Brace roots

In botany, brace roots (roots developing from aerial stem nodes) are a type of adventitious root that develop from aboveground stem nodes in many monocots. Anchorage, water and nutrient acquisition are the most important functions of roots. Thus, plants develop roots that maximize these functions for productivity and survival. In cereals such as maize, brace roots are one of the roots that contribute to these important functions. Brace roots develop constitutively in whorls from stem nodes, with the lowest whorl being the first to develop, enter the soil, branch out, and contribute the most to anchorage. Subsequent whorls may enter the soil and contribute to anchorage and resource acquisition, but they may also remain aerial. While these aerial roots do not contribute as much to anchorage, they could contribute in other ways such as forming an association with nitrogen-fixing bacteria.

Brace roots may remain aerial or penetrate the soil as they perform root functions such as anchorage and resource acquisition. Although brace root development in soil or aerial environments influences function, a lot is still unknown about how their anatomy, architecture and development contributes to their function. The physiology of brace roots is directly linked to their anatomy, architecture, and development. The dynamic interplay of internal regulators such as transcription factors, miRNAs, and phytohormones, lay the foundation for brace root development. Once brace roots emerge from stem nodes, the influence of external factors such as the availability of water, nutrients, light and humidity become prominent. Therefore, a combination of internal and external factors determine the overall organization, shape, and size of individual roots (root system architecture) and, as a result, root function.