title: Clonal sectors reveal that a specific meristematic domain is not utilized in the maize mutant narrow sheath.
abstract: The narrow leaf and shortened stem phenotypes of the maize mutant narrow sheath (ns) are postulated to result from the lack of founder cell initialization in a region of the meristem that gives rise to leaf and stem margins. To test this model, a lineage map of the maize meristem is presented which compares the development of leaf margins in the narrow leaf mutant, narrow sheath (ns), and wild-type sibling plants. X-irradiation of mature seeds produced aneuploid albino sectors in wild-type and ns mutant plants. Of particular interest are sectors occurring in more than one leaf, which reflect a meristematic albino cell lineage. Analyses of these sectors indicated that: (1) a region of the ns meristem does not contribute to the founder cell population of the incipient leaf; (2) the margins of ns mutant leaves are derived from a lateral region of the meristem different from those in wild-type siblings; (3) founder cells in wild-type, juvenile-staged vegetative meristems encircle the meristem to a greater extent than do founder cells in adult-staged meristems; and (4) meristematic leaf founder cells may be subdivided into specific lateral domains, such that the position of a sector on the meristem correlates with a particular cell lineage. These data support our model for ns gene function in a specific domain of the meristem.
authors.affiliation: Department of Plant Biology, University of California, Berkeley 94720, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Scanlon
authors.forename: M
authors.initials: M
authors.lastname: Freeling
mesh_terms: D018519:Meristem / Q000502:physiology / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D010641:Phenotype; D018515:Plant Leaves / Q000502:physiology / Q000648:ultrastructure; D013045:Species Specificity; D003313:Zea mays / Q000033:anatomy & histology / Q000235:genetics*