title: Photosynthetic pathways and ecological distribution ofEuphorbia species in Egypt.
abstract: The photosynthetic pathways of 42 species of the genusEuphorbia growing wild, naturalized or cultivated in Egypt were investigated. The criteria used included the δ13C- and δD-values and Kranz anatomy of the leaves. There is a relationship between the photosynthetic pathway and the ecological conditions in the habitat of a particular species. All 4 CAM species are succulent shrubs, wild or cultivated. The 11 species with C4pathways are mainly summer annuals of tropical origin and flourish under the hot summer conditions. The 27 C3species are either winter annuals, perennials, perennials flourishing in winter or shrubs; the majority are Mediterranean, European or Saharo-Arabian. Summer annuals with C3pathways grow under the shade of the summer crops. Generally, C3plants grow under conditions of relatively better water resources and lower temperature than the C4plants. The majority of the CAM and C4species occur in the southern part of the country, where high temperature is a common feature of the climate.
authors.affiliation: Department of Botany, Faculty of Science, Cairo University, Giza, Egypt.
authors.forename: K H
authors.initials: KH
authors.lastname: Batanouny
authors.affiliation: Institut für Hydrologie, Gesellschaft für Strahlen- und Umweltforschung, Ingolstädter Landstr. 1, W-8042, Neuherberg, Federal Republic of Germany.
authors.forename: W
authors.initials: W
authors.lastname: Stichler
authors.affiliation: Institut für Botanik und Mikrobiologie, Techn. Universität, Arcisstr. 21, W-8000, München 2, Federal Republic of Germany.
authors.forename: H
authors.initials: H
authors.lastname: Ziegler
keywords: Ecological adaptation; Egypt; Euphorbia; Photosynthetic pathways