Why do plants need magnesium ions for healthy growth?

+87 votes
asked Aug 21, 2015 in Science by EPILayne8636 (240 points)
I understand that human bodies need magnesium and other trace elements to function properly. But I always thought of plants as a rather primitive form of life and never realized that they also need magnesium ions for healthy growth. But what is the use of magnesium in plants?

1 Answer

+29 votes
answered Sep 7, 2015 by AlannahGwend (350 points)
Plants need magnesium ions, because magnesium is a key element in chlorophyll. You said you understood that magnesium is essential to human health but didn’t realize its role in plants, which is just as important. However, if we trace the history, the first time magnesium was discovered in living tissue was in a study of chlorophyll. That is to say, we came to understand the importance of magnesium in the growth of plants earlier than we even knew that there is magnesium in human bodies.

Because magnesium is crucial for making chlorophyll, to understand why do plants need magnesium ions for healthy growth is to understand the importance of chlorophyll. Plants are defined by chlorophyll: the primary role of plants in the cycle of life on Earth is to exploit the sunlight energy for transforming carbon dioxide and water to glucose and oxygen. This process is better known as photosynthesis, and it cannot be done without chlorophyll.

The contribution of chlorophyll in photosynthesis is two-fold: first, the majority of chlorophyll in a plant absorbs the energy from light and transfers it to the other portion of chlorophyll in the so-called reaction center; second, the reaction center chlorophyll uses the received energy to oxidize water into oxygen and hydrogen ions. This is, incidentally, where practically all the oxygen in the atmosphere comes from. And magnesium is important in chlorophyll, because it forms the central atom of it and has a pivotal role to play in both the transferring and oxidization processes.

If a plant is deficient in magnesium, it would be quite easy to discern. This is because chlorophyll is a kind of pigment that renders plant leaves green. If a plant doesn’t have sufficient magnesium, the chlorophyll in it will tend to degrade gradually, and the leaves of the plant will turn yellow. Two of the most common causes of magnesium deficiency in plants include excess potassium and aluminum toxicity.
commented Sep 11, 2015 by DaniellePoin (150 points)
This is the most clear explanation I have ever read on this topic. I'm so glad that I found this website!
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