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Abstract

Applications of potassium fertilisers may reduce
the amount of magnesium in plants, at times to a degree
which produces symptoms of magnesium deficiency. As well as
its effects on the availability of soil magnesium, potassium
affects the amount of magnesium in the plant in two ways:
by competition at the site of uptake, thus resulting in a
lower total plant magnesium, or by reducing transport of
magnesium between plant organs. There is disagreement on
the relative importance of these factors. The kinetics of short term uptake of potassium and
magnesium by detached barley roots were studied by methods
based on the Michaelis-Menten theory of enzyme-substrate
relationships. These experiments showed competitive
inhibition of magnesium by potassium but not of potassium
by magnesium. This may be explained by proposing that
there are many sites of potassium uptake and that some of
them are free of magnesium competition. Competitive
inhibition of a divalent ion by a monovalent ion has not
been observed previously, earlier reports being confined
to competition between ions of like valency. An apparent
stimulation of potassium uptake by magnesium was found to
be due to the influence of a common anion (chloride).

Item Type:	Thesis - PhD
Authors/Creators:	Lamp, CA
Keywords:	Plants, Potassium, Magnesium
Copyright Holders:	The Author
Copyright Information:	Copyright 1968 the Author - The University is continuing to endeavour to trace the copyright owner(s) and in the meantime this item has been reproduced here in good faith. We would be pleased to hear from the copyright owner(s).
Additional Information:	Thesis (Ph.D.) - University of Tasmania, 1968. Includes bibliography
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