Sexual Reproduction in Plants

1. SEXUAL
REPRODUCTION IN
PLANTS

2. Sexual reproduction is the
formation of new organisms from
parent cells that have undergone
meiosis,gamete formation,and
fertilization.A number of single-
celled organisms such as animals
and plants undergo this
reproduction method.And in
plants,sexual reproduction centers
on the flower.

3. A flower has four major
parts,namely,the pistils,stamen,petals,and
sepals.These parts are borne on the broad tip of a
flower-bearing stem called receptacle.
However,not all flowers contain all these
parts.In some species,the sepals,petals,or both
seplas and petals,may be lacking.In other
flowers,only the stamen and pistil may be
present.Flowers with all four parts are said to be
complete,while those that do not have all these
parts are called incomplete.
PARTS OF A FLOWER

4. REPRODUCTIVE PARTS
Of the major parts of a
flower,two are used for
reproduction.These are the
stamen and the pistil.Both
organs undergo development
and maturation.

5.  STAMEN-is the male reproductive structure and
consists of the anther and the filament.
 ANTHER-is the fertile part of the stamen that is
responsible for the production of the sticky powder
called pollen.
 FILAMENT-along thredlike stalk.
 PISTIL-is the female reproductive structure and
consists of the stigma,style, and ovary.
 STIGMA-is the bulb that is found in the center of
most flowers.It receives the pollen grains that then
germinate in this part.
 STYLE-is the long stalk to which the stigma is
attached.
 OVARY-it contains the ovules.
 OVULES-or the seed that turn into fruit.
 PETALS-are the colorful and attractive parts of the
flower.
 SEPALS-are the outer and green leaflike parts that
enclose a developing bud of a flower.

6. PARTS OF A FLOWER

7. POLLINATION
Pollination is the transfer
of the pollen from the anther to
the stigma.It is a very important
process because it results in
the production of new seeds
from which new plants grow.

8. KINDS OF POLLINATION
There are two kinds of pollination:
SELF-POLLINATION-is the transfer
of pollen from yhe anther of one
flower to the stigma of another
flower of the same plant.
CROSS-POLLINATION-is the transfer
of pollen from the stamen of a
flower of a plant to the pistil of a
flower of another plant of the same
species.

9. SELF-POLLINATION

10. CROSS-POLLINATION

11. AGENTS OF POLLINATION
Human
Animal
Wind

12. AGENTS OF POLLINATION
Animals
Human
Wind

13. ASEXUAL
REPRODUCTION IN
PLANTS

14. The asexual reproduction is
the reproduction method that does
not involve sex cells or gametes,
and an organism is formed from a
single parent.This type of
reproduction is common in plants
and unicellular organisms but
rarely in animals.

15. PLANT PARTS USED IN ASEXUAL
REPRODUCTION
Any part of a plant-
flower,fruit,leaf,stem, or roots can be
used for asexual reproduction under
the right conditions.However,the stem
is the part that is most commonly
used.

16. PART OF THE PLANT THAT USE IN
REPRODUCTION

17. You have learned that among the primary
functions of a stem is to provide the plant with
support.It is also the part that serves as
passageway for the transport of fluids from the
roots to other parts of the plants.It also stores
nutrients for plant.Stems,either growing above or
under the ground,can also be used to produce
plants asexually.For example ,strawberry plants
are connected by a horizontal stem called stolon
.In between stolons is a node where the new
strawberry plant is formed.
Other stems are also used to develop
new plants through asexual reproduction.These
include the rhizomes of ginger,bulbs of
onion,corns of gabi,and potato tubers.

18. STOLON

19. METHODS OF ASEXUAL
REPRODUCTION IN PLANTS
Some plants of commercial
importance are propagated through
asexual reproduction to retain their
desirable traits such as flavor,flower
color,medical value ,and resistance to
disease.Among the methods that can
be used are
cutting,grafting,budding,layering, and
tissue culture.

20. METHODS OF ASEXUAL
REPRODUCTION IN PLANTS

21. CUTTING
Cutting involves taking a branch from a parent
plant.The cut branch can then be planted directly in soil or
soaked first in water with root-stimulating hormones before
it is planted.This method is both easy and
inexpensive.Cassava or kamoteng kahoy (Manihot
esculenta), as root crop and an excellent source of
carbohydrates for animals and humans,is one of the plants
reproduced using this method.Another value crop that is
propagated using this method is sugar cane (Saccharum
officinarum).
Related to teh method of cutting is
fragmentation,wherein apart of the parent plant is broken
off then grows into a new plant.Cutting involves an
international break of the part from the parent plant for
purposes of reproduction.Fragmentation implies that the
part is detached from the parent plant by other means such
as wind.

22. CUTTING

23. GRAFTING
Grafting is the form of
asexual reproduction in which the
scion,or a root or twig cut from the
parent plant,is inserted into the
stock,or the lower part of the parent
plant.the scion is usually cut from the
upper part of the parent plant.Both
the scion and stock belong to the
same plant species.This method is
widely used to propagate a variety of
shrubs and trees.

