Editing Root (section)

===Terms and components===
The main terms used to classify the architecture of a root system are:<ref name=Fitter>{{cite book| vauthors = Fitter AH |chapter=The ecological significance of root system architecture: an economic approach|title=Plant Root Growth: An Ecological Perspective | veditors = Atkinson D |year=1991 |pages=229–243 |publisher=Blackwell |isbn=978-0-632-02757-6 }}</ref>

{| class="wikitable"
|-Root || Root can hold the plant firmly to the ground and it absorb water and neutrients
| Branch magnitude || Number of links (exterior or interior)
|-
| Topology || Pattern of branching ([[Herringbone pattern|Herringbone]], [[Dichotomous]], [[Radial symmetry|Radial]])
|-
| Link length || Distance between branches
|-
| Root angle || Radial angle of a lateral root's base around the parent root's circumference, the angle of a lateral root from its parent root, and the angle an entire system spreads.
|-
| Link radius || Diameter of root
|}

All components of the root architecture are regulated through a complex interaction between genetic responses and responses due to environmental stimuli. These developmental stimuli are categorised as intrinsic, the genetic and nutritional influences, or extrinsic, the environmental influences and are interpreted by [[signal transduction pathways]].<ref name=Malamy>{{cite journal | vauthors = Malamy JE, Ryan KS | title = Environmental regulation of lateral root initiation in Arabidopsis | journal = Plant Physiology | volume = 127 | issue = 3 | pages = 899–909 | date = November 2001 | pmid = 11706172 | pmc = 129261 | doi = 10.1104/pp.010406 }}</ref>

Extrinsic factors affecting root architecture include gravity, light exposure, water and oxygen, as well as the availability or lack of nitrogen, phosphorus, sulphur, aluminium and sodium chloride. The main hormones (intrinsic stimuli) and respective pathways responsible for root architecture development include:
{| class="wikitable"
|-
| [[Auxin]] || Lateral root formation, maintenance of apical dominance and [https://academic.oup.com/plphys/article/170/2/603/6114063 adventitious] root formation.
|-
| [[Cytokinins]] || Cytokinins regulate root apical meristem size and promote lateral root elongation.
|-
| [[Ethylene]] || Promotes crown root formation.
|-
| [[Gibberellins]] || Together with ethylene, they promote crown primordia growth and elongation. Together with auxin, they promote root elongation. Gibberellins also inhibit lateral root primordia initiation.
|}