title: A novel pattern of leaf movement: the case of Capparis spinosa L.
abstract: A novel type of heliotropic leaf movement is presented for Capparis spinosa L., a summer perennial shrub of Mediterranean and arid ecosystems. In contrast to plants that demonstrate uniform diaheliotropic and/or paraheliotropic movement for all their foliage, the alternate leaves of C. spinosa follow different movement patterns according to their stem azimuth and the side of the stem that they come from (cluster). Additionally, leaf movement for each cluster may not be uniform throughout the day, showing diaheliotropic characteristics during half of the day and paraheliotropic characteristics during the rest of the day. In an attempt to reveal the adaptive significance of this differential movement pattern, the following hypotheses were tested: (i) increase of the intercepted solar radiation and photosynthesis, (ii) avoidance of photoinhibitory conditions, (iii) amelioration of water-use efficiency and (iv) adjustment of the leaf temperature microenvironment. No evidence was found in support of the first two hypotheses. A slight difference toward a better water use was found for the moving compared with immobilized leaves, in combination with a better cooling effect.
authors.affiliation: Department of Agriculture Crop Production and Rural Environment, University of Thessaly, 38446 Volos, Greece.
authors.forename: Efi
authors.initials: E
authors.lastname: Levizou
authors.affiliation: Laboratory of Botany, Department of Biological Applications and Technology, University of Ioannina, 45110 Ioannina, Greece akypar@cc.uoi.gr.
authors.forename: Aris
authors.initials: A
authors.lastname: Kyparissis
mesh_terms: D000222:Adaptation, Physiological; D031484:Capparis / Q000502:physiology*; D009068:Movement; D010788:Photosynthesis; D018515:Plant Leaves / Q000502:physiology*; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water
keywords: caper; heliotropic leaf movement; light-use efficiency; photoinhibition; photosynthesis; water-use efficiency