and increase Europe's low birth rates. The challenges facing Germany, Europe's most populous country, are highlighted, but statistics are also given for five other European countries and, for comparison, the United States. Social science research is needed to provide policy-relevant knowledge about life-course options.  相似文献   

Engineering yeast transcription machinery for improved ethanol tolerance and production     

Alper H  Moxley J  Nevoigt E  Fink GR  Stephanopoulos G 《Science (New York, N.Y.)》2006,314(5805):1565-1568

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Polyphenols are intensively metabolized in the human gastrointestinal tract after apple juice consumption   总被引：1，自引：0，他引：1  

Kahle K  Huemmer W  Kempf M  Scheppach W  Erk T  Richling E 《Journal of agricultural and food chemistry》2007,55(26):10605-10614

Polyphenols are secondary plant compounds showing anticarcinogenic effects both in vitro and in animal experiments and may thus reduce the risk of colorectal cancer in man. The identification of polyphenol metabolites formed via their passage through the small intestine of healthy ileostomy subjects after apple juice consumption is presented. Identification and quantification of polyphenols and their metabolites were performed using HPLC-DAD as well as HPLC-ESI-MS/MS. Total procyanidin content (TPA) was measured, and additionally the mean degree of polymerization (DPm) of the procyanidins was determined in the apple juice and ileostomy effluents. As products of polyphenol metabolism, D-(-)-quinic acid and methyl esters of caffeic acid and p-coumaric acid are liberated from the corresponding hydroxycinnamic acid esters. 1-Caffeoylquinic acid and 3-caffeoylquinic acid were determined as products of isomerization. Phloretin 2'-O-glucoside (phloridzin) and phloretin 2'-O-xyloglucoside were metabolized into the corresponding aglycons phloretin and phloretin 2'-O-glucuronide and all were found in the ileostomy effluent. Ninety percent of the consumed procyanidins were recovered in the ileostomy effluent and therefore would reach the colon under physiologic circumstances. The DP m was reduced (DP m of apple juice=5.7) and varied depending on the time point of excretion. The gastrointestinal passage seems to play an important role in the colonic availability of apple polyphenols.  相似文献   

The Use of Ovule Culture in Reciprocal Hybridization between B. campestris L. and B. oleracea L.     

E. Diederichsen  M. D. Sacristan 《Plant Breeding》1994,113(1):79-82

Ovule culture was used to overcome postzygotic interspecific incompatibility in reciprocal crosses between Brassica campestris and B. oleracea. Hybrid plants were obtained from 82 % of all reciprocal pollinations, representing 91 % of the attempted combinations. Comparisons of the embryo culture and the ovule culture indicated a significantly higher germination rate after ovule culture.  相似文献   

Seed colour, seed weight and seed oil content in Linum usitatissimum accessions held by Plant Gene Resources of Canada     

A. Diederichsen    J. P. Raney 《Plant Breeding》2006,125(4):372-377

The purpose of this study was to investigate variation of and relationships among seed colour, seed weight and seed oil content in cultivated flax (Linum usitatissimum L. ssp. usitatissimum). Seed from 2934 flax genebank accessions recently grown at Saskatoon, SK, Canada, originating from 72 countries was used to describe the variation of the seed characters. The dominant seed colour of the accessions was medium brown (2730 accessions, 93.0%), followed by yellow (126 accessions, 4.3%). Based on single observations for all accessions, the overall mean and standard deviation was 5.95 ± 1.22 mg/seed for seed weight and 38.3 ± 1.74% for oil concentration. Within three infraspecific groups of flax, seed weight, oil concentration and oil amount per seed increased in the following order: fibre flax (convar. elongatum), intermediate flax (convar. usitatissimum), large‐seeded flax (convar. mediterraneum). The world collection exceeded the range of variation of seed weight and oil concentration found in 52 North American cultivars. There was a weak, positive association of higher oil concentration with higher seed weight (r² = 0.32; P < 0.001). Yellow‐seeded flax had a higher seed weight (6.31 vs. 5.92 mg/seed) and oil concentration (39.4% vs. 38.3%) than brown‐seeded flax. There was a tendency for yellow seed colour to be associated with higher oil concentration in all seed weight classes. The results suggested that indirect selection for increased seed oil concentration in flax is possible by selection for higher seed weight and yellow seed colour.  相似文献   

Comparison of genetic diversity of flax (Linum usitatissimum L.) between Canadian cultivars and a world collection     

