Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    An analytical microscopical study on the role of the exodermis in apoplastic Rb+(K+) transport in barley roots (1998)
    Springer
    Plant and soil 207 (1998), S. 209-218 
    Details
    ISSN: 1573-5036
    Keywords: Cryosectioning ; endodermis ; ion localisation ; ion transport ; rhizodermis ; X-ray microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The paper investigates how the apoplastic route of ion transfer is affected by the outermost cortex cell layers of a primary root. Staining of hand-made cross sections with aniline blue in combination with berberine sulfate demonstrated the presence of casparian bands in the endo- and exodermis, potentially being responsible for hindering apoplastic ion movement. The use of the apoplastic dye Evan's Blue allowed viewing under a light microscope of potential sites of uncontrolled solute entry into the apoplast of the root cortex which mainly consisted of injured rhizodermis and/or exodermis cells. The distribution of the dye after staining was highly comparable to EDX analyses on freeze-dried cryosectioned roots. Here, we used Rb+ as a tracer for K+ in a short-time application on selected regions of intact roots from intact plants. After subsequent quench-freezing with liquid propane the distribution of K+ and Rb+ in cell walls was detected on freeze-dried cryosections by their specific X-rays resulting from the incident electrons in a SEM. All such attempts led to a single conclusion, namely, that the walls of the two outermost living cell sheaths of the cortex largely restrict passive solute movements into the apoplast. The ring of turgescent living rhizodermis cells in the root tip region forms the first barrier. With increasing distance to the root tip, in the course of their maturation resp. degradation, this particular function of the rhizodermis cells is replaced by the hypodermis resp. exodermis. Furthermore, the restriction of apoplastic ion flow by the outermost cortex cell layers is rather effective but not complete. Thus, the solute transfer into the stele is mainly restricted by the casparian bands of the endodermis. The overall conclusion is that the resistances of the rhizodermis and exodermis are additive to the endodermis in their role of regulating the apoplastic solute movement across roots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004437516331
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Dünndarmresorption bei Krebskranken — Grundlagen für die enterale Ernährungstherapie in der Onkologie (1984)
    Springer
    European journal of nutrition 23 (1984), S. 157-170 
    Details
    ISSN: 1436-6215
    Keywords: Dünndarmresorption ; Tumorstadium ; histologischer Typ ; Organlokalisation ; Ernährungstherapie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Summary A deteriorating nutritional condition combined with the loss of body mass is one of the most noticeable symptoms of cancer. In order to answer the question to what extent absorption disorders in the small intestine are responsible for the malnutrition which develops, we studied 54 oncologic patients using modified D-xylose absorption tests. After the oral and intravenous administration of 10 g D-xylose at different times, the degree of absorption dependent on time was determined on the basis of a biophysical model. When accompanied by general nonspecific tumor symptoms, the frequency of absorption restrictions was increased. An established relation was found between the extent of small intestinal absorption, on the one hand, and the degree of spreading (staging) and the degree of histological differentiation of the carcinoma, on the other hand. Enteral absorption disorders represent a partial cause for the development of malnutrition in cancer patients and must be viewed as a result of a metabolic situation which is distinctly catabolic.
    Notes: Zusammenfassung Die Verschlechterung des Ernährungszustandes und die Abnahme an Körpermasse ist eines der auffälligsten Symptome des Krebsleidens. Zur Beantwortung der Frage, inwieweit Störungen der Dünndarmresorption für die sich entwickelnde Malnutrition verantwortlich zu machen sind, untersuchten wir 54 onkologische Patienten mit Hilfe des modifizierten D-Xylose-Resorptionstests. Nach zeitlich getrennter oraler und intravenöser Applikation von 10 g D-Xylose wurde auf der Grundlage einer biophysikalischen Modellierung das Ausmaß der Resorption in Abhängigkeit von der Zeit ermittelt. Mit dem Auftreten allgemeiner unspezifischer Tumorsymptome erhöht sich die Häufigkeit von Resorptionseinschränkungen. Es konnte eine gesicherte Beziehung zwischen Ausbreitungsgrad (Staging), histologischem Differenzierungsgrad des Karzinoms einerseits und dem Ausmaß der Dünndarmresorption andererseits nachgewiesen werden. Enterale Resorptionsstörungen stellen eine Teilursache bei der Entwicklung einer Mangelernährung bei Krebskranken dar und sind selbst als Folge der katabol akzentuierten Stoffwechsellage anzusehen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02021470
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...