Nutrients and root development
Nutrients impact root growth & development: Amazing complexity!
Plant nutrients are taken up by roots as ions – mediated by specific transport proteins. The root tips sense their external and internal nutrient concentration in order to adjust root growth and development. The nutrient environment thereby increases or decreases the extent that roots explore the soil.
Nice review by Herrera et al reports that NO3 stimulates elongation of lateral roots, NH4 prompts more lateral formation, P deficiency inhibits primary root growth (but increases root P absorptive capacity). Increase in root/shoot ratio occurs with low P too.
Calcium has well-known impact on root growth and development, but almost exclusively taken up at root tips. Low Ca concentrations will stop root growth and rapidly stunt plant growth.
We’re slowly learning more about the soil-plant interaction, but much of the molecular and biochemical characterization goes over my head (as a soil scientist). Multi-disciplinary approaches are needed to keep improving what happens in farmer fields!