24. GRAFTING

25. In budding,the parent plant
produces an out growth that
becomes bigger until it breaks off
from the parent plant and forms a
new plant.Potatoes reproduce
through this method,as buds form
from "eyes" that develop on the
parent plant.
BUDDING

26. BUDDING

27. LAYERING
With layering,a branch
of the plant is bent over and
pinned to the spot where the
new plant is expected to
grow.When roots develop on
the spot,the plant is then
"unpinned."

28. Following are some common
types of this method:
1.Simple layering-This is done by
bending a stem about 15.24 cm to 25.4
cm above the ground and covering
that bent part with soil.A stake may be
placed on the bent part keep it in
place.New roots will develop from the
bent stem after a few days or
weeks.This type of propagation works
well with low-lying plants.

29. SIMPLE LAYERING

30. 2.Tip layering-This is similar to
simple layering.This is done by
placing the tip of a plant in a hole
that is 10.16 cm deep in the ground
and covering it with soil.The tip will
grow down then up,allowing the
roots to form at the spot where the
plant will spurt upward.

31. TIP LAYERING

32. 3.Air layering- This is popularly
known as marcotting,and is done
by removing part of the bark of a
tree,covering the exposed part
with soil or moss before wrapping
with cellophane of foil,then tying
it in place.When roots grow in the
moss,the new plant is then cut off
and replanted.

33. AIR LAYERING

34. As its name implies,the tissue culture
method makes use of plant tissue samples such as leaf
stem.The surface of a leaf stem can be scraped or cut
thinly into small pieces and transferred to a sterile
agar-based growth medium.The scraped or thinly cut
tissue samples are cultured for a certain period of time
until these grow into small plants or plantlets.The
plantlets are then removed and transferred to pots or
soil beds.These steps make tissue culture more
expensive and difficult to do than reproduction through
the use of cuttings.Thus,this technique is generally
used to propagate under natural enviromental
conditions.An example is the BT corn plant,a
genetically modified organisms (GMO) produced at the
National Institute of Biotechnology and Microbiology in
Los Baňos,Laguna.
TISSUE CULTURE

35. TISSUE CULTURE

36. SEXUAL
REPRODUCTION IN
ANIMALS

37. Sexual reproduction in animals
takes place through two
methods:conjugation and syngamy.
Conjugation is the temporary
sexual union of two or more cells or
organisms where they share genetic
material through a cytoplasmis
bridge.When thr transfer is
completed,the two cells or organisms
voluntarily separate.Conjugation is
considered a primitive form of sexual
reproduction for lower forms of
animals such as paramecium.

38. CONJUGATION

39. On the other
hand,syngamy,which is also called
fertilization,is the permanent union
of egg and sperm cells.It occurs in
higher forms of animals.Humans
and other vertebrates,especially
mammals,udergo syngamy.The
reproductive organs of these
animals are collectively referred to
as gonadsor ,specifically,testis in
males and ovaries in females.

40. SYNGAMY

41. INTERNATIONAL AND
EXTERNAL FERTILIZATION
Animals exhibit two
patterns for bringing their
sperm and egg cells
together.These are through
internal and external
fertilization.

42. With internal
fertilization,the fertilized egg
stays in its mother's womb for a
set number of days.Even while in
the womb,it receives adequate
nourishment from its mother.It
also assured of protection while
in the womb.Humans and higher
forms of vertebrates like
mammals are fertilized in this
manner.

43. INTERNAL FERTILIZATION

44. With external fertilization,most of the eggs
that the mother has released are fertilized by sperm
cells released by the male.The sperm cells travel to
the eggs usually through water.Both the female and
the male release a big number of egg and sperm
cells,respectively.This natural mechanism of survival
ensures that a big number of eggs will be fertilized
by the sperm.Unlike in internal fertilization,the
female does not have to nourish the eggs it
released.The eggs have enough nutrients to supply
the growing embryo.The fertilized eggs develop and
transform until the offspring are fully grown.External
fertilization lasts for a shorter term than internal
fertilization.Examples of organisms that are bred
through external fertilization are fishes and frogs.

45. EXTERNAL FERTILIZATION

46. EXAMPLE OF ORGANISMS
THAT REPRODUCE
THROUGH ITS METHOD

47. REPRODUCTION IN
HUMANS

48. In the reproduction
process of humans,the
fertilized egg,which is called
zygote,goes though embryo
development before it is
ready for birth.

49. EMBRYO DEVELOPMENT
In humans,the newly formed
zygote divides into two cells in the
upper portion of the fallopian tube.The
fallopian tube is one of a pair of
narrow tubes that are located in the
female's abdominal cavity and that
serve as passageways for the sperm
cell to move to the egg that is in the
uterus.The uterus is a pear-shaped
muscular organ in whicj the fertilized
egg stays and is nourished until it
reaches maturity.

50. After about four days in the
fallopian tube,the fertilized egg
goes down the uterus at the rate of
about 2 1/2 cm per day.It will take
about four days for the egg to
travel down the tube into the
uterus.Once the fertilized egg is
implanted in the uterus,pregnancy
has been achieved and the egg is
now called embryo.

