Lateral roots serve as the plant’s secure anchor to the soil and they extend horizontally from the primary root. Such branching of the root can help in the uptake of water and in facilitating the extraction of nutrients that is needed for the plant’s growth and development.

Several factors are involved in the growth and formation of lateral roots. Auxin is a plant hormone that tightly controls the regulation of root formation.  This kind of control is useful as the increased levels of auxin helps promote the development of lateral roots, and often happens during the formation of the young leaf primordia. This enables a balance between nitrogen and carbon metabolism to be established.

Lateral Root Development

Lateral roots normally develop when the plant is from seven to nine days old.

There are four distinguished morphological stages of lateral roots, which are:

  1. Stage I: This is the stage wherein the pericycle’s asymmetric division of two cells, referred as pericycle founder cells, is already identifiable. They are next to the protoxylem poles, wherein the lateral roots entirely came from. Cells will then undergo division that causes radial expansion.

  2. Stage II: The tiny cells in the center will divide periclinally, in parallel to the plant body surface and in a sequence of transverse, asymmetric divisions, making the young primordium visible.

  3. Stage III: The outer layer of cells will divide in order for the primordium to have three layers. Then they will under a similar division so that the fourth layer will be made visible.

  4. Stage IV: Further division and expansion of the four layers will result to the young lateral root’s emergence from the overlying tissues of the primary root, known as the parent tissue, at this stage.

©2005-2015 Plant Biology Advice - Dean Ravenscroft