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Reproduction in lower
and higher plants

Reproduction :
➢ Production of young ones like parents
...

➢ To maintain the continuity of life
...
Asexual reproduction
B
...

● Production of genetically identical progeny, i
...
Clones
...

● Inheritance of genes of parent by progeny
...


Artificial Methods
1) Cutting
Small piece of plant
part selected
...


● Stem cutting
Eg : Rose, Bougainvillea
● Leaf cutting
Eg : Sansev feria
● Root cutting
Eg : Blackberry

2) Grafting
● Joining of two plant
parts stock and scion
Rooted plant - Stock
Joined plant - Scion
● Grow together as one
plant

● Stem grafting
Eg : Apple
● Bud grafting , budding
Eg : Rose

3) Tissue Culture
● Micropropagation :

A small amount of
plant tissue is
carefully and
aseptically grown to
get plantlets
...

Eg : Orchids

Sexual Reproduction
● Involves fusion of two compatible gametes
...

● In higher plants , flowering indicates beginning of
reproductive phase
...

● Variations are useful for survival and evolution of species
...


Flowers, specialized reproductive
structure producing haploid gametes
Accessory whorls :

Essential Whorls :

● Calyx →Sepals
● Corolla → Petals

● Androecium → Stamen
● Gynoecium → Pistil

Parts of flower

Sexual reproduction - Two major events

Meiosis

Production of
gametes (n)
● Male gametes in
anther
● Female gametes
in ovule

Fusion of gametes
(Fertilization)
Diploid zygote
↓
Embryo
↓
New plant (2n)
Sporophyte

Structure of anther - mature anther :
● Usually dithecous (2 lobes) →tetrosporangiate (4
lobes)
● Monothecous (1 lobe) →Bisporongiate (2 pollen
sacs)
● When young it is homogeneous
...

● Heterogeneity appears with formation of
archesporial cell
...
S of anther
● Mature anther has anther wall and micro
sprongium
...

● Microspongium has sporogenous tissue

Anther wall has 4 layer
1
...


2
...


3
...

4
...


T
...

● From archesporial cell 1° patiental cell forms anther wall
Sporogenous cells forms sporogenous tissue
...
Process of formation of microspores by meiosis
from MMC - microspore mother cell
2
...
Pollen wall , double layered - Sporoderm
4
...

Protective layer
...

Presence of thin areas germ pores for emergence of
pollen tube
...

●
●
●
●
●

Intine (inner wall)
●
●
●
●

Thin
Cellulose and pectin
Forms pollen tube
Smooth

Pollen viability

Ability of pollen grain to germinate and develop
male gametophyte
...
- rice and wheat
...


Development of male gametophyte
● It is considerably reduced
...

● Pollen grain (n) is 1st cell of gametophyte
...
First mitotic division - 2 unequal cells →
● Vegetative cell
● Generative cell

Vegetative cell
● Larger, Naked
● Rich in food
● Irregular nucleus

Generative cell
● Smaller, thin
walled
● Dense cytoplasm
● Floats in
cytoplasm of
vegetative cell

2
...
Pollen grains are shed in either two
celled stage or three celled stage
...


● Ovule are present in ovary
...

2
...

4
...

Hilum : point of attachment
Anatropous ovule : curved ovule, where micropyle is near stalk
...

5
...
Micropyle : Narrow opening at the apex of the
ovule
...
Chalaza : Base of ovule
...
Embryo sac (female gametophyte ) : Oval
multicellular structure embedded in the nucleus
...
Process of formation of haploid megaspores from
megaspore mother cell (MMC) which is diploid (2n)
...
Megaspore mother cell → Situated : Nucellus
towards micropylar end
...
By Meiosis : Linear tetrad of 4 megaspores
...
Upper 3 degenerates but lower one is functional
...

2nd mitosis : 2 nuclei formed at each pole
...

➢ One from each pole moves towards centre - polar nuclei
...

● Pollen grains are non- motile and female gametes are
produced at different site
...

● Agents of pollination also act as agent for seed
dispersal
...

Autogamy : Bisexual flower pollinated by its own
pollen shows autogamy
...

Eg : Pea

2) Cross pollination : Outer breeding
● Transfer of pollen grains from the anther of one flower
to the stigma of another flower of different plants of
same species
...

● Need pollinating agent
...

Eg : Food and fibre crops
...


2) Homogamy : Condition when anther and stigma
3)

mature at same time
...

Eg: Viola, commelina

4) Geitonogamy :



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