Métabolisme glucidique de la racine de carotte cultivée (variété Nantaise demi-longue) au cours du cycle végétatif de la plante     

M. André Goris 《Plant foods for human nutrition (Dordrecht, Netherlands)》1969,18(4):307-330

Tuberisation of the carrot root is accompanied by a regular accumulation of soluble carbohydrates, greater in the case of saccharose than for glucose and fructose, so that very soon the reserve is principally disaccharide in nature. At first there is also slight formation of starch but it generally disappears by the end of autumn.The role of the tissues of the carrot root does not seem to be merely that of accumulating sugars provided by the leaves, but also of taking part to a certain degree in the synthesis of the saccharose that they contain. The formation of starch appears to be related to the osmotic pressure of the cells which rises with the increase of sugars.The ripening of carrots is not a well-defined physiological phenomenon. It may be regarded as corresponding to the time when the level of soluble sugars attains a constant value, even if the root continues to grow and consequently accumulate a further quantity of sugar.Development of the tuberous root and accumulation of sugars do not cease under the influence of climatic conditions, but depend on the date of sowing, as if they were limited by an ageing of the cells.Winter normally brings about a break in the development of the roots and a beginning of the utilisation of sugars. However, in plants sown late, the roots continue to grow and accumulate soluble sugars until mid-winter. A part of these sugars results from the hydrolysis of starch, but some are assimilated by the few green leaves that persist.In spring, vegetation is resumed after rehydration of tissues that were partly dehydrated during the accumulation of sugars. Formation of the flowering stalk is accompanied by the progressive disappearance of all sugars, which does not permit the attribution to any particular sugar of a specific biological role either in the formation of cell constituents or in the release of energy.It also appears that saccharose is not a merely passive form of reserve sugar, but that it is probably involved in certain reactions as a metabolite independent of the two reducing sugars.The period of flowering is independent of the time of sowing.In the tuberous root of the carrot, as in that of the sugar-beet and the rhizome of Jerusalem artichoke, the levels of ash and sugar vary inversely. The phenomenon has no biological significance, as claimed by certain authors, since the high rate of sugar accumulation affects the ratio only in a mathematical sense by reducing the relative percentage of ash.

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Zusammenfassung Die Wurzelbildung der Karotten wird begleitet von einer gleichmäßigen Zunahme löslicher Kohlenhydrate, wobei der Anteil der Saccharose stärker wächst als der der Glukose, so daß die Biose bald die Kohlenhydrat-Hauptreserve ist. Anfangs findet auch eine Bildung von Stärke statt, aber immer in sehr geringer Menge. Die Stärke verschwindet gegen Ende des Herbstes. Die Rolle des Karottengewebes scheint sich nicht nur auf die Anhäufung des durch die Blätter zugeführten Zuckers zu beschränken, sondern es nimmt auch in einem gewissen Maße Anteil an der Synthese der Saccharose, die im Gewebe enthalten ist. Die Bildung der Stärke scheint an die osmotische Spannung der Zelle, die sich immer durch den Beitrag des Zuckers erhöht, gebunden zu sein. Die Maturation der Karotte ist kein wohldefiniertes physiologisches Phänomen. Man kann sie als den Zeitpunkt beschreiben, in dem der Gehalt des löslichen Zuckers einen fast konstanten Wert erreicht, auch wenn die Speicherwurzel weiter wächst und dadurch neue Mengen an Kohlenhydraten anhäuft.Die Entwicklung der Wurzel und die Zunahme des Zuckers hört nicht unter dem Einfluß der klimatischen Bedingungen auf, sondern hängt ab vom Datum der Aussaat, als wäre sie begrenzt durch ein Älterwerden der Zellen.Im Winter stimmt normalerweise das Aufhören der Entwicklung der Wurzeln und der Beginn des Verbrauchs der Kohlenhydrate überein, während bei den Pflanzen, die später ausgesät werden, die Wurzeln noch wachsen und immer noch löslichen Zucker bis zur Mitte dieser Jahreszeit anhäufen. Ein Teil dieses Zuckers entstammt der Stärkehydrolyse, ein anderer bildet sich noch durch die chlorophyllische Assimilation, die in beschränktem Maße mittels einiger lebendig gebliebener Blätter fortdauert. Im Frühling beginnt die Wiederaufnahme des Wachstums mit einer Wiederhydratation der Wurzelgewebe, die während der Anhäufung der Kohlenhydrate teilweise ausgetrocknet waren. Die Bildung des blühenden Stengels wird begleitet von dem fortschreitenden Verschwinden sämtlicher Zucker, ohne daß man jedem eine biologische Rolle zuschreiben kann, sei es in der Bildung der Zellbestandteile oder in der Energieerzeugung. Es scheint auch, daß die Saccharose nicht nur als passive Reserve der reduzierenden Zucker angesehen werden darf, sondern daß sie wahrscheinlich wie ein Stoffwechselprodukt unabhängig von ihren beiden Bestandteilen in bestimmte Reaktionen eingreift.Die Blütezeit tritt unabhängig vom Zeitpunkt der Aussaat ein.In der Wurzel der Möhre sowie in der der roten Rübe und im Rhizom des Topinamburs verändern sich die Gehalte von Asche und Zucker umgekehrt. Dieses Phänomen hat keine biologische Bedeutung, wie bestimmte Autoren meinen, denn die starke Anhäufung der Zucker beeinflußt das Zucker-Asche-Verhältnis nur mathematisch gesehen infolge Herabdrücken des Prozentsatzes der Mineralstoffe.

