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  • 11
    Electronic Resource
    Electronic Resource
    Characteristics of normal and discoloured wood of Ilomba (Pycnanthus angolensis Exell) (1984)
    Springer
    Wood science and technology 18 (1984), S. 243-253 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary In the West African Ilomba wood (Pycnanthus angolensis Exell) discolourations frequently develop after felling, which lead to serious degradation with regard to utilization. Therefore, structure and chemical composition of normal and discoloured wood were investigated in order to characterize the original wood and give a detailed account of the reactions which lead to discolourations. According to the results Ilomba, in normal condition, is all sapwood, which explains its high reactivity. The species does not have the ability to develop heartwood; only false heartwood is formed, initiated by exogenous influences. Discolourations arising in the wood after felling are reddish-brown, due to the deposition of extraneous compounds in the lumina of the ray cells. Soluble sugars disappear and the permeability decreases as a result of tyloses development. From discoloured wood only 60% of extraneous compounds could be extracted as compared to the normal sapwood, thus indicating that polymerisation of extraneous compounds takes place. Discoloured wood appears even more susceptible to decay than the bright sapwood. The pH-value increases from about 5.5 to 7.5 during discolouration, and bacteria present within the reddish-brown zones are involved in that process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00353359
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  • 12
    Electronic Resource
    Electronic Resource
    The morphological variability of the bordered pit membranes in gymnosperms (1972)
    Springer
    Wood science and technology 6 (1972), S. 165-184 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary The membranes of bordered pits were investigated in 120 species of 47 genera of the gymnospermous families, using light and electron microscopic techniques. A great variability in the morphological structure of the pit membranes has been established. The differences in structure are pronounced and depend mainly on the genus involved. A classification of six morphological “structure types” is presented. They do not necessarily correspond with the chemical composition and the functional behaviour. The results on the variability of the pit membrane have shown the necessity of an extended definition for the torus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00351575
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  • 13
    Electronic Resource
    Electronic Resource
    On the closure of bordered pits in conifers (1967)
    Springer
    Wood science and technology 1 (1967), S. 1-13 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Zusammenfassung Der Aufbau von Hoftüpfeln in den Früh- und Spätholztracheiden vonAlbies alba, Picea abies, Pinus silvestris undThuja occidentalis wurde hinsichtlich des Verhaltens beim Schließen der Tüpfel, sowohl mikroskopisch als auch mit Hilfe von Permeabilitätsstudien untersucht. 1. Das Ansaugen der Tüpfelmembran erfolgt durch Adäsion zwischen der Kapillarflüssigkeit und der von ihr berührten Tüpfelschließhaut während des Flüssigkeitsaustritts. 2. Bei den Hoftüpfeln der Frühholztracheiden von Pinaceen muß die Oberflächenspannung der Kapillarflüssigkeit mindestens 26 dyn/cm betragen, um einen Tüpfelverschluß herbeiführen zu können. Die Tüpfel von Spätholztracheiden zeigten aufgrund ihres unterschiedlichen anatomischen Aufbaus ein verschiedenes Verhalten. Hier bestehen sowohl innerhalb derselben Holzart als auch zwischen den Holzarten deutliche Unterschiede. 3. FürThuja occidentalis konnte kein deutlich abgegrenzter Bereich für die Oberflächenspannung beim Tüpfelverschluß ermittelt werden. Die Tüpfel besitzen in Frühholz- wie in Spätholztracheiden eine ähnliche Membran. 4. Während bei den Pinaceen der Tüpfelverschluß in luftgetrockneten Proben einen weiteren Flüssigkeitsdurchtritt verhindert, bleiben die Tüpfel inThuja occidentalis (Cupressaceae) durchlässig. 5. InPinus silvestris besitzen die Markstrahltracheiden im allgemeinen Tüpfel mit linsenförmigen Tori, die während des Trocknens meist geöffnet bleiben, ebenso wie die entsprechenden Tüpfel in den Spätholztracheiden dieser Holzart.
