title: Morphogenesis of simple and compound leaves: a critical review.
abstract: The leaves of seed plants evolved from a primitive shoot system and are generated as determinate dorsiventral appendages at the flanks of radial indeterminate shoots. The remarkable variation of leaves has remained a constant source of fascination, and their developmental versatility has provided an advantageous platform to study genetic regulation of subtle, and sometimes transient, morphological changes. Here, we describe how eudicot plants recruited conserved shoot meristematic factors to regulate growth of the basic simple leaf blade and how subsets of these factors are subsequently re-employed to promote and maintain further organogenic potential. By comparing tractable genetic programs of species with different leaf types and evaluating the pros and cons of phylogenetic experimental procedures, we suggest that simple and compound leaves, and, by the same token, leaflets and serrations, are regulated by distinct ontogenetic programs. Finally, florigen, in its capacity as a general growth regulator, is presented as a new upper-tier systemic modulator in the patterning of compound leaves.
authors.affiliation: Department of Plant Sciences, Weizman Institute of Science, Rehovot 76100, Israel.
authors.forename: Idan
authors.initials: I
authors.lastname: Efroni
authors.forename: Yuval
authors.initials: Y
authors.lastname: Eshed
authors.forename: Eliezer
authors.initials: E
authors.lastname: Lifschitz
mesh_terms: D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018398:Homeodomain Proteins / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics / Q000254:growth & development; D018519:Meristem / Q000235:genetics / Q000254:growth & development*; D009024:Morphogenesis; D018532:Pisum sativum / Q000235:genetics / Q000254:growth & development; D010937:Plant Growth Regulators / Q000378:metabolism; D018515:Plant Leaves / Q000033:anatomy & histology / Q000235:genetics / Q000254:growth & development*; D010940:Plant Proteins / Q000378:metabolism
chemical_list: D018398:Homeodomain Proteins; D010937:Plant Growth Regulators; D010940:Plant Proteins