Root Cap

The root cap comprises several layers of parenchyma cells that lie upon each other, giving a dome or thimble shape. The cells that border the root cap are referred to as peripheral cells. Root also contains a specialized group of cells, called statocytes, involved in gravity perception. These statocytes direct the downwards growth of plant roots.

Formation

A new root cap cell layer is formed via periclinal division of proximal stem cells present in apical meristematic region. Periclinal division involves the division of cells parallel to the plane of division. On the other hand, the oldest cell layer at the outermost position, the peripheral cell, disintegrates. By this process, the older cell layer gets detached at a constant interval while they are still alive.

Due to this continuous autonomous process, the root cap constantly gets renewed. So, it is always composed of viable cells.

1. It protects the growing tip in plants by covering the sensitive tissue in the root meristem.
2. It secretes mucilage to avoid the friction of roots while passing through the soil. Thus, it lubricates the movement of the root through the soil.
3. The root cap contains statocytes, which help in geoperception or gravitropism. Its gravity sensing property enables the root to grow in response to gravity, i.e., downwards.
4. It is also involved in communication with the soil microbiota. The root cap receives and transmits environmental signals to the growing root.