Optical Trapping in Plant Cells - Plant Cell Morphogenesis: Methods and Protocols - page 253

Fig. 2 Moving a trapped, unidentifi ed organelle into the vacuolar lumen by relocating the position of the optical
tweezers causes the formation of a cytoplasmic strand that acquires ER. The arrows indicate the position of
the tweezers in the Nomarski images, and the arrowhead points to the ER that has appeared in the tweezers-
formed strand after 10 s. The fi rst row of images shows the confocal fl uorescence images, the second row the
Nomarski images, and the third row a merge of the upper two rows in which the fl uorescence image is dis-
played in green . Bar: 10 μ m

apertures, we were not able to trap structures within plant cells.
During the trapping experiments, the IR-laser power was varied
between 25 and 100 %, which corresponds to a laser intensity in
the sample that lies in the 25-130 mW range. Several consider-
ations for sample preparation are given below. As an example of a
typical imaging sequence, we have included three images taken
from a time series in which an unidentifi ed organelle is trapped in
a Tobacco BY-2 cell expressing the live cell ER marker HDEL-
GFP. When the organelle is moved into the vacuolar lumen, a
tweezers-formed cytoplasmic strand is produced that is surrounded
by a tonoplast membrane. This particular experiment shows that an
ER strand rapidly appears in the tweezers-formed strand (Fig. 2 ).