Scribd
Upload
573 views2 pages

Ion Antagonism

Ion antagonism occurs when one ion influences the effect of another ion on plants. Ions can either increase or decrease each other's effects. This antagonistic effect happens at the uptake level, where heavy absorption of one nutrient can cause a deficiency of another. For example, heavy application of magnesium can induce potassium deficiency. The antagonistic effect is sometimes due to competition between ions for the same carrier site during uptake. Similarly, ion pairs also show competitive behavior in their uptake. Calcium chloride can diminish the increasing permeability effect of sodium chloride under certain conditions. Antagonism is also seen between ion toxicities, such as calcium reducing the toxicity of copper ions and allowing for greater root elongation.

Uploaded by

Gautami
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
573 views2 pages

Ion Antagonism

Ion antagonism occurs when one ion influences the effect of another ion on plants. Ions can either increase or decrease each other's effects. This antagonistic effect happens at the uptake level, where heavy absorption of one nutrient can cause a deficiency of another. For example, heavy application of magnesium can induce potassium deficiency. The antagonistic effect is sometimes due to competition between ions for the same carrier site during uptake. Similarly, ion pairs also show competitive behavior in their uptake. Calcium chloride can diminish the increasing permeability effect of sodium chloride under certain conditions. Antagonism is also seen between ion toxicities, such as calcium reducing the toxicity of copper ions and allowing for greater root elongation.

Uploaded by

Gautami
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
You are on page 1/ 2

ION ANTAGONISM

Some ions influence the effect of other ions on plants. They


may either increase the effect (potentiate) or retard it. The
inhibitory effect of one ion on the function of the other is called
ion antagonism. This antagonistic effect is affected at the
uptake level of ion. For most of the alkali cations ( like
magnesium, calcium, potassium etc.) the uptake of one is
generally reduced when the other one is available in plenty.
Such antagonistic effect may be so severe that heavy
absorption of one nutrient may cause a deficiency of the other.
For example, potassium deficiency may be induced by heavy
application of magnesium.

For some ions it has been observed that the antagonistic effect
is because of competition in their uptake. Potassium , rubidium
and caesium have been found to compete with one another
for the same carrier site, in barley roots. Similarly Cl- - Br-, Ca 2- -
Sr2-, and SO42- - SeO42- ion pairs also show competitive behavior
in their uptake. Sometimes even unrelated ions which are not
transported by similar active site also interfere with the uptake
of each other.

Sodium chloride results in an increase in permeability of


cytoplasmic membranes to various solutes under certain
conditions. If calcium chloride is introduced into the medium,
however this increasing effect is diminished.

Similar antagonistic effects are evident in the toxicity


phenomenon. For example in one experiment it was found that
the roots of lupines would elongate only 3.5 mm per day in a
solution of 0.000015 M CuCl2 but if sufficient CaCl2 was added
the roots elongated at 10.5 mm per day. The antagonism
between the Cu++ and Ca++ ions was sufficient to reduce greatly
the toxicity of Cu++ ions.

____________________________________________________

You might also like