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Ontogeny of the sheathing leaf base in maize ( Zea mays )
Author(s) -
Johnston Robyn,
Leiboff Samuel,
Scanlon Michael J.
Publication year - 2015
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13010
Subject(s) - primordium , meristem , biology , auxin , zea mays , ontogeny , phyllotaxis , botany , shoot , anatomy , genetics , gene , agronomy
Summary Leaves develop from the shoot apical meristem ( SAM ) via recruitment of leaf founder cells. Unlike eudicots, most monocot leaves display parallel venation and sheathing bases wherein the margins overlap the stem. Here we utilized computed tomography ( CT ) imaging, localization of PIN‐FORMED1 (PIN1) auxin transport proteins, and in situ hybridization of leaf developmental transcripts to analyze the ontogeny of monocot leaf morphology in maize ( Z ea mays ). CT imaging of whole‐mounted shoot apices illustrates the plastochron‐specific stages during initiation of the basal sheath margins from the tubular disc of insertion ( DOI ). PIN 1 localizations identify basipetal auxin transport in the SAM L1 layer at the site of leaf initiation, a process that continues reiteratively during later recruitment of lateral leaf domains. Refinement of these auxin transport domains results in multiple, parallel provascular strands within the initiating primordium. By contrast, auxin is transported from the L2 toward the L1 at the developing margins of the leaf sheath. Transcripts involved in organ boundary formation and dorsiventral patterning accumulate within the DOI , preceding the outgrowth of the overlapping margins of the sheathing leaf base. We suggest a model wherein sheathing bases and parallel veins are both patterned via the extended recruitment of lateral maize leaf domains from the SAM .