Fig. 4. Whole mounts of excised quiescent centers (QC), with and without the adjacent proximal meristem (PM), from roots pre-treated for 2-3 hours with the redox sensitive dye carboxy H2DCFDA. C-J are from roots exposed to NPA (for 24 or 48 hours), and then either treated with the dye, or allowed to grow for an additional amount of time, with no NPA, and then treated with the dye. (A,B) Control, no NPA. Photographed in white light only (A) or in white +UV (B). (C,D) QC at the end of the 24-hour NPA treatment. Photographed in white light (C) or in UV (D). The extent of fluorescence has decreased relative to the control (B). (E-H) QCs and a PM from roots allowed to grow for 24 hours after the end of the NPA treatment. Photographed in white light (E,G), or in UV (F,H). At this time QCs show variable fluorescence. The PMs essentially show no fluorescence (F). G and H are from a QC showing essentially no fluorescence. (I,J) QC and adjacent PM from roots at the end of a 48-hour NPA treatment. Photographed in white (I) or in UV light (J). Note that the PM region is now highly fluorescent, with no fluorescence in the QC. Scale bar, 100 µm.

Return to article