Origin and Physiology of Adventitious Roots

Physiology of lateral primordia formation

Physiology of lateral primordium formation in the Adventitious Root System has a clear explanation: the LR is formed from the periclinal region of the stele, which in turn generates two long strip cells that form the primary primordia. The periclinal region also contributes to the formation of the root cap, and continued cell division within the root cap forms the mature region.

In plants, the adventitious root system plays an important role in gas transport, nutrient uptake, and flood tolerance. Its morphological changes and signaling pathways help the plant survive flooding. Physiological changes are mediated by the expression of ethylene and auxin.

Physiology of polar auxin transport

Auxin is a key component in lateral root initiation. It is transported from the apical to the basal endodermal cells by a functionally redundant network of PIN efflux carriers. During the initiation phase, PIN1 is localized at anticlinal membranes. During the subsequent pericycle cell division phase, PIN1 is redistributed to the outer lateral plasma membranes of inner cells.

In addition, polar auxin transport regulates the angle at which ARs grow. The architecture of the AR system is largely determined by this process.