A. Diederichsen   《Plant Breeding》2001,120(4):360-362

This study reports results of phenotypic measurements of genetic diversity in the world collection of flax maintained by Plant Gene Resources of Canada (PGRC) and compares the range of diversity in the world collection with the diversity observed in 19 Canadian registered flax cultivars. Morphological and seed‐oil characters were used to describe the phenotypic diversity in 2331 flax accessions. The plants were grown by PGRC at Saskatoon, Saskatchewan, Canada, in 1998 and 1999. The comparison between the Canadian cultivars and the world collection was based on single characters, as well as on character complexes by application of an existing intraspecific classification for the species. Considering single quantitative or qualitative character expressions, the Canadian cultivars represented a wide range in diversity for the species. The variation of characters Canadian plant breeders have selected for (e.g. plant height, seed weight, seed colour, petal colour, oil content) was reduced further than those characters not focused on by plant breeders (e.g. dotting of the sepals, style colour, ciliation of capsule septa, oil quality characters). A comparison of diversity based on the intraspecific classification proposed for flax by Kulpa and Danert, who described 28 botanical varieties, showed that all Canadian cultivars belong to two botanical varieties. This study demonstrates the usefulness of agrobotanical characterization of genebank collections for plant breeding and illustrates the application of the traditional method of intraspecific classification for comparison of gene pools.  相似文献   

Multivariate analysis of FTIR and ion chromatographic data for the quality control of tequila     

Lachenmeier DW  Richling E  López MG  Frank W  Schreier P 《Journal of agricultural and food chemistry》2005,53(6):2151-2157

Principal component analysis (PCA) was applied to the chromatographic and spectroscopic data of authentic Mexican tequilas (n = 14) and commercially available samples purchased in Mexico and Germany (n = 24). The scores scatter plot of the first two principal components (PC) of the anions chloride, nitrate, sulfate, acetate, and oxalate accounting for 78% of the variability allowed a classification between tequilas bottled in Mexico and overseas; however, no discrimination between tequila categories was possible. Mexican products had a significantly (p = 0.0014) lower inorganic anion concentration (range = 1.5-5.1 mg/L; mean = 2.5 mg/L) than the products bottled in the importing countries (range = 3.3-62.6 mg/L; mean = 26.3 mg/L). FTIR allowed a rapid screening of density and ethanol as well as the volatile compounds methanol, ethyl acetate, propanol-1, isobutanol, and 2-/3-methyl-1-butanol using partial least-squares regression (precisions = 5.3-29.3%). Using PCA of the volatile compounds, a differentiation between tequila derived from "100% agave" (Agave tequilana Weber var. azul, Agavaceae) and tequila produced with other fermentable sugars ("mixed"tequila) was possible. The first two PCs describe 89% of the total variability of the data. Methanol and isobutanol influenced the variability in PC1, which led to discrimination. The concentrations of methanol and isobutanol were significantly higher (methanol, p = 0.004; isobutanol, p = 0.005) in the 100% agave (methanol, 297.9 +/- 49.5; isobutanol, 251.3 +/- 34.9) than in the mixed tequilas (methanol, 197.8 +/- 118.5; isobutanol, 151.4 +/- 52.8).  相似文献   

Determination of the 2H/1H and 15N/14N ratios of Alkylpyrazines from coffee beans (Coffea arabica L. and Coffea canephoravar. robusta) by isotope ratio mass spectrometry     

Richling E  Preston C  Kavvadias D  Kahle K  Heppel C  Hummel S  König T  Schreier P 《Journal of agricultural and food chemistry》2005,53(20):7925-7930

The delta15N(AIR) and delta2H(VSMOW) data for several alkylpyrazines formed during the roasting process of coffee are reported. Samples of commercially available roasted (n = 9) as well as self-roasted (n = 8) coffee beans (Coffea arabica L. and Coffea canephora var. robusta) of different origins were investigated. By use of extracts prepared by simultaneous distillation extraction (SDE) and subsequently fractionated by liquid chromatography on silica gel, on-line capillary gas chromatography-isotope ratio mass spectrometry was employed in the combustion (C) and pyrolysis (P) modes (HRGC-C/P-IRMS) to determine the delta15N(AIR) and delta2H(VSMOW) values, respectively. In addition to the constituents of coffee beans, data for commercial synthetic alkylpyrazines and substances declared to be "natural" were determined. The delta15N(AIR) data for coffee alkylpyrazines under study-2-ethyl-5-methylpyrazine (1) and 2-ethyl-6-methylpyrazine (2) (measured as sum 1/2), 2-ethyl-3-methylpyrazine (3), 2-methylpyrazine (4), 2,5-dimethylpyrazine (5) and 2,6-dimethylpyrazine (6) (measured as sum 5/6), and 2,3-dimethylpyrazine (7), as well as 2,3,5-trimethylpyrazine (8)-varied in the range from +8.3 to -10.2 per thousand, thus revealing their biogeneration from amino acids (delta15N(AIR) ranging from +8 per thousand to -10 per thousand). The delta2H(VSMOW) values were determined in the range from -5 per thousand to -127 per thousand. Owing to the analytical differentiation observed between coffee alkylpyrazines and synthetic/"natural" samples of 3, 4, and 7, authenticity assessment of coffee-flavored products seems to be promising, provided that extended data will be available in the future. In the literature, there were no IRMS data available for the alkylpyrazines (1-8) under study.  相似文献