Plant movements include locomotion, where the entire plant or parts move from one place to another, curvature movements where plant parts bend in response to stimuli, and hygroscopic movements in response to moisture changes. Locomotion is seen in unicellular algae and involves ciliary, amoeboid, or cytoplasmic streaming, while curvature movements allow stationary plants to respond to stimuli like light, gravity, temperature and touch through processes like phototropism, geotropism, nastic movements and thigmonasty. Both locomotion and curvature movements are considered vital movements driven by living cells.

1. Plant Movement:
Movement of plants (Fig: 1) are 3 types –
a) Movement of Locomotion
b) Movement of Curvature
c) Hygroscopic Movement
Movement of Locomotion & Movement of Curvature are called Vital movements
because they are developed only living cells or organisms.
Figure-1: Movements of plant.
Movements of Locomotion:
This movements in which whole of plant body or cell or cytoplasm moves from
one place to another place.
These movements are very common among lower plants and mostly
exhibited by unicellular organisms. These movements are relatively faster and
more pronounced.

2. (A) Autonomic Movements of Locomotion:
The spontaneous locomotory movements may be
i) Ciliary Movements: Cilia are the hair-like outgrowth present on
the plasma membrane. This type movement take place due to the
presence cilia or flagella e.g. flagellated bacteria Volvox,
Chlamydomononas , flagellated or ciliated reproductive cell.
ii) Amoeboid Movements: This type of movement is due to
the formation of pseudopodia. Like in Amoeba, amoeboid
movement is seen to capture food.
iii) Cyclosis: It refers to the protoplasmic movement of a
cell. Example- Chara, Hydrilla. The cytoplasm moves
either clockwise or anti-clockwise around a large central
vacuole.
(B) Paratonic or induced Movements of Locomotion or the
Tactic Movements or Taxes:
Tactic movements are movements of locomotion, which are induced by
some unidirectional or one-way external stimuli. Such movement are
called also tactile or taxies. This movement depend on the nature of the
stimuli viz, light or chemical. This movement are termed phototactic,
chemotactic and thermotactic.
i) Phototactic movement or Phototaxis:
Phototaxis is derived from the two words ‘Photo’ meaning light
and ‘Taxis’ meaning the movement of an organism. Certain algae
and there reproductive structure such as zoospores and gametes
are contain light-sensitive ‘eye’ spot.
When these Algal structure receive weak light from one
direction, they move towards the source of light. This is an
example of positive phototactic movement. Example : Volvox,
Chlamydomononas.
A negative phototactic movement means they are away
from source of light. those that have no chlorophyll-containing
pigment in a wide majority can show negative Phototaxis.
Negative Phototaxis is especially helpful to a lot of species. Like for
example, in Earthworm.
ii) Chemotactic Movements or Chemotaxis :
It is the movement of plant or plant parts from one place to
another towards or away from chemical substance. e.g., male

3. gametes of Bryophyta and Pteridophyta move towards archegonia
that secrete sugars, malic acid to attract male gametes.
iii) Thermotactic movements/ thermotaxis:
The growth movement regulated by temperature.
Chlamydomonas move from cold water to medium warm water
and from very hot water to medium temperature.
Movements of Curvature:
The higher plants are fixed to the soil, they cannot move from one
place to another. This type movement occurs only bending or
curvature of some plant part.
(A) Autonomic Movements of Curvature:
(i) Autonomic movements of variation:
It happens in Indian telegraph plant (Desmodium gyrans). The compound leaf
consists of a larger terminal and two smaller lateral leaflets. During day time,
the two lateral leaflets move upward at an angle of 90° and come to lie parallel
to the rachis. Again, they may move downward at 180° & they are parallel to
the rachis. They may again move upward at 90° to come in their original
position. All these movements occur with jerks after intervals, each movement
being completed in about 2 minutes (Figure-2)
Figure-2: Autonomic movements of variation.

4. (ii) Autonomic movements of Growth:
(a) Hyponastic and epinastic movements:
When growth is more on lower surface, petals show curvature on
upper side and ultimately the flower becomes closed. Such type of
movement is called hyponasty (Figure-3).
When the growth is more on upper surface, petals show curvature
on the lower side and ultimately the flower opens. Such movement is
called epinasty (Figure-3).
Figure-3: Hyponastic and Epinastic movements
(b) Nutational: The growth of the stem apices occurs in a zig-zag
manner. The growth of the stem apices occurs in a zig-zag manner. It
is because the two sides of the stem apex alternatively grow more.
Such growth movements are called as nutational movements.
(c) Circumnutational movments: Circumnutational movements
are autonomous. circular movements often exhibited by the tips of
growing plant stems.
(A) Paratonic Movements of Curvature:
This Movement spontaneous movement. The movement arising from
external stimulus is called Paratoni. They are of two types. a) Tropic
movements b) Nastic movements.
Differences between Tropic Movements and
Nastic movements.
Tropic Movements Nastic Movements
1.Growth dependent
movements.
Growth independent
movements.

5. 2. Found in all plants. Found only in a few specialized
plants.
3.It is slow movements. It is quick movements
4.Exampale: Movement of shoot
towards the sunlight.
4. Drooping of the leaves of
Mimosa.
5. Stimuli for the tropic
movements are unidirectional
and never diffused.
5. The stimuli for the nastic
movements may be
unidirectional or diffused.
6.The tropic movements are
related to the direction of
stimuli.
6.The nastic movement are NOT
related to the direction of
stimuli.
Some of Tropic Movements are-
(a) Geotropic movements or Geotropisim :
i)The Tropic movements which take place in response to the gravity
stimulus.
ii)When primary roots grow down into soil are positive geotropic.
Primary stems that grow away from soil (against gravity) are negative
geotropic.
iii) Secondary roots growing at right angles to the force of gravity are
Diageotropic. Secondary lateral roots which grow obliquely downwards
are Plagiogeotropic.
iv) Lateral roots and branches which are not sensitive to gravitational
stimulus are Apogeotropic.
(b) Phototropic movements or Phototropism :
i)The tropical movements response by light stimulus, called
phototropism.
ii) Some of the plant parts such as stems, branches, leaves and pedicels
of flowers move towards the stimulus of light and are said to be
positively phototropic .
iv) Roots and rhizoids which move away from the stimulus of light
are called negatively phototropic.
Some of Nastic Movements or sleep movements are-
(a) Seismonastic movements:
This means a response to touch or shaking. The best example
is Mimosa pudica.

6. (b) Thermonastic or thermonasty movements:
This movement response to temperature. In Crocus the flowers open
at high temperature and close at low temperature.
(c) Photonastic or photonasty movement:
This movement response to light. The opening of leaves and flowers
during daytime and their close at night is an example.
(d) Thigmonastic movement:
This movement response to the touch stimulus of insects. The
movements found in the leaves of Drosera(Figure-3).
Figure-3: Thigmonastic movements.
Written By Abhishek Konar (Botany M.sc)