    Notes: Summary The structure of bordered pits in springwood and summerwood tracheids ofAbies alba, Picea abies, Pinus silvestris andThuja occidentalis has been investigated in relation to their behaviour during pit closure microscopically as well as by penetrability studies. 1. The aspiration of the pit membrane takes place due to the adhesion forces between the capillary liquid and the connecting pit membrane existing during withdrawal of the liquid. 2. For bordered pits in springwood tracheids of Pinaceae, the surface tension of the capillary liquid must be at least 26 dynes/cm, in order to effect pit closure. Pits in latewood tracheids showed a different behaviour due to their different anatomical structure. Hereby, distinct variations exist within one and the same species and between various species. 3. ForThuja occidentalis no distinct range of surface tension for pit closure could be obtained. The pits in springwood as well as in summerwood tracheids have a similar pit membrane. 4. Whereas in Pinaceae the pit closure hinders further penetrability of air-dried specimens, inThuja occidentalis (Cupressaceae) the pits remain permeable. 5. InPinus silvestris, the ray tracheids, in general, possess pits with lens-shaped tori, which remain mostly open during seasoning, just as the corresponding pit types in the summerwood tracheids of the same species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00592252
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  • 14
    Electronic Resource
    Electronic Resource
    Book reviews (1985)
    Springer
    Wood science and technology 19 (1985), S. 178-178 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00353078
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  • 15
    Electronic Resource
    Electronic Resource
    The significance of anomalous extractives in heart-shakes in Dacrydium species (1976)
    Springer
    Wood science and technology 10 (1976), S. 79-95 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Morphological and chemical examinations of the extractives of the tissues and shake contents of eight Dacrydium and one Podocarpus species have been made. The whitish deposits in heart-shakes are without exception mainly podocarpic acid (PCA). This compound occurs also in the tissue of samples but only when shakes are found nearby. Accordingly PCA is regarded as an anomalous extractive, synthesized in response to those conditions resulting in shake formation. In samples with shakes PCA is present in very small amounts at the sapwood-heartwood boundary and in one sample there were traces even in the innermost sapwood. It was notable that shakes containing deposits can arise in those Dacrydium species with coloured heartwood and with a known tendency for wetwood formation. On the other hand Dacrydium franklinii does not develop coloured heartwood or wetwood or shakes, and the lack of these features may have taxonomic significance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00416784
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  • 16
    Electronic Resource
    Electronic Resource
    Woodbiological investigations on panels of rembrandt paintings (1981)
    Springer
    Wood science and technology 15 (1981), S. 251-263 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary Paintings on 150 wooden panels accepted and not accepted as authentic Rembrandts were investigated using wood-anatomical and dendrochronological techniques. Paintings on 131 panels came from oaks in the coastal area of the Netherlands and 1 panel came from an oak in the interior. The wood of the remaining 18 panels was from beech, poplar and walnut, presumably from the Netherlands, and from cedrela, mahogany and jequitiba imported from Central and South America. In several cases wood of different panels was from the same trunk. By determining the felling date of a tree, a “terminus post quem” could be set for the production of the panel and the completion of the painting, respectively. The art-historical dating of most paintings could be dendrochronologically confirmed. In some cases the attribution was corrected by a few years. In one case an older panel was re-used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350943
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  • 17
    Electronic Resource
    Electronic Resource
    Book reviews (1983)
    Springer
    Wood science and technology 17 (1983), S. 194-194 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00372317
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  • 18
    Electronic Resource
    Electronic Resource
    Influence of oxygen and substrate supply on the metabolism of Candida maltosa during cultivation on n-alkanes (1989)
    Springer
    Applied microbiology and biotechnology 32 (1989), S. 101-107 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The influence of different states of oxygen and alkane substrate supply on the metabolism of Candida maltosa during cultivation on n-alkanes has been investigated. At sufficient oxygen and substrate supply a nearly equimolar ratio between the formation of biomass and alkane oxidation was observed. About 45% of the carbon source utilized was incorporated into the biomass. Strong oxygen limitation decreased protein formation and carbon incorporation into the biomass with a simultaneous increase in CO2 formation, whereas periodic changes of oxygen supply only caused a decrease in carbon incorporation into the biomass and an increase in CO2 formation. During cultivation in the presence of an inert hydrocarbon (pristane) it was found that carbon limitation and oxygen saturation diminished the formation of total and nitrogen-containing biomass, whereas carbon and oxygen limitation reduced the formation of total biomass.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00164830
