Developmental Biology

1. Plant
Development

2. A member of the Kingdom
Plantae, a living organism that
utilizes photosynthesis, a process in
which energy from sunlight is
converted to chemical energy
(food). Plants are at the base of
the food web and are autotrophs –
organism that make their own food.
What Is A Plant?

3. Differences Between Plant And
Animal Development
1. Plants do not Gastrulate.
2. Plants have sporic meiosis rather than gametic
meiosis.
3. The life cycle of land plants ( as well as other
plants) includes both diploid and haploid
multicellular stages.
4. Germ cells are not set aside early in
development.
5. Plants undergo extended morphogenesis.
6. Plants have tremendous development plasticity.
7. Plants may tolerate higher genetic loads than
animals.

4. A. Haploid Life Cycle
1. Gametophyte Phase
2. Begins with a haploid spore, produce
gametes by mitotic division and ends with
fertilization producing a diploid zygote
3. Only have one set of chromosomes
B. Diploid Life Cycle
1. Sporophyte Phase
2. Begins from a diploid zygote and produces
haploid spores by meiotic division
3. Having two haploid set of chromosomes

6. Moss Life Cycle
• Moss are heterosporous
– make two distinct types
of spores:
Antheridia – male
gametophyte that
produce sperm by
mitosis
Archegonia - female
gametophyte that
produces eggs by
mitosis
Examples

7. Fern Life Cycle
• Ferns are
homosporous –
produce one type of
spore within a
structure called
sporangium. One
gametophyte can
produce both male
and female sex
organs.
Example

8. Angiosperm gametophytes are associated with
flowers
Development of floral parts ( whorls of
organs of a flower)
1. Sepals – green outer leaf- like structures
present in a circle around the flower
2. Petals – bright showy part of the flower
3. Stamen – male reproductive organ of the
flower that consist of an anther and
filament.
Gamete Production In Angiosperms

9. a. Anther – produces and releases sperm
cells
b. Filament – support the anthers
STAMEN contains the following cells :
Microsporangia (pollen sac)
Microspores –male gametophytes
pollen grains
4. Carpel – female reproductive organs of the
flower that consist of stigma, style and ovary
Stigma – collects pollen
Style – tube that connects the stigma to
the ovary
Ovary – contain and protect the ovule
Ovule- contains eggs for fertilization

10. Pollen grains are very fine usually yellow
dust that is produce by a plant and that is
carried to other plants of the same kind usually
by wind or insects so that plants can produce
seeds
 Consist of two cells:
• Tube cell- will make the tube though the
style to the ovary
• Generative cell- will generate the sperms
cells
 Parts of pollen:
• Exine – outer wall
• Intine – inner wall
Pollen – Male Gametophyte

11. Inside the
anther,
microspore
mother cell
undergo meiosis
to make haploid
microspores
undergoing
mitosis to make
pollen grains in
the stamen
Pollen Development

12. Ovary
 Female
Gametophyte
 Provides
protection for
the developing
embryo
 Develop into a
fruit
 Seeds -fully developed
ovules
 Integuments – outer
layer of ovule develop
into a seed coat

13. Megasporangium- a sporangium that
develops only megaspores
 Megaspores- giving rise to female
gametophyte
Micropyle- a minute opening in the
integument of an ovule of a seed
plant
Integuments – outer layer of ovule
develop into a seed coat

14.  Inside the ovary are ovules
 Megaspore mother cell undergoes
meiosis to make megaspores
 Typically one megaspore survives,
the other disintegrate
 Three rounds of mitosis but only 7
cells are formed
 Endosperm mother cell is prepared
inside the ovule for the sperm
Egg Development

15.  Landing and subsequent
germination of the pollen on
the stigma
 Agents of Pollination
 Wind
 Water
 Insects
 Few birds and animals
Pollination

17. A. Cross pollination – when a flower
is fertilized by another flower
B. Self-pollination – when a flower
fertilised itself
Kinds of Pollination

18.  Complete/ Perfect – contains stamen,
pistil, sepals and petals
Types Of Flowers

19.  Incomplete/ Imperfect – if any part of
the stamen or pistil is missing

20.  Pistillate Flower – flowers containing
functional pistils but no stamen

21.  Staminate Flower – flowers containing
functional stamen and but no pistil

22.  Monoecious
Plants are those
where one plant
has both male
and female
flowers on the
same plant or in
other words one
plant is both
male and female.
Types of Plants

23.  Dioecious –
Plants are
plants where
one plant is
male with only
male flowers
and another
plant is female
with only
female flowers.

24.  Involves the fusion of the male
and female gametes
 Takes place in the ovary
 Pollen lands on the female part
of the flower, and then it
develops a pollen tube and
burrows down to the ovary,
where it fertilizes.
Fertilization

25.  Unique process that involves the
joining of the female gametophyte
with two male gametophyte
 That ultimately becomes the seed
and fruit of the plant
Double Fertilization

26. Covers development from the
time of fertilization until
dormancy occurs
Embryogenesis

27. Formation of the plant embryo
Embryonic Development

29.  Terminal cell- gives rise to the
embryo proper
 Basal cell- gives rise to the
suspensor
 Hypophysis- found at the interface
between the suspensor and embryo
proper
 Suspensor- serves as a nutrient
conduit for the developing embryo
Basic Body Plan Of The Angiosperm During
Embryogenesis

30.  Globular Stage – embryo develops radial
patterning through series of the cell
division
 Aplical layer produce cotyledons
and shoot meristem
 Heart Stage – bilateral symmetry is
apparent
 Torpedo-
 Cotyledonary – embryo complete its
growth by elongating and enlarging

