Cambridge O Level Biology · Syllabus 5090 · Coordination and Response in Plants
Bending Angle
What is Bending Angle?
The angle between the original orientation of a shoot and its orientation after a period of growth, measured in degrees from a marked starting position. It is the usual quantitative measure of a tropic response, and it is meaningful only when the starting orientation, the time interval and the measuring method are all stated.
This definition is part of the Coordination and Response in Plants chapter in Cambridge O Level Biology.
Questions students ask about Bending Angle
How do you investigate phototropism in shoots?
Grow similar seedlings in light-proof boxes, with a hole in one side of the treatment box so light enters from one direction only, and a control lit evenly from above or rotated regularly. Control species, age, initial shoot length, water, growth medium, temperature, lamp distance, duration and starting orientation. After a fixed time, measure the bending angle in degrees from the marked starting orientation for several seedlings and compare the means.