Upon seed germination, the embryo root, called the radicle, grows and develops into the first root. The radicle may thicken into a taproot with many branching roots, or it may develop into many adventitious roots. The direct opposite of a taproot system is a fibrous root system. This develops out of the many adventitious roots. In diameter, the roots in a fibrous system are very fine. There are many mature plants that have a combination system, which means there is the main taproot with many branching fibrous roots attached. Root hairs, or extensions of the epidermis as explained in the Plant Tissue tutorial, significantly increase the contact surface area of the root system. This allows for more exchange with the surrounding soil.

Read more