Structural Function - Essential Elements

The elements nitrogen, phosphorus and sulphur absorbed from the soil are essential components of amino acids and nucleotides. The other two elements that are constituents of important compounds are Mg²⁺ and ca²⁺. While Mg²⁺ is part of chlorophyll molecule and ca²⁺ is an integral part of the middle lamella and is thought to be essential for maintaining structural characteristic of cell walls. It also maintains the permeability of plasma membrane.

In its absence cells begin to leak out. In recent years a new regulatory role that ca²⁺ plays in the cell is beginning to be appreciated.  It plays the role of a second messenger.