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Improved diagnosis of powdery scab (Spongospora subterranea f.sp.subterranea) symptoms on potato tubers (Solanum tuberosum L.)     

Eisse G. De Haan  Gé w. Van Den Bovenkamp 《Potato Research》2005,48(1-2):1-14

Summary Based on visual inspection, discrimination between common scab (Streptomyces spp.) and powdery scab (Spongospora subterranea) can be difficult. Inspections are performed on unwashed samples, incidentally supported by microscopic examination. During 1994–1996 surveys were performed in The Netherlands on tubers with symptoms resembling common scab. Under microscopic assessment nearly all samples showed the presence of structures resembling cystosori (sporeballs) ofS. subterranea. At that time confirmation using alternative techniques was not possible. In 2003 research was undertaken to clarify the situation with respect to scab on potato tubers in The Netherlands. One hundred and eighteen scab samples were extensively tested forS. subterranea. All samples were digitally photographed, microscopically examinated and tested with real-time PCR and DAS-ELISA. Use of these modern methods resulted in a clear picture of symptoms that can be attributed toS. subterranea. A lot of scab samples with structures resembling cystosori could not be confirmed as contaminated withS. subterranea.  相似文献   

Effect of acetylsalicylic acid on soft rot produced byErwinia carotovora subsp.carotovora in potato tubers under greenhouse conditions     

María M. López  María José López-López  Rubén Martí  Javier Zamora  Jesús López-Sanchez  Ramona Beltra 《Potato Research》2001,44(2):197-206

Summary The efficiency of acetylsalicylic acid (ASA) in inducing localised acquired resistance against infection byErwinia carotovora subsp.carotovora was evaluated by treating potato tubers with ASA at three concentrations. Three days after treatments, tubers were inoculated withE. carotovora subsp.carotovora by wound inoculation or by irrigation with a bacterial suspension. Experiments were performed for two consecutive years. Statistical analysis revealed that treatment of tubers by immersion in ASA solutions at low concentrations induced a significant reduction in the soft rot incidence. Wounding of the tubers was the most effective inoculation method and ASA at concentration of 0.0125% (w/v), pH 7 was more efficient than at 0.025 or 0.05%. No phytotoxicity of such treatment was observed.  相似文献   

VARIATION IN SOIL ORGANIC CARBON AND NITROGEN STOCKS ALONG A TOPOSEQUENCE IN A TRADITIONAL MEDITERRANEAN OLIVE GROVE     

Beatriz Lozano‐García  Luis Parras‐Alcntara 《Land Degradation \u0026amp; Development》2014,25(3):297-304

