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).