title: Internal aeration of paddy field rice (Oryza sativa) during complete submergence---importance of light and floodwater O2.
abstract: Flash floods can submerge paddy field rice (Oryza sativa), with adverse effects on internal aeration, sugar status and survival. Here, we investigated the in situ aeration of roots of rice during complete submergence, and elucidated how underwater photosynthesis and floodwater pO(2) influence root aeration in anoxic soil. In the field, root pO(2) was measured using microelectrodes during 2 d of complete submergence. Leaf gas films that formed on the superhydrophobic leaves were left intact, or experimentally removed, to elucidate their effect on internal aeration. In darkness, root pO(2) declined to very low concentrations (0.24 kPa) and was strongly correlated with floodwater pO(2). In light, root pO(2) was high (14 kPa) and primarily a function of the incident light determining the rates of underwater net photosynthesis. Plants with intact leaf gas films maintained higher underwater net photosynthesis relative to plants without gas films when the submerged shoots were in light. During complete submergence, internal aeration of rice in the field relies on underwater photosynthesis during the day and entry of O(2) from the floodwater during the night. Leaf gas films enhance photosynthesis during submergence leading to improved O(2) production and sugar status, and therefore contribute to the submergence tolerance of rice.
authors.affiliation: School of Plant Biology and the UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.|Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Helsingørsgade 51, DK-3400, Hillerød, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Winkel
authors.affiliation: School of Plant Biology and the UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Colmer
authors.affiliation: International Rice Research Institute, DAPO Box 7777, Metro Manila, the Philippines.
authors.forename: Abdelbagi M
authors.initials: AM
authors.lastname: Ismail
authors.affiliation: School of Plant Biology and the UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.|Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Helsingørsgade 51, DK-3400, Hillerød, Denmark.
authors.forename: Ole
authors.initials: O
authors.lastname: Pedersen
mesh_terms: D000064:Acclimatization; D050260:Carbohydrate Metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D055868:Floods; D008027:Light; D012275:Oryza / Q000378:metabolism* / Q000528:radiation effects; D010100:Oxygen / Q000378:metabolism*; D010788:Photosynthesis; D018517:Plant Roots / Q000378:metabolism / Q000528:radiation effects; D018526:Plant Transpiration; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D002734:Chlorophyll; D002245:Carbon Dioxide; D010100:Oxygen