The impact of the topographical position on soil properties was evaluated in an olive grove with traditional tillage. Three topographical positions: summit, backslope and toeslope were chosen for evaluation. The soil samples were taken from four soil sections of 0·25 m (0–1 m). The soil organic carbon (SOC) and N content increased along the downslope direction (5·5, 6·5 and 7·1 g C kg⁻¹ and 0·3, 0·8 and 0·9 g N kg⁻¹ in the surface layer in the summit, backslope and toeslope respectively) as well as SOC and N stocks, considering the two first soil sections. In addition, there was movement of the most erodible textural fraction (silt). However, the total SOC stock (refer to 1 m of depth) did not vary with respect to the topographical position, but the total N stock (refer to 1 m of depth) varied significantly. These increases were due to erosion processes that occur along the toposequence, leading to organic matter transfers from the summit to the toeslope. All the stratification ratios calculated were lower than 2, indicating the low quality of the soils. Therefore, alternative management techniques that avoid soil erosion must be considered in olive grove in order to increase the soil quality and fertility. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Evaluation of preflooding effects on iron extractability and phytoavailability in highly calcareous soil in containers          下载免费PDF全文

Inmaculada Sánchez‐Alcalá  María del Carmen del Campillo  Vidal Barrón  José Torrent 《植物养料与土壤学杂志》2014,177(2):150-158

Previous pot cropping and laboratory incubation experiments were consistent with field observations showing that temporary flooding before cropping can increase the availability of soil Fe to plants. To study the effect of temporary flooding on changes in soil Fe phytoavailability we used 24 highly calcareous, Fe chlorosis–inducing soils to carry out a pot experiment where peanut and chickpea were successively grown after flooding for 30 d. At the end of the cropping experiment, the preflooded soil samples exhibited higher concentrations of acid oxalate‐, citrate/ascorbate‐ and diethylenetriaminepentacetic acid (DTPA)–extractable Fe (Fe_ox, Fe_ca, and Fe_DTPA, respectively) than the control (nonflooded) samples. Also, Fe_ox and Fe_ca exhibited no change by effect of reflooding of the cropped soils or three wetting–drying cycles in freeze‐dried slurries of soils previously incubated anaerobically for several weeks. Leaf chlorophyll concentration (LCC) in both peanut and chickpea was greatly increased by preflooding. The best predictor for LCC was Fe_ox, followed by Fe_ca and Fe_DTPA. The LCC–soil Fe relationships found suggest that the Fe species extracted by oxalate and citrate/ascorbate from preflooded soils were more phytoavailable than those extracted from control soils. However, the increased phytoavailability of extractable Fe forms was seemingly limited to the first crop (peanut). Flooding dramatically increased Fe_DTPA; however, high Fe_DTPA levels did not result in high LCC values, particularly in the second crop. Therefore, this test is a poor predictor of the severity of Fe chlorosis in preflooded soils.  相似文献   

Physico‐chemical characterization of humic‐metal‐phosphate complexes and their potential application to the manufacture of new types of phosphate‐based fertilizers          下载免费PDF全文

Oscar Urrutia  Javier Erro  Inaki Guardado  Sara San Francisco  Marcos Mandado  Roberto Baigorri  Jean Claude Yvin  José Ma Garcia‐Mina 《植物养料与土壤学杂志》2014,177(2):128-136

The aim of this review is to describe the main physicochemical characteristics of diverse types of humic‐metal‐phosphate acid complexes. The effects of these complexes on phosphorus (P) fixation in soils with different pH values and physicochemical features and on plant phosphorus uptake are also discussed. Humic‐metal‐phosphate complexes have apparent stability constants in the same range as those of metal‐humic complexes, in solutions with diverse pH and ionic‐strength values. Likewise, the molecular‐size distribution of humic‐metal‐phosphate complexes as a function of pH is similar to that of potassium or sodium humates and metal‐humic complexes. Humic‐metal‐phosphate complexes are able to decrease phosphate fixation in soils and increase plant growth and phosphate uptake. Phosphorus fertilizers containing humic‐metal‐phosphate complexes proved to be efficient to improve plant growth and P uptake with respect to conventional fertilizers such as single superphosphate. The values of parameters related to plant phosphorus‐utilization efficiency (PUt E) suggest that the regulation of root acquisition of phosphate from these complexes could involve the interregulation of a system for the optimization of metabolic P utilization in the shoot and another system involving stress responses of roots under phosphorus deficiency.  相似文献   

Spatial variation of trace elements in the peri-urban soil of Madrid     

Antonio Vázquez de la Cueva  Ben P. Marchant  José Ramón Quintana  Ana de Santiago  Antonio López Lafuente  Richard Webster 《Journal of Soils and Sediments》2014,14(1):78-88

