Expression domains of miR165/6, miR165/6-targeted genes, and SPL/NZZ in anthers. A, RNA in situ hybridization showing the expression domains of miR166, REV, PHB, and SPL/NZZ. Ca, Carpel; Msc, microsporocytes; PP, primary parietal cells; PS, primary sporogenous cells; V, vasculature; WT, wild type. White arrowheads show the stomium regions. Asterisks indicate the remnants of shriveled microsporangia. Bars = 20 μm. B, Schematic diagrams indicating the rearranged expression domains of PHB and SPL/NZZ during anther development. IM, Inner microsporangium; LM, Large microsprorangium; OM, outer microsporangium; StR, stomium region.