title: Determination of Root Exudates in a Steril Continuous Flow Culture. II. Short-Term and Long-Term Variations of Exudation Intensity.
abstract: The exudate production of alfalfa under the conditions of the sterile flow culture was quantitatively measured. In the first 40 days 3.10(-3) mumoles amino-N, 2.5 muequivalents of organic acids and approximately 10(-4) mumoles of reducing sugars were liberated per plant and per day into the percolating nutrient solution. The amino acid concentration in the outflow varies according to a daily periodicity. The exudation of a colored substance also shows daily periodical variations. This pattern is different from the pattern of the amino acid exudation, however, and directly coupled to shoot illumination. Short-term 2,4-dinitrophenol additions to the nutrient lower the liberation of amino acids into the percolating solution.
authors.affiliation: Institut fuer Bodenkunde der Georg August Universitaet, Goettingen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Richter
authors.forename: W
authors.initials: W
authors.lastname: Wilms
authors.forename: F
authors.initials: F
authors.lastname: Scheffer