Question

Seismonasty occurs in
(a) Samanea saman
(b) Albizia lebbeck
(c) Hibiscus rosa- sinensis
(d) Mimosa pudica

Answer 1

Hint: This is also known as Makahiya, Sensitive plant, or Touch- me. Leaves of this plant are bipinnately compound, with 1 or 2 pinnaepairs and 10- 26 leaflets per pinna. Pedunculated pale pink or purple flower heads arise from leaf axils.

Complete step by step answer:
Thighmonasty or seismonasty is defined as nasty movement that is caused by the stimulus of touch.
Example: the closing of Mimosa Pudica when touched.
- Hygroscopic movement:
This is the movement of part of a plant that is caused by the influence of the change of the water level from its cells so happens non- homogeneous wrinkling.
- Exogenous movement or etionom/esionom:
It is plant movement that is caused by external stimuli. External stimuli such as, light, gravity, water, touch and chemical substances.
Example:
The breaking of dried Kalanchoe Pinnata fruit.
The opening of sporangium in fern as the cause of wrinkling annulus cells.

- The various kind of exogenous movement in plants:
1) Tropism movement
- Phototropism: It is a tropism movement that is caused by the stimulus of light.
Examples of the tip of plants that lie in the room will bend to the direction of incident of light.
- Geotropism: It is a tropism movement that follows earth gravitational force.
Positive geotropism: The geotropism movement that its direction is downwards.
Negative geotropism: The geotropism movement that its direction is upwards.
- Chemotropism: Tropism movement that is caused by the action of chemical substances stimulus.
Example: The movement of roots toward the presence of fertilizer in the soil.
- Hydrotropism: It is the movement of the plant root that is influenced by reservation of soil water.
2) Nastic movement
Nastic movement: In this plant movement to stimulus, that its direction is not determined by stimulus but by plant itself. Kinds of nastic movements:
- Photonasty : Nasty movement caused by the stimulus of light.
Example: The opening of Mirabilis Jalapa flower at a certain time.
- Nictinasty : Nasty movement that is caused by dark conditions.
Example: The closing of compound leaves of Leucaena Leucocephala during night.
- Thigmonasty: Nasty movement that is caused by the stimulus of touch.
Example: the closing of Mimosa Pudica when touched
- Thermonasty: The nasty movement that is caused by temperature stimulus.
Example: tulip flowers will bloom if the temperature rises.
- Complex nasty: The nasty movement caused by several factors all together.
Example: The opening and closing of stomata is influenced by light, chemical substances , and water.
3) Taxis movement
Transfer of movement of all parts of plants to stimulus that its direction is determined by stimulus. The different kinds of taxis movements:
- Photo taxis: Taxis movement that is caused by the stimulus of light.
Example: The movement of the chlorophyll to the surface of the leaves to absorb the light.
- Chemotaxis: Taxis movement that is caused by chemical substance stimulus.
Example: The movement of spermatozoa of moss and fern to ovum that is found in archegonium attached to the sugar or protein that is produced by archegonium .
So, the correct answer is, ‘(d) Mimosa pudica.’

Note:
- Endogenous movement (autonomic)
It is a movement that is not known yet but it is caused suddenly but predicted that this motion is caused by stimulus that comes from the body of the plant itself.
Example:
The flowing movement of cytoplasm in the cell.
The blending movement of leaf bid because of the difference of growth velocity.