Question

When the leaves of a sensitive plant are touched with a finger, they fold up and when light fades at dusk, the petals of a dandelion flower close.

1. State one way in which the above two processes are similar.
2. State two ways in which the above two processes differ.

Answer 1

1. Both processes are similar as the response is not determined by the direction of the stimulus. They are nastic movements.
2. The first process, the folding of leaves, is thigmonastic, and the stimulus is touch. The second process, the closing of petals, is photonastic, and the stimulus is light.