ISSN:
1573-5036
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract 1. Rice was grown for 5 months in a sand solution culture at two different (1) K levels. The higher K supply resulted in a reduced uptake of Na +, Mg ++, and Ca++ by shoots. The uptake of NH4+-N of the shoots, however, was increased by the higher K supply. (2) In short term experiments, ill which the NH4+-N of the uptake solution was labelled by N 15, increasing K concentrations in the uptake solution did not depress the NH4 + uptake of young rice plants. Higher K concentrations in the uptake solution favoured the translocation of labelled N from the roots to the shoots. In some cases the higher K levels resulted also in an enhanced transfer rate of labelled N from the soluble to the insoluble N fraction. (3) Increasing levels of Mg++ in the uptake solution did not affect the uptake of labelled NH4-N. (4) I t is concluded that K + and NH4 + do not compete for common binding sites of the uptake mechanism in rice roots. This lacking competition suggests the speculation that NH4+-N is absorbed mainly in form of NH8 by plant cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00011374
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