Question

Why is the closing of a dandelion flower at dusk not a tropism?

Answer 1

The closing of a dandelion flower at dusk ( when it gets dark ) is not a tropism because the direction of movement of petals of dandelion flower does not depend on the direction of stimulus ( light ) .

Answer 2

The closing of a dandelion flower at dusk is not a tropism because it is a non-directional movement in response to the intensity of light. On the contrary, tropic movement is the movement if the plant parts towards the light. it does not depend upon the intensity of light