Effect of pH on the Absorption of Boron by Excised Barley Roots
- J. J. Oertli and
- E. Grgurevic2
In order to obtain information on the mechanism of B uptake and on the relative importance of the two forms H3BO3 and H2BO3− for net B absorption, the uptake of B by excised barley (Hordeum vulgure var. Briggs) was investigated using solutions having pH values from 6 to 10 and B concentrations from 1 to 10 ppm. The B uptake and final B contents after 1 hour absorption periods increased nearly linearly with increasing B supply. The relative B uptake (uptake at pH 6 = 100%) at all supply levels decreased with increasing pH similar to the decrease of the fraction of undissociated H3BO3. At pH 6 final B contents in roots and treatment solutions were similar. From this it is concluded that B in root tissues and external solution tends to approach a diffusion equilibrium which is governed by the undissociated acid. Boron thus differs fundamentally from most other nutrients which are present in an ionized form and are transported actively.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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