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  • Aufgangsverspätung  (1)
  • Organic Chemistry  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Potato research 36 (1993), S. 143-151 
    ISSN: 1871-4528
    Keywords: Solanum tuberosum L. ; Warmlagerung ; Keimintensität ; Schwund ; Aufgangsverspätung ; Bestandesdichte ; Ertrag
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Summary Seed tubers were stored at above optimal temperatures. Mean temperatures varied during test years from 16 to 29.5°C (in 1988–1990 tubers desprouted before planting; in 1991 chitted tubers as in control; Table 1). This procedure of physiological ageing of seed tubers resulted in reduced plant density and lower yield compared to the chitted control in every year of the test period (average of 25 cultivars). The emergence was significantly delayed as compared to the control in all years (Table 2). Assessed for yield, the cultivars Désirée, Sanetta, Astilla and Andra showed a significantly higher degree of tolerance to warm storages (〉80%, when compared to the control) than the cultivars Arkula, Dorisa, Karlena and Koretta (〈25%; Table 3). Between these two extremes there was a large number of intermediate levels of tolerance, a result of fluctuating reactions of various cultivars to changing conditions in the years of the test period (Fig. 1). No correlation could be found between the cultivars' reactions and their maturity group or their sprouting behaviour. There was, however, for each cultivar a significant negative correlation between loss in weight through transpiration and respiration and plant density and yield (r=−0.55 and −0.54; Table 4). Plant density and yield were closely correlated (Table 4). The regressions between loss of plants and reductions in yields show that after seed tuber storage at higher temperatures a reduced yield must be expected even when plant density is not reduced (loss of plant 0%; Fig. 2). With complete stands, the use of physiologically aged seed tubers that were desprouted before planting (1988–1990) resulted in a reduction of yield of 17–20%; when old seeds were chitted as in control a loss in yield of 15% was calculated.
    Notes: Zusammenfassung Die physiologische Alterung der Pflanzknollen durch Lagerung bei überoptimalen Temperaturen (jahresunterschiedlich 16–29,5°C, 1988–90 vor dem Pflanzen abgekeimt, 1991 vorgekeimt wie Kontrolle) führte im Vergleich zur vorgekeimten Kontrolle im Mittel von 25 Sorten in allen Versuchsjahren zu einer Verminderung der Bestandesdichte und des Ertrages. Eine Gruppe von Sorten erwies sich in allen Jahren als relativ tolerant gegen die Alterung, eine andere als signifikant empfindlicher, dazwischen lag ein breites Mittelfeld mit zum Teil erheblichen Schwankungen in den Jahren. Die Reaktion der Sorten zeigte keine Beziehung zu ihrer Reifegruppe und ihrer Keimintensität, dagegen war die sortentypische Ertragsdepression nicht sehr eng, aber signifikant mit dem Schwund während der Lagerung korreliert.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 319 (1977), S. 647-654 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Influence of the Polymer Matrix on the Thermal Back Reaction of Photochromic 2,4-Dinitrobenzyl PyridinesIn solid solution with polymers (polymethylmethacrylate, polyethyl acrylate and polystyrene) below Tg the thermal back reaction of the coloured forms of photochromic 2-(2′,4′-dinitrobenzyl)pyridines 1-3 can be described by second-order kinetics whereas above Tg (in polyethyl acrylate) the reaction is first order. The life time of coloured form depends on polymer structure and is longest in polar polymers of high molar mass. These results as well as the Δ≠ and ΔH≠ values are discussed applying the concept of reaction cavity to the solid solutions.
    Notes: In fester Lösung in Polymeren (Polymethylmethacrylat, Polyäthylacrylat und Polystyrol) wird die Kinetik der thermischen Rückreaktion der Farbformen der photochromen 2-(2′,4′-Dinitrobenzyl)-pyridine 1-3 unterhalb Tg durch ein Zeitgesetz 2. Ordnung, oberhalb Tg (in Polyäthylacrylat) durch ein Zeitgesetz 1. Ordnung beschrieben. Die Lebensdauer der Farbform ist von der Konstitution des Polymeren abhängig und ist am größten in polaren Polymeren hoher Molmasse. Diese Ergebnisse und die ΔS≠ - und ΔH≠ - Werte werden unter Anwendung des Begriffes der Reaktionshöhlung auf die festen Lösungen diskutiert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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