title: Reduced photoinhibition with stem curling in the resurrection plant Selaginella lepidophylla.
abstract: Selaginella lepidophylla, the resurrection plant, curls dramatically during desiccation and the hypothesis that curling may help limit bright light-induced damage during desiccation and rehydration was tested under laboratory conditions. Restraint of curling during desiccation at 25° C and a constant irradiance of 2000 μmol m-2s]t-1significantly decreased PSII and whole-chain electron transport and the Fv/Fmfluorescence yield ratio following rehydration relative to unrestrained plants. Normal curling during desiccation at 37.5°C and 200 μmol m-2s-1irradiance did not fully protect against photoinhibition or chlorophyll photooxidation indicating that some light-induced damage occurred early in the desiccation process before substantial curling. Photosystem I electron transport was less inhibited by high-temperature, high-irradiance desiccation than either PSII or whole-chain electron transport and PSI was not significantly affected by restraint of curling during desiccation at 25°C and high irradiance. Previous curling also helped prevent photoinhibition of PSII electron transport and loss of whole-plant photosynthetic capacity as the plants uncurled during rehydration at high light. These results demonstrate that high-temperature desiccation exacerbated photoinhibition, PSI was less photoinhibited than PSII or whole-chain electron transport, and stem curling ameliorated bright light-induced damage helping to make rapid recovery of photosynthetic competence possible when the plants are next wetted.
authors.affiliation: Department of Biology, Vanderbilt University, 37235, Nashville, TN, USA.
authors.forename: Jefferson G
authors.initials: JG
authors.lastname: Lebkuecher
authors.affiliation: Department of Biology, Vanderbilt University, 37235, Nashville, TN, USA.
authors.forename: William G
authors.initials: WG
authors.lastname: Eickmeier
keywords: Desiccation; Photoinhibition; Photooxidation; Selaginella lepidophylla