Figure 7.

Photobleaching Demonstrates Movement of GFP through a Stromule Connecting Two Chloroplasts in a Hypocotyl Cell of Tobacco Plants Carrying a Nuclear Transgene Encoding Chloroplast-Targeted GFP.

(A) GFP (green) in two chloroplasts with a stromule between was imaged before and during recovery after bleaching of the chloroplast indicated with an arrow.

(B) Chlorophyll autofluorescence (red) before and after photobleaching. Bar = 5 μm.

(C) Change in GFP intensity in the bleached chloroplast and unbleached chloroplast over time indicates decreasing fluorescence in unbleached plastid due to transfer to the unbleached chloroplast, which acquires GFP. A 488-nm argon laser applied at 100% power was used to photobleach GFP. See also Supplemental Movie 6 online.