Question

(a) How does control and coordination take place in plants? How does it differ from that in animals?
(b) Name five stimuli which act on plants. Name the type of tropism produced by each one of these stimuli.
(c) Define hydrotropism. Give one example of hydrotropism. State whether this example is of positive hydrotropism or negative hydrotropism. Illustrate your answer with the help of labelled diagram.

Answer 1

(a) Control and coordination occur in plants with the help of hormones.
It differs from animals because animals have nervous system which is absent in plants.

(b) The five types of stimuli and the tropisms produced by each of them are:

1. Light produces phototropism
2. Water produces hydrotropism
3. Touch produces thigmotropism
4. Chemicals produce chemotropism
5. Gravity produces geotropism

(c) The movement of plant parts in response to water is known as hydrotropism.
An example of hydrotropism is the movement of plant roots towards water. It is a positive hydrotropism because the roots move towards the stimulus.