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Spectral fingerprinting: characterizing suspended sediment sources by the use of VNIR-SWIR spectral information     

Arlena Brosinsky  Saskia Foerster  Karl Segl  José Andrés López-Tarazón  Gemma Piqué  Axel Bronstert 《Journal of Soils and Sediments》2014,14(12):1965-1981

Purpose

Knowledge of sediment sources is a prerequisite for sustainable management practices and may furthermore improve our understanding of water and sediment fluxes. Investigations have shown that a number of characteristic soil properties can be used as “fingerprints” to trace back the sources of river sediments. Spectral properties have recently been successfully used as such characteristics in fingerprinting studies. Despite being less labour-intensive than geochemical analyses, for example, spectroscopy allows measurements of small amounts of sediment material (>60 mg), thus enabling inexpensive analyses even of intra-event variability. The focus of this study is on the examination of spectral properties of fluvial sediment samples to detect changes in source contributions, both between and within individual flood events.

Materials and methods

Sediment samples from the following three different origins were collected in the Isábena catchment (445 km²) in the central Spanish Pyrenees: (1) soil samples from the main potential source areas, (2) stored fine sediment from the channel bed once each season in 2011 and (3) suspended sediment samples during four flood events in autumn 2011 and spring 2012 at the catchment outlet as well as at several subcatchment outlets. All samples were dried and measured for spectral properties in the laboratory using an ASD spectroradiometer. Colour parameters and physically based features (e.g. organic carbon, iron oxide and clay content) were calculated from the spectra. Principal component analyses (PCA) were applied to all three types of samples to determine natural clustering of samples, and a mixing model was applied to determine source contributions.

Results and discussion

We found that fine sediment stored in the river bed seems to be mainly influenced by grain size and seasonal variability, while sampling location—and thus the effect of individual tributaries or subcatchments—seem to be of minor importance. Suspended sediment sources were found to vary between, as well as within, flood events; although badlands were always the major source. Forests and grasslands contributed little (<10 %), and other sources (not further determinable) contributed up to 40 %. The analyses further suggested that sediment sources differ among the subcatchments and that subcatchments comprising relatively large proportions of badlands contributed most to the four flood events analyzed.

Conclusions

Spectral fingerprints provide a rapid and cost-efficient alternative to conventional fingerprint properties. However, a combination of spectral and conventional fingerprint properties could potentially permit discrimination of a larger number of source types.  相似文献   

Clinical and histopathologic characterization of a central and peripheral axonopathy in Rouge-des-prés (Maine Anjou) calves     

Timsit E  Albaric O  Colle MA  Costiou P  Cesbron N  Bareille N  Assié S 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2011,25(2):386-392

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Mesenteric lymph node cells from neonates present a prominent IL-12 response to CpG oligodeoxynucleotide via an IL-15 feedback loop of amplification     

Ferret-Bernard S  Lacroix-Lamandé S  Remot A  Metton C  Bernardet N  Charley B  Drouet F  Laurent F 《Veterinary research》2011,42(1):19

ABSTRACT: At birth, the immune system is still in development making neonates more susceptible to infections. The recognition of microbial ligands is a key step in the initiation of immune responses. It can be mimicked to stimulate the immune system by the use of synthetic ligands recognising pattern recognition receptors. In human and mouse, it has been found that neonatal cytokine responses to toll-like receptor (TLR) ligands differ in many ways from those of adults but the relevant studies have been limited to cord blood and spleen cells. In this study, we compared the responses in neonate and adult sheep to CpG oligodeoxynucleotides (ODN), a TLR9 ligand, in both a mucosal and a systemic organ. We observed that in response to CpG-ODN more IL-12 was produced by neonatal than adult sheep cells from mesenteric lymph nodes (MLN) and spleen. This higher IL-12 response was limited to the first 20 days after birth for MLN cells but persisted for a longer period for spleen cells. The major IL-12-producing cells were identified as CD14+CD11b+. These cells were poor producers of IL-12 in response to direct stimulation with CpG-ODN and required the cooperation of other MLN cells. The difference in response to CpG-ODN between neonates and adults can be attributed to both a higher proportion of CD14+CD11b+ cells in neonate lambs and their higher capacity to produce IL-15. The IL-15 increases IL-12 production by an amplifying feedback loop involving CD40.  相似文献