The diagram given below represents a plant movement. Answer the following questions: The diagram given below represents a plant movement. Answer the following questions:
Explain the tropic movement mentioned in (i).
Topic: Definition of chemotropism
Answer
CHEMOTROPISM is the directional growth movement of a plant part in response to the stimulus of a CHEMICAL substance — growth towards the chemical being positive chemotropism, and away from it negative.
A definition of any tropism needs three elements: it is a GROWTH movement, it is DIRECTIONAL, and it names the STIMULUS.
Here the growth is TOWARDS the chemical, so it is POSITIVE chemotropism.
DO NOT CONFUSE tropic with NASTIC movements. A nastic movement is also a response to a stimulus but is NOT directional — the drooping of Mimosa leaves is the same whichever side is touched, and it is a movement of turgor rather than of growth.