Combined Effects of Ozone and Drought on the Physiology and Membrane Lipids of Two Cowpea (Vigna unguiculata (L.) Walp) Cultivars
Deborah Moura Rebouças,
Yuri Maia De Sousa,
Matthieu Bagard,
Jose Helio Costa,
Yves Jolivet,
Dirce Fernandes De Melo,
Anne Repellin
Affiliations
Deborah Moura Rebouças
Institut d’Ecologie et des Sciences de l’Environnement de Paris, Faculté des Sciences et Technologie, Université Paris-Est Créteil, 61 Avenue du Général De Gaulle, 94010 Créteil, France
Yuri Maia De Sousa
Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, P.O. Box 6029, 60455-760 Fortaleza, Ceará, Brazil
Matthieu Bagard
Institut d’Ecologie et des Sciences de l’Environnement de Paris, Faculté des Sciences et Technologie, Université Paris-Est Créteil, 61 Avenue du Général De Gaulle, 94010 Créteil, France
Jose Helio Costa
Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, P.O. Box 6029, 60455-760 Fortaleza, Ceará, Brazil
Yves Jolivet
Unité Mixte de Recherche Ecologie et Ecophysiologie Forestières, Université de Lorraine, BP239, F-54506 Vandœuvre-lès-Nancy, France
Dirce Fernandes De Melo
Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Fortaleza, P.O. Box 6029, 60455-760 Fortaleza, Ceará, Brazil
Anne Repellin
Institut d’Ecologie et des Sciences de l’Environnement de Paris, Faculté des Sciences et Technologie, Université Paris-Est Créteil, 61 Avenue du Général De Gaulle, 94010 Créteil, France
The interactive effects of drought and ozone on the physiology and leaf membrane lipid content, composition and metabolism of cowpea (Vigna unguiculata (L.) Walp.) were investigated in two cultivars (EPACE-1 and IT83-D) grown under controlled conditions. The drought treatment (three-week water deprivation) did not cause leaf injury but restricted growth through stomatal closure. In contrast, the short-term ozone treatment (130 ppb 12 h daily during 14 day) had a limited impact at the whole-plant level but caused leaf injury, hydrogen peroxide accumulation and galactolipid degradation. These effects were stronger in the IT83-D cultivar, which also showed specific ozone responses such as a higher digalactosyl-diacylglycerol (DGDG):monogalactosyldiacylglycerol (MGDG) ratio and the coordinated up-regulation of DGDG synthase (VuDGD2) and ω-3 fatty acid desaturase 8 (VuFAD8) genes, suggesting that membrane remodeling occurred under ozone stress in the sensitive cultivar. When stresses were combined, ozone did not modify the stomatal response to drought and the observed effects on whole-plant physiology were essentially the same as when drought was applied alone. Conversely, the drought-induced stomatal closure appeared to alleviate ozone effects through the reduction of ozone uptake.
