title: Spatio-temporal patterns in rhizosphere oxygen profiles in the emergent plant species Acorus calamus.
abstract: Rhizosphere oxygen profiles are the key to understanding the role of wetland plants in ecological remediation. Though in situ determination of the rhizosphere oxygen profiles has been performed occasionally at certain growing stages within days, comprehensive study on individual roots during weeks is still missing. Seedlings of Acorus calamus, a wetland monocot, were cultivated in silty sediment and the rhizosphere oxygen profiles were characterized at regular intervals, using micro-optodes to examine the same root at four positions along the root axis. The rhizosphere oxygen saturation culminated at 42.9% around the middle part of the root and was at its lowest level, 3.3%, at the basal part of the root near the aboveground portion. As the plant grew, the oxygen saturation at the four positions remained nearly constant until shoot height reached 15 cm. When shoot height reached 60 cm, oxygen saturation was greatest at the point halfway along the root, followed by the point three-quarters of the way down the root, the tip of the root, and the point one-quarter of the way down. Both the internal and rhizosphere oxygen saturation steadily increased, as did the thickness of stably oxidized microzones, which ranged from 20 µm in younger seedlings to a maximum of 320 µm in older seedlings. The spatial patterns of rhizosphere oxygen profiles in sediment contrast with those from previous studies on radial oxygen loss in A. calamus that used conventional approaches. Rhizosphere oxygen saturation peaked around the middle part of roots and the thickness of stably oxidized zones increased as the roots grew.
authors.forename: Wenlin
authors.initials: W
authors.lastname: Wang
authors.affiliation: Jiangsu Key Laboratory of Environmental Change and Ecological Construction, College of Geographical Science, Nanjing Normal University, Nanjing, China; Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, Nanjing, China.
authors.forename: Wang
authors.initials: W
authors.lastname: Wenlin
authors.forename: Ruiming
authors.initials: R
authors.lastname: Han
authors.affiliation: Jiangsu Key Laboratory of Environmental Change and Ecological Construction, College of Geographical Science, Nanjing Normal University, Nanjing, China.
authors.forename: Han
authors.initials: H
authors.lastname: Ruiming
authors.forename: Yinjing
authors.initials: Y
authors.lastname: Wan
authors.affiliation: Jiangsu Environmental Engineering Consulting Center, Nanjing, China.
authors.forename: Wan
authors.initials: W
authors.lastname: Yinjing
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.affiliation: Jiangsu Key Laboratory of Environmental Change and Ecological Construction, College of Geographical Science, Nanjing Normal University, Nanjing, China; School of Geography Science, Nantong University, Nantong, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Bo
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Tang
authors.affiliation: Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, Nanjing, China.
authors.forename: Tang
authors.initials: T
authors.lastname: Xiaoyan
authors.forename: Bin
authors.initials: B
authors.lastname: Liang
authors.affiliation: Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, Nanjing, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Bin
authors.forename: Guoxiang
authors.initials: G
authors.lastname: Wang
authors.affiliation: Jiangsu Key Laboratory of Environmental Change and Ecological Construction, College of Geographical Science, Nanjing Normal University, Nanjing, China.
authors.forename: Wang
authors.initials: W
authors.lastname: Guoxiang
mesh_terms: D029023:Acorus / Q000502:physiology*; D010100:Oxygen / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism; D058441:Rhizosphere; D036226:Seedlings / Q000254:growth & development* / Q000378:metabolism; D062211:Spatio-Temporal Analysis; D053833:Wetlands
chemical_list: D010100:Oxygen