摘要 : Gas films on hydrophobic surfaces of leaves of some wetland plants can improve O₂ and CO₂ exchange when completely submerged during floods. Here we investigated the <i>in situ</i> aeration of rhizomes of cord... 展开 Gas films on hydrophobic surfaces of leaves of some wetland plants can improve O₂ and CO₂ exchange when completely submerged during floods. Here we investigated the <i>in situ</i> aeration of rhizomes of cordgrass (<i>Spartina anglica</i>) during natural tidal submergence, with focus on the role of leaf gas films on underwater gas exchange. Underwater net photosynthesis was also studied in controlled laboratory experiments. In field experiments, O₂ microelectrodes were inserted into rhizomes and pO₂ measured throughout two tidal submergence events; one during daylight and one during night-time. Plants had leaf gas films intact or removed. Rhizome pO₂ dropped significantly during complete submergence and most severely during night. Leaf gas films: (1) enhanced underwater photosynthesis and pO₂ in rhizomes remained above 10 kPa during submergence in light; and (2) facilitated O₂ entry from the water into leaves so that rhizome pO₂ was about 5 kPa during darkness. This study is the first <i>in situ</i> demonstration of the beneficial effects of leaf gas films on internal aeration in a submerged wetland plant. Leaf gas films likely contribute to submergence tolerance of <i>S. anglica</i> and this feature is expected to also benefit other wetland plant species when submerged.Digital Object Identifier http://dx.doi.org/10.1111/j.1365-3040.2011.02405.x 收起