The topic "Coordination in Plants" contains Nastic and Tropic movements in plants and phytohormones for class X CBSE and other board students.

2.  All living organisms respond to environmental stimuli.
 Animals have nervous system and endocrine system for
control and coordination.
 Plants also respond to stimuli by secreting chemicals.
 Plants exhibit some movements.

3. Movements
of Plants
Directional
or Tropic
movements
Non-directional
or Nastic
movement
Occur in the
direction of the
stimulus
Non growth
movement,
independent of
stimulus

4.  The movements do not
depend on the direction
from the stimulus acts.
 Example - when someone
touches the leaves of
mimosa, the leaves begin to
fold up and droop.

5. Leaves before touching Leaves after touching

6.  The drooping of Mimosa leaves
is independent of the direction
from which the leaves are
touched.
 Such movements usually
happen due to change of water
balance in the cells.
 When leaves of mimosa are
touched, the cells in the leaves
lose water and become flaccid
which results drooping of
leaves.

7.  Plants respond to stimuli
slowly by growing in a
particular direction.
 Example - Plants like the
pumpkin, cucumber etc.
plant climb up fences by
means of tendrils.

8. Types of Trophic movements
Phototropism (light)
Geotropism (gravity)
Hydrotropism (water )
Chemotropism (chemicals)
Thigmotropism (touch)

9.  Phototropism is the growth
of plants in response to light.
 Positive phototropism –
Shoots respond by bending
towards light.
 Negative phototropism -
Roots respond by bending
away from light.
Phototropism
Response of the plant to
the direction of light

10. Geotropism
 Geotropism is the
movement of a plant in
response to gravity (either
downwards or upwards).
 Positive geotropism – Roots
grow towards the ground
 Negative geotropism -
Shoots by growing away
from the ground.
Plant showing Geotropism

11. Hydrotropism
 Hydrotropism is a growth
response in which the
direction is determined by
the stimuli of water.
 Example - Roots grow
towards the source of water.
Plant showing
Hydrotropism

12.  Chemotropism is a
growth movement of a
plant part in response to
chemical stimulus.
 Example - Growth of
pollen tubes towards
ovules
Flower showing
Chemotropism

13.  Thigmotropism is the
directional growth of a
plant part in response to
the touch stimulus of an
object.
 Climbers produce tendrils
which move towards a
source of support in order
to coil around it and help
the plant to climb.
Thigmotropism
Plant showing
Thigmotropism

14.  Plants hormones, also called Phytohormones, are
chemicals produced within the plant in a low
concentrations and diffuse all around the cell.
 Phytohormones regulate plant growth,
development and response to the environment.

15. Types of Phytohormones
Auxins
Gibberellins
Cytokinins
Abscisic acid
Ethylene

16.  Auxins are synthesised by the growing apices of the stem
and root.
 It promotes cell elongation and growth of stem and root.
 It causes apical dominance.
 It induces rooting on stem cutting.
 Gibberellins are hormones that help in the growth of
the stem, seed germination, bolting, and flowering.
 It induces parthenocarpy.
 It’s application overcomes the genetic dwarfism.
 It breaks up the dormancy of seeds.

17. Cytokinins are hormones present in the areas of rapid
cell division, such as fruits and seeds.
 It promotes cell division and cell enlargement.
 It promotes the germination of seeds.
Abscisic acid is a hormone that inhibits the growth in
various parts of plants.
 It inhibits cell growth and cell division.
 It causes dormancy of buds and seeds.
 It induces wilting of leaves and closure of stomata.
Ethylene is a gaseous plant growth regulator.
 It plays role in ripening of fruits.