Tag: biology

Opening of a bud and drooping of bud are called as epinastic movements. It is well defined as the increased growth of the upper surface of a plant part, such as leaf, resulting in a downward bending of the part.

Seismonasty or thigmonasty is the nastic movement induced in plants where the stimulus is touch. Touch-me-not plant, which has the scientific name as Mimosa pudica is sensitive to touch and is thus called as seismonastic.

The flowers of sunflower open in the morning which is an example of photonasty (regulated by light). Tulip flowers open at high temperature, example of thermonasty (regulated by temperature).

Nastic movements are responses of plant parts to stimuli. Epinasty is the downward bending of a leaf resulting from greater growth of the upper side than of the lower side. Due to more growth on the upper side, the flower will open due to epinasty. The hyponasty is an upward bending of leaves resulting from greater growth of the lower side. Nutation is the bending movements shown by some plant parts due to the unequal rate of growth of different parts of plants. Movement of plant in response to light is called as phototaxis.

Autonomic movement is the spontaneous movement of the protoplasm seen in aquatic plants due to internal stimulus. It is not related to the external stimulus. Movement of cilia and flagella is an example of autonomic movement. A movement shown by a plant part in response to an external factor is called as paratonic movement. In this, the direction of movement is controlled by the direction of the stimulus. Mechanical movements are seen by non-living organs of plants due to hygroscopic changes.

Nastic movements are responses of plant parts to stimuli. Epinasty is the downward bending of a leaf resulting from greater growth of the upper side than of the lower side. Due to more growth on the upper side, the flower will open due to epinasty. The hyponasty is an upward bending of leaves resulting from increased growth on the lower surface.

Tropic movement is growth movement shown by plant in response to a unidirectional external stimulus. Leaves and leaflets shows nyctinastic movement, that is movement in night or in dark. This is also called as sleep movement. In this, the leaves become vertical during night. This is growth movement. Leaf shows daily rhythmic movement due to differential growth of upper and lower halves of the petiole. It is seen in papaya and balsam. 

A movement shown by a plant part in response to an external factor is called as paratonic movement. In this, the direction of movement is controlled by the direction of the stimulus. Autonomic movement is the spontaneous movement of the protoplasm seen in aquatic plants due to internal factors. Growth of plant in response to the current of water is called as rheotropism.

Nastic movements are responses of plant parts to stimuli. Nyctinasty is the rhythmic nastic movement of plant in response to the onset of darkness. Drooping of legume leaves in dark is due to nyctinasty. Seismonastiy is the nastic response of a plant to touch or vibration. Dropping of leaves of Mimosa pudica upon touching is due to seismonasty. 

Nastic movements are responses of plant parts to stimuli. Thermonasty is the a nastic response of plant in response to change in temperature. Thigmonasty or seismonasty is the nastic response of a plant to touch or vibration. Shock movements of leaves of Mimosa pudica leads to dropping of leaves due to seismonasty. Chemonasty is the nastic response of a plant to external chemical.