Figure 4

At MYBR1 promoter drives GUS expression during abiotic stress, floral organ abscission and mechanical wounding. Histochemical localization of GUS activity was performed by staining with X-gluc for different time intervals as described below and in Methods. Panel (A) Significant reduction of GUS expression in leaves after drought stress. However, intense GUS expression in roots was similar to control. (B) A closed flower was opened manually by forceps before GUS staining was performed. (C) A fully opened flower. (B) and (C) No GUS expression was found on pedicel at the point where the sepal, petal and anther join (shown by arrows). (D) and (E) In contrast, intense GUS expression was observed at pedicel connecting sites of floral organs after abscission (arrowheads). (E) A silique fully abscised with floral organs, was stained briefly (2 h) for GUS. Magnification of the connections between floral organs and pedicel shows GUS expression only at attachment sites on pedicel. Panel (F) Leaves were wounded with hemostats. Intense MYBR1 promoter driven GUS expression was observed around the wound relative to control.