title: Photosynthetic pathways, distribution, and ecological characteristics of grass species in egypt.
abstract: This study is based both on our own results, especially δ13C analyses, and on data in the literature. Of the 225 species of Poaceae reported from Egypt, 105 species show the C3and 120 the C4type of photosynthetic CO2fixation. Winter annual and perennial grasses active in winter are mainly C3species, while summer annuals and the other perennials are mainly C4species. The percentage of C3species decreases with decreasing latitude. This seems to be mainly related to increasing temperatures. The C3grass species are found preferentially in the Mediterranean, Irano-Turanian, Mediterranean/Irano-Turanian, and Saharo-Arabian chorotypes, while the C4species are mainly found in the Sudanian, Saharo-Arabian/Sudanian and Tropical chorotypes. In Egypt, the NADP+-ME and NAD+-ME subtypes of C4photosynthesis are found in about equal numbers of C4species, while the PCK subtype is relatively rare.
authors.affiliation: Faculty of Science, University of Cairo, Giza, Egypt.
authors.forename: K H
authors.initials: KH
authors.lastname: Batanouny
authors.affiliation: Institut für Hydrologie der Gesellschaft für Strahlen- und Umweltforschung München, Ingolstädter Landstrasse 1, D-8042, Neuherberg, Federal Republic of Germany.
authors.forename: W
authors.initials: W
authors.lastname: Stichler
authors.affiliation: Institut für Botanik und Mikrobiologie der Technischen Universität, Arcisstrasse 21, D-8000, München 2, Federal Republic of Germany.
authors.forename: H
authors.initials: H
authors.lastname: Ziegler
keywords: C4 subtypes; Chorotypes; Grass species; Photosynthetic pathways; Phytogeographical zones (Egypt)