Cell Wall

Cell-wall is the non-living component of cell. It is secreted and maintained by living portion of cell called protoplasm. The chief structure component of plant cell-wall is cellulose, a polysaccharide. In addition to cellulose, pectin and a few other compounds, may also be found in cell wall.
A plant cell-wall can differentiated into three regions,

1. Middle Lamella
2. Primary Wall
3. Secondary Wall

Middle Lamella:
The first formed cell plate as a cementing layer between two daughter cells and is called middle lamella. It is a common layer between two cells and the two cells are separated when middle lamella is dissolved. It is composed of calcium and magnesium spectates.

Primary Wall:
Bordering middle lamella, primary wall is the first product of cell, synthesized by protoplast. In young enlarging cells primary wall remains thin and elastic becoming thick and regid with the approach of cell maturity. Primary wall contains hemicellulose up to 50 percent, cellulose up to 25 percent and smaller amount of pectic substances. Hemicellulose forms matrix of the wall in which cellulose micro fibrils are embedded.

Secondary Wall:
Secondary wall is formed be deposition of cellulose at the inside of primary wall. It mainly consists of cellulose or varying mixtures of cellulose. Secondary wall may be modified through the deposition of Lignin and other substances

In the cell wall cellulose deposits in the form of fibres. The cellulose fibres of each successive layer lie at different angels, increasing the strenght of the cell-wall. A t places area known as plasmodesmata ( Singular-plasmodesma ) through which cellular contents of neighboring cells remain in communication with each other.