2.5 Histochemical Analysis
Histochemical analysis of GUS activity was basically performed as described (Matsuoka, & Numazawa, 1991). Rice tissues were incubated in 90% (v/v) acetone for 30 min and washed three times with PBS. Then, these samples were incubated in the GUS staining solution (50 mM potassium phosphate, 5 mM potassium ferricyanide, 5 mM potassium ferrocyanide, 2 mM 5-bromo-4-chloro-3-indoyl-β-D-glucuronic acid and 0.1% (v/v) Triton X-100) for 3 to 48 h at 37°C. An ethanol wash was performed to stop the GUS reaction and remove chlorophyll from the tissues. These tissues were observed by light microscope or stereoscopic microscope.