title: Compound leaf development in the palm Chamaedorea elegans is KNOX-independent.
abstract: OBJECTIVE
  How a leaf acquires its shape is a major and largely unresolved question in plant biology. This problem is particularly complex in the case of compound leaves, where the leaf blade is subdivided into leaflets. In many eudicots with compound leaves, class I KNOTTED1-LIKE HOMEOBOX (KNOX) genes are upregulated in the leaf primordium and promote leaflet initiation, while KNOX genes are restricted to the shoot apical meristem in simple-leaved plants. In monocots, however, little is known about the extent of KNOX contribution to compound leaf development, and we aimed to address this issue in the palm Chamaedorea elegans.
  
  
  METHODS
  We investigated the accumulation pattern of KNOX proteins in shoot apical meristems and leaf primordia of the palm C. elegans using immunolocalization experiments.
  
  
  RESULTS
  KNOX proteins accumulated in vegetative and inflorescence apical meristems and in the subtending stem tissue, but not in the plicated regions of the leaf primordia. These plicated areas form during primary morphogenesis and are the only meristematic tissue in the developing primordium. In addition, KNOX proteins did not accumulate in any region of the developing leaf during secondary morphogenesis, when leaflets separate to create the final pinnately compound leaf.
  
  
  CONCLUSIONS
  The compound leaf character in palms, C. elegans in particular and likely other pinnately compound palms, does not depend on the activities of KNOX proteins.
authors.affiliation: Department of Botany, University of British Columbia, Vancouver, Canada. nowakj@interchange.ubc.ca
authors.forename: Julia S
authors.initials: JS
authors.lastname: Nowak
authors.forename: Nathalie
authors.initials: N
authors.lastname: Bolduc
authors.forename: Nancy G
authors.initials: NG
authors.lastname: Dengler
authors.forename: Usher
authors.initials: U
authors.lastname: Posluszny
mesh_terms: D000918:Antibody Specificity / Q000276:immunology; D028023:Arecaceae / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism* / Q000648:ultrastructure; D018398:Homeodomain Proteins / Q000276:immunology / Q000378:metabolism*; D018515:Plant Leaves / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism* / Q000648:ultrastructure; D010940:Plant Proteins / Q000276:immunology / Q000378:metabolism*; D021381:Protein Transport
chemical_list: D018398:Homeodomain Proteins; D010940:Plant Proteins