Question

Given below is an experimental setup to demonstrate a particular tropic movement in germinating seeds. Study the diagram and answer the questions that follow:

1. Label the parts 1 and 2.
2. Name the tropic movement shown by part 1.
3. Part 1 is affected by two stimuli. Name them. Which one of the two is stronger?
4. What is thigmotropism? Give one example.
5. What is meant by 'Positive' and 'Negative' tropic movements in plants?

Answer 1

1. 
   
2. The tropic movement shown in part 1 is Hydrotropism.
3. Part 1 is affected by gravity and water(moisture); water is stronger.
4. The growth movement of plant parts in response to a touch stimulus is called Thigmotropism. Example: Plants such as Sweet Peas, Cuscuta and vines have tendrils that coil around other plants or other available support in response to one-sided contact or touch.
5. Directional movement of a plant part towards the stimulus is called positive tropic movement, and away from the stimulus is called negative tropic movement.