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Aufnahme und Verteilung von 15 N‐markiertem Harnstoff bei Phaseolus vulgaris L
Author(s) -
Hentschel G.
Publication year - 1976
Publication title -
zeitschrift für pflanzenernährung und bodenkunde
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 0044-3263
DOI - 10.1002/jpln.19761390211
Subject(s) - phaseolus , urea , ammonium , chemistry , nitrogen , ammonium chloride , nuclear chemistry , transpiration , absorption (acoustics) , biochemistry , horticulture , biology , organic chemistry , photosynthesis , physics , acoustics
The Uptake and Distribution of 15 N‐Labelled Urea by Phaseolus vulgaris L The uptake of two‐fold 15 N‐labelled urea via the root system of 21 days old plants of Phaseolus vulgaris in comparison with 15 N‐marked ammonium chloride has been investigated. The concentration of urea or ammonium resp. was 3 mmol/l. The plants were allowed to take up the labelled nitrogen for an 8 hours period. The determination of the 15 N‐frequency was carried out by emission spectrometry. The results demonstrate that urea is taken up as a whole undestructed molecule. Also there is evidence for a 7‐fold enrichment of urea in the exsudation sap in comparison with the urea concentration in the nutrition solution. Inhibition of the metabolic activity of the roots (2,4‐DNP, KCN, AsO 4 , N 2 ) reduces both the urea and the ammonium absorption to a considerable rate. Variations of the transpiration, of the Ca/K ratios or p H in the nutrition solution have none or only a very small influence on the uptake of urea. There may be the possibility for the existence of a common mechanism for the absorption of both urea and ammonium.