Hint: This element is a key chlorophyll component that supports the role to absorb sunlight during photosynthesis. It also acts as a carrier of phosphorus in plants and is important for the metabolism of phosphates.
> Option A is incorrect. Potassium is associated with the movement of plant tissue in water, nutrients, and carbohydrates. It triggers the formation of enzymes within the plant that affect protein, starch, and adenosine triphosphate (ATP) production. The rate of photosynthesis can be regulated by ATP production.
> Option B is incorrect. Iron is an important micronutrient for nearly all living organisms because it plays a vital role in metabolic processes including synthesis of DNA, respiration, and photosynthesis. Iron is involved in chlorophyll synthesis and is important for preserving the structure and function of chloroplasts.
> Option C is incorrect. Manganese is an important mineral nutrient in plants and plays a key role in several physiological processes, particularly photosynthesis. It has relatively low phloem mobility in plants and hence typical Mn-deficiency leaf symptoms grow first in younger leaves. Manganese stimulates the enzyme involved in photosynthesis and nitrogen metabolism, specifically for the release of oxygen by water photolysis.
> Option D is correct. Chlorophyll contains a magnesium ion encased in a large chlorine ring framework. The chlorine ring is a pyrrole derivative heterocyclic compound. Chlorin surrounds four nitrogen atoms and binds the magnesium atom. The magnesium core especially describes the structure as a molecule of chlorophyll.
Hence, The correct answer is option (D).
Note: Magnesium helps plants take essential nutrients, such as nitrogen and phosphorus, better. It greatly enhances the ability of a plant to produce flowers and fruit, and its deficiency can minimize photosynthesis, stall growth, and prevent different plants in the lawn and garden from achieving their full potential.