The diagram given below represents a plant movement. Answer the following questions: The diagram given below represents a plant movement. Answer the following questions:
Give an example of a plant which shows Thigmotropism.
Topic: Example of thigmotropism
Answer
The PEA PLANT (or any climber with tendrils, such as the grapevine or cucumber), whose tendrils coil around a support on contact.
THIGMOTROPISM is directional growth in response to TOUCH, and the standard example is a TENDRIL coiling round a support.
HOW IT WORKS: where the tendril touches the support, the cells on the side AWAY from the contact grow faster than those touching it, and that unequal growth curls the tendril around.
A CAUTION worth noting: MIMOSA PUDICA (the touch-me-not) is often given as an answer here, but its leaf-drooping is a NASTIC movement, not a tropism — it is not directional and involves a change of turgor rather than growth. A tendril is the safer example.