Figure 3.

Phyllotactic defects in the mp meristem and the initiation of leafless domes. A to C, The first leaf primordia in wild-type seedlings (A) and mp mutants (B and C). mp mutants with two opposite cotyledons were used for analysis to preclude any effects of cotyledon placement on subsequent leaf primordia formation. D to I, Wild type (D) and mp mutants (E–I) grown on medium with 10 μm NPA. The cells in the peripheral region of the NPA-grown mp SAM elongate to form a collar of cells (E–I, arrows), which have leaf cell fate as judged by in situ hybridization with an AS1 antisense probe (F). Central region of meristem indicated by arrowheads in G to I. All samples are 2 DAG, except H (4 DAG) and I (9 DAG). Scale bars = 50 μm. [See online article for color version of this figure.]