Kinetics of upward bending response of gravistimulated snapdragon
shoots
Recording of the gravitropic response
'Simulated time-lapse' photography
In one experiment, 'simulated time-lapse photography' was used to record
the gravitropic response of a quick responding snapdragon shoot obtained
from the University's Matthaei Botanical Gardesn (MGB). Using a standard
camera with a 50 mm lens mounted on a tripod, color slides were taken at
intervals of 15 minutes. The shoots were illuminated during film exposure
by light from a "day light" bulb. During the period with a low bending
rate, e.g. during the initial phase, and after reaching the vertical
position the first time, pictures were taken at longer intervals. After
the top of the shoot had reached its final upright position, the whole
shoot was put back in its original vertical position. The resulting slides
were scanned into a computer and manipulated with the image processing
program, Adobe PhotoshopTM. By overlaying the images a time
lapse-effect could be achieved. The angle of curvature was then measured
by projecting the slides with a projector and using a protractor.
