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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 70 (1987), S. 0 
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: In the sugar beet plant (Beta vulgaris L. ssp. altissima) the vascular bundles of old leaves lead to the center and those of young leaves to the periphery of the storage root. Whether the flux of assimilates follows these anatomical routes was tested by applying 14CO2 for 4 h to either an old (10th) or a young (20th) leaf in intact sugar beet plants. Four-month-old plants, which had about 30 leaves, were used in the experiment. The 14C distribution in the storage root was measured by autoradiography and counting in about 20 cross and longitudinal sections per root.About 37% of assimilated 14C from an old leaf and 23% from a young leaf were exported within 24 h. Although some 14C moved into younger leaves, most was exported into the storage root. During its rapid movement towards the root tip, which took place perferentially in the orthostichon belonging to the [14C]-treated leaf, the label spread laterally.The autoradiograms indicate that the distribution of assimilates within the storage root is roughly determined by the course of the vascular bundles extending from the source leaf. The fine distribution, however, seems to be controlled by sucrose gradients between storage cells.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 57 (1970), S. 40-40 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 5 (1987), S. 181-187 
    ISSN: 1432-0789
    Keywords: Denitrification ; Rhizosphere ; Bulk density ; Water tension ; Acetylene inhibition method ; Triticum vulgare
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Pot experiments were carried out to study the influence of bulk density (D b), soil water tension (pF) and presence of plants (spring wheat) on denitrification in a low-humus Bt-horizon of a udalf. Pots of only 5-cm depth were found to be most suitable for the experiments when using the acetylene inhibition method. Almost homogeneous soil compaction between 1.1 and 1.6g soil cm−3 was achieved by a Proctor tamper. Water tensions were adjusted by means of ceramic plates on which negative pressure was applied. No denitrification was detected in unplanted pots. With planted pots and increasing bulk density denitrification increased more in pots with 14-day-old plants than in pots with 7-day-old plants. With 14-day-old plants N2O emission pot−1 increased steadily from 2 μmol at D b 1.1 to 8 μmol at D b 1.6, when soil moisture was adjusted to pF 1.5, although root growth was impaired by higher bulk density. From an experiment with different bulk densities and water tensions it could be deduced that the air-filled porosity ultimately determined the rate of denitrification. When low water tension was applied for a longer period, water tension had an overriding effect on total denitrification. Denitrification intensity, however, i.e. the amount of N2O g−1 root fresh weight, was highest when low water tension was accompanied by high bulk density. The results suggest that the increase in denitrification intensity at oxygen stress is partly due to higher root exudation.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 6 (1988), S. 188-188 
    ISSN: 1432-0789
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-5036
    Keywords: cell sap ; chloride ; fertilizer ; potassium ; potato ; Solanum tuberosum L. ; solute potential ; source: sink ; sulphate ; tuber
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In pot experiments with Solanum tuberosum L. (cv Saturna) the application of KCl as compared to K2SO4 delayed tuber development. The solute composition of leaves of the KCl treated plants was significantly lower in K+ and NO3 -, but higher in Mg2+, Ca2+ and Cl-. Since the solute potential in the KCl treated plants was more negative and associated with a higher water content, a higher turgor pressure can be assumed. This could explain the enhanced shoot growth observed with KCl. Application of K2SO4, on the other hand, accelerated the development of tubers. This might result from a less competitive shoot sink in K2SO4 treated plants and a stimulated phloem loading and translocation of assimilates by higher concentrations of leaf-K.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 53 (1979), S. 445-453 
    ISSN: 1573-5036
    Keywords: Alluvial soils ; Ammonium ; Amino acids ; Chernozem ; Clay minerals ; Electroultrafiltration ; EUF Nitrate ; Nmin ; N release ; N reserves
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The determination of N fractions in the soil by means of electro-ultrafiltration (EUF) is described. The results can be summarized as follows: 1) For aqueous soils suspension the direction of NH4 + and NO3 − migration in an electric field is determined by electrical charge and water flow. Therefore the filtrates obtained at both the cathode and anode can be mixed for subsequent analysis for NH4−N and NO3−N. In order to avoid N losses the volatile NH3 is recovered in 1N HCl solution. 2) Considerable amounts of NH4−N and NO3−N as well as low-molecular organic N compounds can be determined by EUF in soil samples taken from June to September. The readily available N is extracted by EUF at 20°C and 200 V, while determinations at 80°C and 400 V also give information on N release from reserves. 3) It was demonstrated with soils from long term N and K fertilizer experiments that the EUF−NO3 contents reflect the N accumulation in the soil due to N fertilization or plant residues. In clayrich soils the EUF−NH4 contents give information on the release of fixed NH4. Moreover EUF−NH4 also gives information on N from readily mineralizable organic compounds. The EUF procedure gives improved insight into the N dynamics of a site and this should serve as a basis for N-fertilizer recommendations.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 83 (1985), S. 143-149 
