Progression of stomatal development on gynoecial and silique valves.

(A) Example stomatal lineage cells used to define early, mid, and late stages of stomatal development for morphological analysis (not to scale). Cells of the stomatal lineage are distinguished based on the presence of an asymmetric cell division and/or presumed early stage GMCs (Early stage), the rounding of a cell similar to a GMC (Mid stage), and the presence of a symmetric cleavage (Late stage). (B-E) Scanning electron micrographs of gynoecia at floral stage (B) 12, (C) 13, (D) 15–16 gynoecia and (E) a stage >17 silique with magnifications of the cell surface (from white box). Scale bars for images of whole gynoecia are 100 μm. Scale bars for magnifications are 20 μm. Purple, blue, and red highlights indicate early, mid, and late stage stomatal lineage morphology, respectively. (F-H) Levels of AG and SEP3 mRNAs over the course of (F) flower development determined by microarray analysis [42] and (G) gynoecium development determined by laser-capture microdissection combined with RNA-Seq [43] and (G) gynoecium development determined by RT-qPCR. (I) Levels of SPCH, MUTE, and FAMA mRNAs during gynoecium development determined by RT-qPCR. Error bars in (F-I) are s.e.m of (F-G) three and (H-I) four independent biological replicates, respectively. M, log-ratio of time-point to a reference; TPM, transcripts per million. Expression in (H-I) was normalized to the average of late stage 11/early stage 12 gynoecia time-point.