title: A comprehensive analysis of root morphological changes and nitrogen allocation in maize in response to low nitrogen stress.
abstract: The plasticity of root architecture is crucial for plants to acclimate to unfavourable environments including low nitrogen (LN) stress. How maize roots coordinate the growth of axile roots and lateral roots (LRs), as well as longitudinal and radial cell behaviours in response to LN stress, remains unclear. Maize plants were cultivated hydroponically under control (4 mm nitrate) and LN (40 μm) conditions. Temporal and spatial samples were taken to analyse changes in the morphology, anatomical structure and carbon/nitrogen (C/N) ratio in the axile root and LRs. LN stress increased axile root elongation, reduced the number of crown roots and decreased LR density and length. LN stress extended cell elongation zones and increased the mature cell length in the roots. LN stress reduced the cell diameter and total area of vessels and increased the amount of aerenchyma, but the number of cell layers in the crown root cortex was unchanged. The C/N ratio was higher in the axile roots than in the LRs. Maize roots acclimate to LN stress by optimizing the anatomical structure and N allocation. As a result, axile root elongation is favoured to efficiently find available N in the soil.
authors.affiliation: Key Laboratory of Plant-Soil Interaction, MOE, Center for Resources, Environment and Food Security, College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Gao
authors.forename: Fanjun
authors.initials: F
authors.lastname: Chen
authors.forename: Lixing
authors.initials: L
authors.lastname: Yuan
authors.forename: Fusuo
authors.initials: F
authors.lastname: Zhang
authors.forename: Guohua
authors.initials: G
authors.lastname: Mi
mesh_terms: D018533:Biomass; D018527:Hydroponics; D009566:Nitrates / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development* / Q000502:physiology; D018520:Plant Shoots / Q000254:growth & development / Q000502:physiology; D012987:Soil / Q000737:chemistry; D013312:Stress, Physiological; D003313:Zea mays / Q000254:growth & development* / Q000502:physiology
chemical_list: D009566:Nitrates; D012987:Soil; D009584:Nitrogen
keywords: N status; N utilization; Zea mays L.; aerenchyma; cell length; low nitrogen; root elongation; root thickness