    ISSN: 1573-5036
    Keywords: EUF-K content ; K uptake ; Sugar yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In field experiments with varying K fertilization (1981 and 1982) changes in EUF-K contents were studied in deep loess soils of Southern Lower Saxony under sugar beet. A significant positive linear relationship was found between EUF-K contents at 20°C and 200 V (≤15 mA) of the topsoils and quantities of K absorbed by sugar beet in both years. The corresponding regression lines for 1981 and 1982 are almost parallel, the only difference being the yield level which was higher in 1982. The relationship between EUF-K contents at 20°C of topsoils and sugar yields showed the same parallelism for the two years. Not much increase in sugar yield was found at EUF-K contents over 12 mg/100 g soil at EUF-K 80°C/EUF-K 20°C ratios between 0.5 and 0.7. To attain a sugar yield of 10 t/ha an EUF-K 20°C value of at least 12 mg/100 g soil is required for these deep soils at the beginning of the K uptake period. This finding confirms experiences gained over an 8-year period at the Tulln Sugar Factory (Austria) with fertilizer recommendations based on EUF.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 83 (1985), S. 21-37 
    ISSN: 1573-5036
    Keywords: Fertilizer recommendation ; Interaction of nutrients ; Nutrient requirement ; Nutrient transport ; Q/I relationship ; Rhizosphere ; Root system ; Soil analysis ; Soil solution ; Yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Routine soil-testing methods are excellent tools for monitoring soil fertility. However, if used for predicting optimal fertilizer requirements they will frequently fail. This applies especially to soils having high fertility levels needed for commercial farming with many other factors affecting plant growth. Explanatory examples are given for crop-specific nutrient requirements, for nutrient transport within the rhizosphere, for nutrient supply from subsoil and for interactions of nutrients. Soil-testing methods must become more comprehensive with regard to the number of nutrients analysed and to the rates of nutrient supply and the magnitudes of nutrient reserves.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 83 (1985), S. 47-53 
    ISSN: 1573-5036
    Keywords: EUF-N fractions ; Nitrification ; NO3 leaching ; Slurry-N ; Dicyandiamide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Increasing quantities of slurry (30, 60 and 90 m3/ha as well as 60 m3/ha + DIDIN) were applied to two sandy soils both in September and in December 1982. During the 1982/83 winter EUF-N was determined in soil horizons (0–30 cm, 30–60 and 60–90 cm). EUF-NO3 and EUF-Norg clearly reflected the different quantities of slurry applied. The retarding effect of DIDIN on nitrification could also be demonstrated by means of the EUF-N contents. Due to the mild and humid climate prevailing in the winter of 1982/83 slurry-NO3 of the September applications had obviously been leached out of the 0–60 cm soil layer in all treatments by February and even out of the 60–90 cm layer by March 24. Translocation of NO3 was also observed for slurry applied in December. But in this case on March 24 the EUF-NO3 contents in the 60–90 cm layer still reflected the quantities of slurry applied four months earlier. After slurry application the EUF-Norg fraction of a soil initially consists mainly of NH 4 + which is rapidly oxidized to NO3 and transferred in this form to deeper layers. As a consequence a rapid decline in EUF-Norg fraction is observed. It could therefore be expedient to consider the Norg and EUF-NH 4 + fractions separately when slurry applications are concerned.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 113 (1989), S. 205-211 
    ISSN: 1573-5036
    Keywords: chemical extractants ; sulfate ; S-uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Sulfur availability in twenty selected surface soils (0–22 cm), which varied in both physical and chemical properties and sampled under cultivated and uncultivated management in the various ecological zones of Ghana, was studied. Texture varied from coarse sand to clay, with 16–85% sand and 10–51% clay. Organic C varied from 0.45 to 2.24% and total N from 0.034 to 0.215%; soil pH (0.01M CaCl2) from 3.69 to 7.43 and total S from 44 to 273 ppm. Inorganic sulfate formed 2.3 to 14.8% of the total S, HI-reducible S 4.4 to 28.2, C-bonded S 4.4 to 28.2 and unidentified organic S 12.7 to 63.2%. Sulfur availability was assessed by chemical extraction methods and electroultrafiltration technique as follows: (i) extraction with Ca(H2PO4)2·H2O solution containing 500 ppm P, (ii) extraction with 0.1M LiCl and (iii) electroultrafiltration (EUF) at 80°C, 400 V for 10 min and also on seven of the soils the standard EUF fractionation procedure of Neméth. Ca(H2PO4)2-extractable S was not significantly correlated with LiCl-extractable S nor with any of the EUF values. LiCl-extractable S was not significantly correlated with sulfate extractable by and EUF−1+2+3 fractions (r=0.911**). Dry matter yield of oat seedlings and EUF−1+2+3 fractions (r=0.911**). Dry matter yield of oat seedlings was not correlated with any of the availability indexes. Total S uptake was significantly correlated with LiCl-extractable S (r=0.629** without S and 0.729** with S applied) and with EUF-80°C, 400 V/10 min (r=0.561**), EUF-1 (r=0.953***) and EUF-2 (r=0.912**). On all the soils, more S was taken up by oat plants than could be accounted for by the inorganic S and S mineralized from organic S during an incubation period of 4 weeks.
    Type of Medium: Electronic Resource
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