Which one of the following elements is present in green pigment of leaf?

Chlorophyll is the essential green pigment found in the chloroplasts of plant leaves, responsible for capturing light energy during photosynthesis [1]. Chemically, the chlorophyll molecule is characterized by a porphyrin ring structure, which is remarkably similar to the heme group in hemoglobin [1]. However, while hemoglobin contains iron as its central atom, chlorophyll contains magnesium as its central core [1]. Magnesium is an essential macronutrient for plants, serving as the central atom of every chlorophyll molecule. Without sufficient magnesium, plants cannot synthesize enough chlorophyll, leading to interveinal chlorosis where leaves turn yellow while veins remain green. While other elements like nitrogen are also integral parts of the chlorophyll structure [2], magnesium is the specific metallic element at the center of the pigment's functional ring [1].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 5: Life Processes > QUESTIONS > p. 82
2. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 25: Agriculture > Nitrogen (N) > p. 363