Question

How do plants influence the uptake of cations such as magnesium involving cation exchange?

Answer 1

The soil cations are essential for plant growth. It is enabled by cation exchange.

Dihydrogen monoxide or simply water in soil reacts with carbon dioxide and produce carbonic acid. The carbonic acid releases protons. This cation exchange is compelled by the release of carbon dioxide by root cells.

Answer 2

Plants they do influence the uptake of cations such as magnesium which involves cation exchange,

 by the process of releasing carbon dioxide.

The cation exchange is being driven by the release of carbon dioxide by root cells reason being carbon monoxide reacts with water which is in the soil to produce carbonic acid whereby its work is to release protons.
 Magnesium is very important in plant nutrient. The main role of magnesium in plants is that it helps in the photosynthesis process which builds chlorophyll which now makes the leaves appear green.