31. Development of a plant from a seed
 Germination requires conditions:
 Oxygen
 Water
 Temperature
 Light
Seed Germination

33. 1. Dermal Tissue ( Epidermis) – form from the
protoderm and contribute to the outer
protective buyers of the plant
2. Ground Tissue (Cortex And Pith) – form from the
ground meristem which lies beneath the
protoderm
3. Vascular Tissue (Xylem And Phloem) – support
and transport water and nutrients
 Procambium – forms at the core of the
embryo that gives rise to the vascular
tissue
Three Tissue System Of The Plant

35. Meristem – composed of actively dividing cells,
responsible for the production of cells.
Kinds of Meristems:
1. Apical Meristem – found at the tip of stems
and roots.
2. Lateral Meristem- aka cambia (singular
cambium), found along the sides of roots and
stem. Increase width or diameter of roots
and stems.
3. Intercalary Meristem- found at the bases of
young leaves and internodes.
Vegetative growth

36. Roots are the non-green underground
descending portions of the plant axis that
give rise to similar types of endogenous
lateral branches growing down into the soil
or water.
The roots functions are:
 Absorption of water and organic
nutrients
 Anchor and support the plant body to
the ground
 Storage of food and nutrients
 Vegetative reproduction
Root Development

38. 1. Leaf Primordial – cluster of cells
that will form leaves
2. Node – union of a leaf and the
stem
3. Internode- stem tissue between
nodes
4. Phyllotaxy- positioning of leaves on
the stem
Shoot Development

41. Establishment of leaves axes
Giving rise to tremendous diversity of leaf
shapes
 Kinds of leaves:
 Simple leaves – have a flat,
undivided blade that is supported
by a stalk called petiole
 Compound leaves- have blades which
are divided into leaflets which
form in one plane and lack axillary
buds.
Leaf Development

43. Plants undergo several developmental
transitions during their life cycle.
Shoot of higher plants passes through 3
more or less distinct phases during its post
embryonic development, and these are:
1. Juvenile Vegetative Phase where the plant is
not competent to flower
2. Adult Vegetative Phase where the plant can
respond to floral inductive signals
3. Reproductive Phase where the flower is
produced to undergo reproduction
Plant Developmental Transition

44. Monocarpic- plants that flower
once and then senesce.
Polycarpic- plants that live
thousands of years and flower
accidentally; death is by
accident
Senescence-developmental Program
Leading To Death Of Plant

45. 1. Histological Studies
2. Culture Experiments
3. InVitroFertilization Experiment
4. Biochemical Analysis
5. Genetic and molecular analyses
of developmental mutants
6. Clonal analysis
Experimental Studies in Plants

46. Different parts of different plants
are capable producing new plants by
themselves. The process of producing
plants through asexual reproduction is
also termed as regeneration. There are
several methods by which plants can be
regenerated such as cutting and grafting.
How Does Asexual Reproduction Take
Place In Plants?

47. Is a method in which a bud is
taken and then grafted onto the root
or the stem of the plant
Grafting

48.  Hormones – Greek term that means
“to excite” , it is a chemical signals
that coordinate the different
parts of an organism
 Plant Hormones – produced by cells
in one area of the plant such as the
leaves, stems or root, and then
transported to a different area of
the plant in order to produce a
response

49.  Hormones produced in immature
parts of plants that stimulate
growth.
 Commonly found in seed embryos,
apical meristem and young leaves.
 Stimulate cell differentiation which
means this hormone helps decide if a
cell will become ground tissue,
vascular tissue or protective tissue.
 Stimulate stem elongation, help
regulate fruit development
Auxins

50.  Produces in the roots
 Stimulate growth and development
of chloroplast responsible for
photosynthesis
 Produce anti- aging effects on
some plant parts for plants to have
healthier look
Cytokinins

51.  Gibberellins
 Produced in meristems of
stems and roots regulate
stem elongation
 Ethylene
 Produced in fruits, flowers
and aging leaves that
promotes fruit ripening

52. 1. Plants are characterized by alternation of
generation- diploid and haploid generations
2. Multicellular diploid sporophyte produces
haploid spores via meiosis .These spores
divide mitotically to produce haploid
gametophyte. Mitotic divisions within the
gametophyte produce the gametes.
3. the male gamete pollen, arrives at the style
of the female gametophyte and effects of
fertilization through the pollen tube. Two
sperm cells move through the pollen tube, one
joins with the ovum to form the zygote ,and
the other is involved in the formation of the
endosperm.
Summary

53. Summary
4.Plant embryos develop deeply
embedded in parental tissue. The
parent tissue provides nutrients but
only minimal patterning information.
5.Early embryogenesis is characterized
by the establishment of the shoot-root
axis and by radial pattern yielding
three tissue systems. Pattern emerges
by regulation of planes of cell division
and the directions of cell expansion,
since plant cells do not move during
development.

54. Summary
6. As the embryo matures, a food reserve is
established. Only the rudiments of the basic
body plan are established by the time
embryogenesis ceases and the seed enters
dormancy.
7.Pattern is elaborated during embryonic
development, when meristems construct the
reiterative structures of the plant.
8.The germ line is not reserved early in
development. Coordination of signaling among
leaves, roots and shoot meristems regulates
the transition to the reproductive state
reproduction may be followed by genetically
programmed senescence of the parent plant.

55. Humankind has not woven the web of
life alone,
We are but one thread within it
Whatever we do to the web,
we do to ourselves
All things are bound together,
All things connect!
Thank You for
listening!!