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: Auxin Lateral root formation, maintenance of apical dominance and 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.
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 auxin lateral root formation maintenance of apical dominance and 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