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  • 19
    Electronic Resource
    Electronic Resource
    Element content in tissues of spruce seedlings from hydroponic cultures simulating acidification and deacidification (1988)
    Springer
    Plant and soil 106 (1988), S. 231-238 
    Details
    ISSN: 1573-5036
    Keywords: fine roots ; hydroponic cultures ; metal ion stress ; nutrient deficiency ; soil acidification ; spruce
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In order to determine the primary causes of coniferous fine root damage and disfunction in acidic soils, hydroponic cultures of young spruce in pH neutral, acidic, and metal ion-amended media were established. After five months, physiological stress in the roots was removed by raising the pH in the acid and metal ion-amended cultures to physiological neutrality. The cellular element analytical techniques of x-ray microprobe (EDXA) and laser-micromass-spectroscopy (LAMMA) were applied to samples of various tissues of the cultured spruce. Nutrient uptake by the fine roots was blocked by the following ions in order of decreasing severity: Al3+〉H+〉Fe3+〉Mn2+. Magnesium uptake by the fine root apoplast was greatly inhibited by these blockers as was calcium. Al3+ and Fe3+ act predominantly in the root cortex, while Mn2+ is mobile throughout the whole plant. Besides the roots, nutrient deficiencies are also severe in the shoot bark and needles. Phloem processes might therefore be affected. The ion exchange functions of the fine roots are almost reversed by raising the pH of the solutions; the nutrient cations may then again be taken up by the apoplast and the crown status improved. The consequences of these findings are discussed with regard to soil processes and fertilization (liming) treatments under field conditions
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02371218
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  • 20
    Electronic Resource
    Electronic Resource
    Monitoring uptake and contents of Mg, Ca and K in Norway spruce as influenced by pH and Al, using microprobe analysis and stable isotope labelling (1995)
    Springer
    Plant and soil 168-169 (1995), S. 135-150 
    Details
    ISSN: 1573-5036
    Keywords: Al effect ; microprobe analysis ; nutrient uptake ; pH effect ; Picea abies ; stable isotope labelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In a model system using intact spruce trees (Picea abies [L.] Karst.) we followed the path of magnesium, calcium and potassium during uptake into the root and during long-range transport into the shoot, by multiple stable isotope labelling. The roots of two- and three-year-old spruce trees originating from soil culture were removed from the soil and, in part or in toto, exposed to labelling solutions containing the stable isotopes 25Mg or 26Mg, 41K and 42Ca or 44Ca. Optical-emission-spectroscopy (ICP-OES) of plant fractions and labelling solutions was combined with the quantitative analysis of stable isotope ratios in sections of shock frozen, cryosubstituted material using the laser-microprobe-mass-analyser (LAMMA). This combination allowed us to distinguish, both in bulk samples and on the cellular level between (i) the fraction of elements originally present in the plant before the start of the labelling, (ii) the material taken up from the labelling solution into the plant and (iii) any material released by the plant into the labelling solution. In single-root labelling experiments, roots of three-year-old spruce trees, grown in nursery soil, were exposed to various pH conditions. The exchange of Mg and Ca with the labelling solution was nearly 100% in the cell walls of the mycorrhized finest roots. This exchange was only slightly affected by a step down to pH 3.5. The absolute Mg and Ca content in the cell walls was moderately reduced by incubation at pH 3.5 and strongly reduced in the presence of Al at this pH. After a pH 3.5 and 2 mM Al treatment we found Al in the xylem cell walls and the cortex cell lumina at elevated concentrations. To analyse the combined effect of high Al and high proton concentrations on the long-range transport, we used a “split-root system”. The root mass of an intact two-year-old spruce tree, grown in mineral soil, was divided into even parts and both halves incubated in solutions with two sets of different stable isotopes of Mg and Ca (side A: no Al, 25Mg and 42Ca; side B: +Al, 26Mg and 44Ca) and 41K on both sides. We observed a large uptake of Mg, Ca and K into the plant and a pronounced release. The net uptake of all three elements was lower from the Al-doted solution. In cross-sections of the apical shoot we found after seven-day labelling period about 60–70% of the Mg and Ca and 30% of the K content in the xylem cell walls originating from both labelling solutions. The clear majority of the Mg and Ca label originated from the Al-doted side.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00029322
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