Response of root system architecture to nutrient availability is
an essential way for plants to adapt to soil environments. Nitrogen
can affect root development either as a result of changes in the
external concentration, or through changes in the internal nutrient
status of the plant. Low soil N stimulates root elongation in maize.
Recent evidence suggests that plant hormones auxin and cytokinin,
as well as NO signaling pathway, are involved in the regulation of
root elongation by low nitrogen nutrition