51. PARTS OF HUMAN REPRODUCTION
SYSTEM (FEMALE)

52. In the uterus,the mass of
around 32 cells that were formed in
the zygote becomes differentiated
into the blastula.The blastula has
two germ layers:the outer layer
called ectoderm and the inner layer
called endoderm.These layers form
the embryonic disk,which,in
turn,later form the fetus.A middle
layer called mesoderm is also
develops at a later time.

53. BLASTULA

54. ECTODERM

55. ENDODERM

56. MESODERM

57. The primary germ layers give
rise to the major organ systems of the
new individual.The ectoderm forms
the new individual's
skin,hair,nails,skin glands,nasal and
mouth cavities,tooth enamel,central
and peripheral nervous systems,and
linings of all the sense organ.The
endodern gives rise to a portion on
the pituitary gland,the respiratory
system,and the linings of the digestive
system as well as of the liver and
pancreas.The mesoderm forms the
muscles,bones,blood
vessels,kidneys,gonads,and part of
the glands.

58. Pregnancy normally lasts for
nine months before the baby is
born.During this period,the embryo
is initially nourished by the
products of the breakdown of the
inner lining of the uterus called
endometrium during implantation of
the fertilized egg in the uterine
wall.Later though the embryo
receives its nourishment through
the umbilical cord that is attached
to its mother.When the embryo
reaches nine weeks,it is called fetus
until it is born.

59. ENDOMETRIUM

60. UMBILICAL CORD

61. Birth is the process during
which the mother delivers the
fetus.At birth,the muscular walls of
the uterus contract and the amnion
bursts,releasing the amniotic
fluid.The amnion is the membrane
that encloses the embryo and
contains the amniotic fluid,the liquid
envelope taht protects the baby
inside the mother's womb.
BIRTH

62. The fetus is expelled in a
process called parturition,and
after its breathing and
circulation are well
established,its umbilical cord is
cut.The embryonic membranes
are also expelled in a process
called after birth.

63. BIRTH CYCLE

64. ASEXUAL REPRODUCTION
IN ANIMALS

65. Most animals
reproduce sexually to
ensure the continuity of their
species.How ever,some
animals also reproduce
asexually.

66. Types of Asexual Reproduction in
Animals
In asexual reproduction in
animals,off-spring are produced
even in the absence of a mature
germ cell,either the egg or
sperm cell.The types of asexual
reproduction in animals include
budding,fragmentation,fission,
parthenogenesis,and
paedogenesis.

67. BUDDING
In budding,the cells in some areas of an
organism's body organized themselves to form
buds or new individuals.The buds later detach
from the parent organisms.One example is the
hydra,a simple freshwater polyp about 5 mm
long.It consists of about 100 000 cells of roughly a
dozen different types.Dissociated hydra cells
appear first from aggregates or groupings before
regenerating into complete animals.Cells taken
exclusively from the gastric column of the
organisms give rise to complete hydras.
Example of animals that reproduce
through budding are jellyfish,many
echinoderms,corals,hydra,tapeworms, and other
parasitic flatworms.

68. BUDDING
Hydra

69. FRAGMENTATION
Fragmentation occurs when
organisms such as an earthworm or a sea
star split a body parts or parts to several
sections or fragments.The fragmentation
develops and grows into a new individual
or organisms.
If the organisms is split further,the
process of reproduction into a new
organisms with the same properties as the
original organisms is repeated.Hence,the
concept of clonal fragmentation is
adapted.Fragmentation is seen in many
organisms such as molds,starfish, and
worms.

70. FRAGMENTATION
PLANARIAN WORM

71. FISSION
In fission,the organisms
splits either
lenghtwise,crosswise,or
diagonally.This process can
be observed in
bacteria,paramecia,sea
cucumbers,sea stars,sea
anemones,many
echinoderms,flatworms,and
earthworms.

72. FISSION
BINARY FISSION

73. PARTHOGENESIS
Another form of asexual reproduction in
animals is parthenogenesis,or the process when a
new organisms is produced form an organism
without the latter being fertilized.Instead,an egg
cell from the organims is stimulated by sex
hormones that are present in the organism.The
egg cell then develops into an embryo and finally
into a new individual that is identical to the part
organisms.Since the egg cell contains a sert of
diploid chromosome numbers instead of
haploid,the offspring looks the same as the
parent.Some organisms observed to demostrate
parthenogenesis are water fleas,honeybees,sea
urchins,sea anemones,sea stars,sea
cucumbers,paramecia,amoeba, and corals.

74. PARTHOGENESIS
WATER FLEA

75. PAEDOGENESIS
In paedogenesis,young animals that are
usually in larval form reach adulthood without
passing other stages of morphological
development.This means that from the egg,animals
of this kind develop into larvae that are capable of
producing their own kind.Internal parasites of both
humans and animals such as liver
flukes,tapeworms,and ascarides produce larvae that
develop in this manner.Environmental factors may
trigger an organism to produce a larva that will
develop into a new and identical organism to survive
and multiply.
Example of animals that reproduce through
paedogenesis are liver flukes,tapeworms,and
ascarides.

76. PAEDOGENESIS
LIVER FLUKE

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