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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 147 (1992), S. 49-57 
    ISSN: 1573-5036
    Keywords: ammonium ; field ; kiwifruit ; 15N ; nitrogen fertilizer ; recovery ; soil nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The fate of 15N-labelled ammonium fertilizer applied once to six-year-old field-grown kiwifruit (Actinidia deliciosa ‘Hayward’) vines was measured over three years. The three main treatments were nitrogen (N) applied singularly at 100 or 200 kg N ha−1 in early spring (two weeks before bud burst) or split with 100 kg N ha−1 (unlabelled) in early spring and 100 kg N ha−1 (15N-labelled) ten weeks later. All N treatments were applied to vines with a history of either 50 or 200 kg N ha−1 yr−1. For three years after 15n application, components of the vines and soil (0–600 mm depth) were sampled at harvest in late autumn and the N and 15N contents determined. By the first harvest, all plant uptake of 15N had occurred and this represented 48–53% of the 15N applied. There was no significant effect of current N fertilizer treatment or of N history on 15N recovery by vines. Removal of 15N in harvested fruit was small at 5–6% in the first year and 8% over 3 years. After 2–3 years, most plant 15N occurred in the roots and this component declined only slowly over time. In contrast, there was a large temporal decline in 15N in above-ground plant components due to the annual ‘removal’ in leaf fall and pruning. An associated experiment showed that when 15N-labelled prunings and leaves were mulched and returned to the soil, only about 9% was recovered by plants within 2 years. Almost all remaining mulched material had been immobilised into the soil organic N. In all treatments, about 20% of the added 15N remained in soil at the first harvest. This was almost entirely in organic fractions (〈0.4% in inorganic N) and mostly in the surface 150-mm layer. The 15N content in soil changed little over time (from 20 to 17% between the first and third harvests respectively) and indicated that most of the N had been immobilised into stable humus forms.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 147 (1992), S. 59-68 
    ISSN: 1573-5036
    Keywords: kiwifruit ; 15N ; plant uptake ; remobilisation ; temporal changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Temporal changes in the nitrogen (N) and 15N content of various components of six-year-old kiwifruit (Actinidia deliciosa ‘Hayward’) vines which had received 15N-labelled ammonium fertilizer were measured. The fertilizer was applied singularly at 100 or 200 kg N ha−1 in early spring (two weeks before bud burst) or split with 100 kg N ha−1 (unlabelled) in early spring and 100 kg N ha−1 (15N-labelled) ten weeks later. All treatments were applied to vines with a history of either 50 or 200 kg N ha−1 yr−1. The N concentration of leaf and fruit tissue was generally lower in the 100 kg N ha−1 treatment than in the 200 kg N ha−1 treatments and this effect was greater than that of N fertilizer history. During the first 8 weeks after bud burst there was a rapid accumulation of N in leaves (ca. 80 kg N ha−1). Analysis of xylem sap at 4 weeks after bud burst revealed that about 60% of the N utilised for new growth was from remobilisation of N stored within the vines and about 40% from soil and fertilizer N. This was unaffected by rate of N application. Plant uptake of added 15N was rapid and almost complete within 10 weeks of application in either early spring or early summer. Initially, most 15N was present in the leaf and root components but these subsequently declined due to translocation into other components of the vine. The decline in leaf 15N coincided with an equivalent accumulation of 15N in the fruit. The 15N enrichment of the ‘annual’ components (leaves, fruit and current-season's shoots) was about twice that of the structural components (one-year-old shoots, cordon, stem and structural roots) during the first year after application. By the third year the 15N concentration of the annual components had declined to similar levels to that of the structural components. These changes were used to estimate the annual throughput of N from soil in vines which received no N fertilizer in years 2 and 3 at 50% of total above-ground N and only 7% in roots. This was equivalent to about 120 kg N ha−1 yr−1. Where fertilizer N (200 kg ha−1) was applied in year 2 the annual throughput of N from soil and fertilizer was about 170 kg N ha−1.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 61 (1937), S. 321-341 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 162 (1968), S. 157-175 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Ultrastructural and histochemical studies have revealed that the mouse colonic mucous membrane receives an extensive autonomic innervation. Nerve fibers enter the mucous membrane through the muscularis mucosae and ramify in the lamina propria where they were often seen in close proximity to smooth muscle cells. Other axons were seen accompanying blood vessels or passing along the basal aspect of the epithelium subjacent to the basement membrane; none were seen either entering the epithelium or within it.Several methods of fixation were employed in order to study their effects on intraaxonal vesicles. It was found that in tissue fixed in either glutaraldehyde in phosphate buffer, or in osmium tetroxide in phosphate buffer, the granular vesicles were better preserved than in tissue fixed in a chrome-osmium tetroxide mixture. The nerve fibers contained mainly agranular vesicles and large granular vesicles (600-1700 Å). Small granular vesicles (300-600 Å) usually associated with adrenergic nerves and specific green fluorescence indicative of catecholamines were only occasionally seen in the mucous membrane. Reserpine depleted the small granular vesicles and also abolished specific fluorescence.Ultrastructural studies showed that the large majority of nerve fibers were acetylcholinesterase positive.These findings indicate that the innervation of the colonic mucous membrane is predominantly cholinergic and that the adrenergic innervation is sparse.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1040-452X
    Keywords: EGF-like ligands ; Postnatal development ; RT-PCR ; Immunocytochemistry ; Immunoblotting ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Amphiregulin (Ar) and Cripto-1 (Cr-1) are growth promoting peptides that share amino acid sequence homology with epidermal growth factor (EGF). The present study examined Ar and Cr-1 mRNA and protein expression during various stages of C57BL/6 mouse mammary morphogenesis. Reverse transciption-polymerase chain reaction (RT-PCR) was used to detect transcripts for Ar and Cr-1 at all stages of mammary development. Immunocytochemical (ICC) localization demonstrated that in virgin 4-week to mature 12-week-old mouse fourth inguinal mammary gland, Ar and Cr-1 are expressed in the stromal cells, luminal epithelial cells, and myoepithelial cells of the branching ducts. Ar, and to lesser extent Cr-1, were also found in the epithelial cap cells and in the luminal epithelial cells of the advancing terminal end bud (TEB) from virgin 4-week and 6-week-old mice. Western blot analysis demonstrated that both Ar (28 and 26 kDa) and Cr-1 (90, 67, 56, and 21 kDa) proteins are expressed in virgin, 13.5 day midpregnant and in the 14 day lactating mammary gland. In addition, Ar and Cr-1 are associated with developing alveolar structures as determined by ICC. These results imply that together with EGF and transforming growth factor alpha (TGFα), Ar and Cr-1 may play salient roles as modifiers in the morphogenesis and differentiation of the mammary gland. © 1995 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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