title: Interactive effects of phosphorus deficiency and exogenous auxin on root morphological and physiological traits in white lupin (Lupinus albus L.).
abstract: White lupin (Lupinus albus) exhibits strong root morphological and physiological responses to phosphorus (P) deficiency and auxin treatments, but the interactive effects of P and auxin in regulating root morphological and physiological traits are not fully understood. This study aimed to assess white lupin root traits as influenced by P (0 or 250 μmol L(-1)) and auxin (10(-8) mol L(-1) NAA) in nutrient solution. Both P deficiency and auxin treatments significantly altered root morphological traits, as evidenced by reduced taproot length, increased number and density of first-order lateral roots, and enhanced cluster-root formation. Changes in root physiological traits were also observed, i.e., increased proton, citrate, and acid phosphatase exudation. Exogenous auxin enhanced root responses and sensitivity to P deficiency. A significant interplay exists between P and auxin in the regulation of root morphological and physiological traits. Principal component analysis showed that P availability explained 64.8% and auxin addition 21.3% of the total variation in root trait parameters, indicating that P availability is much more important than auxin in modifying root responses of white lupin. This suggests that white lupin can coordinate root morphological and physiological responses to enhance acquisition of P resources, with an optimal trade-off between root morphological and physiological traits regulated by external stimuli such as P availability and auxin.
authors.affiliation: Centre for Resources, Environment and Food Security, Department of Plant Nutrition, Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural University, Beijing 100193, China.
authors.forename: Hongliang
authors.initials: H
authors.lastname: Tang
authors.forename: Jianbo
authors.initials: J
authors.lastname: Shen
authors.forename: Fusuo
authors.initials: F
authors.lastname: Zhang
authors.forename: Zed
authors.initials: Z
authors.lastname: Rengel
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D018533:Biomass; D002951:Citrates / Q000378:metabolism; D004347:Drug Interactions; D007210:Indoleacetic Acids / Q000494:pharmacology*; D031297:Lupinus / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology; D010758:Phosphorus / Q000378:metabolism / Q000494:pharmacology*; D010937:Plant Growth Regulators / Q000494:pharmacology; D018517:Plant Roots / Q000033:anatomy & histology / Q000187:drug effects* / Q000502:physiology; D025341:Principal Component Analysis; D011522:Protons; D013997:Time Factors
chemical_list: D002951:Citrates; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D011522:Protons; D010758:Phosphorus; D000135:Acid Phosphatase