Gas film retention and underwater photosynthesis during field submergence of four contrasting rice genotypes.
Floods can completely submerge some rice (Oryza sativa L.) fields. Leaves of rice have gas films that aid O2 and CO2 exchange under water. The present study explored the relationship between gas film persistence and underwater net photosynthesis (PN) as influenced by genotype and submergence duration. Four contrasting genotypes (FR13A, IR42, Swarna, and Swarna-Sub1) were submerged for 13 days in the field and leaf gas films, chlorophyll, and the capacity for underwater PN at near ambient and high CO2 were assessed with time of submergence. At high CO2 during the PN assay, all genotypes initially showed high rates of underwater PN, and this rate was not affected by time of submergence in FR13A. This superior photosynthetic performance of FR13A was not evident in Swarna-Sub1 (carrying the SUB1 QTL) and the declines in underwater PN in both Swarna-Sub1 and Swarna were equal to that in IR42. At near ambient CO2 concentration, underwater PN declined in all four genotypes and this corresponded with loss of leaf gas films with time of submergence. FR13A retained leaf gas films moderately longer than the other genotypes, but gas film retention was not linked to SUB1. Diverse rice germplasm should be screened for gas film persistence during submergence, as this trait could potentially increase carbohydrate status and internal aeration owing to increased underwater PN, which contributes to submergence tolerance in rice.
School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Universitetsparken 4, 3rd floor, 2100 Copenhagen, Denmark.
Anders
A
Winkel
School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia Institute of Advanced Studies, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Universitetsparken 4, 3rd floor, 2100 Copenhagen, Denmark opedersen@bio.ku.dk.
Ole
O
Pedersen
International Rice Research Institute, DAPO Box 7777, Metro Manila, the Philippines.
Evangelina
E
Ella
International Rice Research Institute, DAPO Box 7777, Metro Manila, the Philippines.
Abdelbagi M
AM
Ismail
School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
Timothy D
TD
Colmer
D002245:Carbon Dioxide / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D055868:Floods; D005740:Gases / Q000378:metabolism; D005838:Genotype; D012275:Oryza / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D010788:Photosynthesis / Q000528:radiation effects; D018515:Plant Leaves / Q000378:metabolism / Q000528:radiation effects; D013997:Time Factors
D005740:Gases; D002734:Chlorophyll; D002245:Carbon Dioxide
Aerenchyma; FR13A; IR42; Oryza sativa; SUB1; Swarna; Swarna-Sub1.; flooding stress; leaf air layer; leaf chlorophyll; leaf gas films; leaf hydrophobicity; submergence tolerance; survival