This document discusses different types of plant hormones and their functions. It identifies the main plant hormones as auxin, cytokinin, gibberellin, ethylene, and abscisic acid and describes what each regulates, such as cell elongation, growth, ripening, and stress response. It also covers tropisms that direct plant growth in response to stimuli like light, gravity, touch, and water. Photoperiodicity, or the response to day length, influences flowering and is categorized into long day, short day, and neutral day plants.

2. Hormones
•are chemicals
produced by plants
that regulate the
growth processes.

3. Apical Meristem Young Leaves
Growing Seed Developing Plants

4. Plant Branching Pattern

5. The organic molecule made in
one plant that cause an effect
in another part of the plant and
is effective in small
concentration are called plant
hormones.
 Auxin
 Cytokinin
 Gibberellin
 Ethylene Gas
 Abscisic Acid

6. Auxin
• Regulating cell elongation.
• Affects apical dominance; the
inhibition of lateral buds are
meristem.
• These hormones increase plant
growth by stimulating cells to
length and cause to different
shapes.

8. Cytokinin
• A class growth hormones important in
regulation of nuclei aid and protein
metabolism.
• Antagonist to auxin
• are plant hormones that are involved in
cell division, shoot multiplication and
axillary bud proliferation (buds developing
in the leaf axils). They help delay
senescence (aging). If plants are too
spindly, increased cytokinin will help
foster shorter, thicker stems.

10. Gibberellines
• Are a group of plant hormone that, like,
auxin promote plant growth.
• Are effective in stimulating elongination
of internodes, in altering flowering times,
in stimulating fruit development and
growth of laurel buds, and increase cell
invasion.
• Their dramatic action is making
genetically dwarf plant to grow to normal
size.

12. Ethylene Gas
• A simple gas that is made in
small quantities by many plant
tissues.
• It serves as a powerful natural
regulator of growth
development.
• It also promotes the ripening of
the fruits.

14. Abscisic Acid
• A potent inhibitor of seed
germination without being
injurious to the seed.
• Major player in mediating
the adaption of the plant to
stress.

15. Germination is a process by
which a plant grows from a seed.

16. Closing
of
stomata
Protecting cell
from dehydration
Root
growth
Seed maturation
abscission Seedling growth

17. Different Growth
Response
Tropisms

19. Phototropism
•The kind of stimuli
that plants grow
toward or away
from the light.

21. Geotropism or
Gravitropism
•Unequal growth
response to gravity.
•They grow down in the
ground in the direction
of the force gravity.

23. Thigmotropism
•Exhibit uneven
growth in
response to touch.

24. Tendrils

25. Hydrotropism
•Directional growth
in responsewater.

27. Solar tracking or
Heliotropism
•Solar tracking is a
true tropism because
of the orientation of
the light.

29. Nastic Movements
• Usually involves the
movement of leaves.
• Like solar tracking, are
produced by the changes in
turgor pressure in certain
cells in the base of the leaf
petriole.

30. Nyctinastic movement
• Sleep movement
• Leaves or leaflets that
sprayed out in day time,
fold or turn into vertical
position at night.

32. Thigmonastic
•The abrupt response
of plants to touch.
•Similar in principle to
sleep movement.

33. Mimosa Pudica and Venus Flytrap

34. Photoperiodicity
• the response, as affecting growth or repr
oduction, of an organism to
the length of exposure to light in a 24-
hour period.
• The length of night varies with
the location and with the
season.
• The plant responds in a periodic
table manner

35. The response of plants changes in the length of
night can be organize into three categories.
Long day
plants (short
nights)
Plant that begin
the flowering
process before
summer.
Because they
flower only when
the lightening days
reach some critical
length
Short day
plants (long
nights)
Generally after
summer.
Neutral day
Which appears to
be in different to
cycles of light and
darkness.