Stomatal aperture treatment
Leaves were detached from 2-month-old WT and oxPtrWRKY75 plants, perforated at the same position on both sides of the main vein with a perforator, and immersed under light in stomata-opening solution containing 0.01 M KCl, 0.5 M CaCl2, and 0.1 M MES-KOH for 2 h. The leaves were soaked in aqueous SA solution (0.5 mM) for 0, 1, or 2 h, as described by Wang (2016). The fixed samples were immediately frozen in liquid nitrogen and stored in a −80 °C Ultra-low Freeze Dryer (Biosafer-18A, Jiangsu, China (Mainland)) and fully dried for 24 h using a vacuum freeze dryer. The stomata were examined under a scanning electron microscope (Hitachi S-3400N, Tokyo, Japan).