Reproduction
The characteristic of living organisms which produce a
new generation is known as reproduction.
Reproduction
Asexual Reproduction Sexual Reproduction
• Only one parent is involved. • Two organisms are involved.
• Offspring are similar to the • Offspring have mixed
parent. features
• Gametes are not involved • Gametes are involved
• Mitosis occurs • Meiosis occurs
• New species are not • New species may be
produced produced
Reproduction of Plants
Reproduction of plants
Asexual Reproduction Sexual Reproduction
(vegetative propagation)
• Flowers are pollinated
• Flowers become fruits
Natural Artificial • Seed are dispersed
• roots • stem cutting
• leaves • layering
• suckers • grafting
• runners • tissue culture
• bulbils
• underground stems
Asexual Reproduction (vegetative propagation)
• Advantages of vegetative propagation
Can get new plants when seeds are not producing new plants.
Can get identical plants
Can get plants with high resistance
Can propagate rare plants easily
• Disadvantages of vegetative propagation
New varieties are not produced
Natural Asexual Reproduction
• By roots
ex : Curry leaves, Bread fruit
• By runners
ex: Gotukola/Vallarai, Sweet potatoes,
strawberry
• By Leaves
ex:Begonia, Akkapana/Sathaikkaraichchan,
• By Suckers
ex:Paddy, Banana, Pine apple
• By bulbils
ex:Pine apple, Jute
• By Underground stems
Rhizome
(Ex: Ginger, turmeric)
Corm
(Ex: Habarala)
Bulb
(Ex: Onions, Leeks)
Stem tuber
(Ex: Potato)
Artifical Asexual Reproduction
• Stem cutting / rooting
(Ex: Rose, Shoe flowers, Bougainvillea)
• Layering
Layering
Ground Layering Aerial Layering
When the branches are closer When the branches are not
to ground closer to ground
Ex: Jasmin, Lemon Ex: Lemon, Pomegranate
• Grafting
A bud or a twig of a plant is attached to another plant of the same or
related species.
Ex: pears, mango, lime, lemon
Grafting
Twig grafting Bud grafting
• Tissue Culture
An advance technology where a large number of plants will
be produced from a small vegetative tissue of any plant.
This will be done under controlled conditions in an artificial
medium.
Offspring obtained are known as ‘clones’.
Artificial medium Controlled conditions
Vegetative part • Vitamins • Temperature Cloned
of a plant • Minerals
•
• Light offspring
(bud, root tips) Growth substances
• Agar
Questions
1. Name few types of twig grafting methods
2. Name few types of bud grafting methods
3. Name 3 advantages of grafting
4. Name 3 disadvantages of grafting
5. Name 5 advantages of tissue culture
6. Name a main disadvantage of tissue culture.
Sexual Reproduction
FLOWERS
BISEXUAL UNISEXUAL
FLOWERS FLOWERS
Flowers contain of both male and Flowers contain one of male or
female parts female parts
Ex: Shoe flower, Chili
Monoecious Dioecious
Plants Plants
Bear male and female Bear male and female
flowers in the same plant flowers in separate plants
Ex: Pumpkin, Corn,
Ex: Papaw, Vallisneria
Coconut, Bitter gourd
BISEXUAL FLOWERS
Monoecious Plants
Dioecious Plants
Pollination
Pollination is the process of depositing pollen on the
stigma of a flower.
1. Self pollination
Pollen of a flower is deposited in the stigma of
the same flower
2. Cross pollination
Pollen of a flower is deposited in the stigma of
another flower.
(same plant or different plant)
Some plants show adaptations to avoid self pollination
and promote cross pollination.
• Having unisexual flowers
• Self sterility
• Hercogamy (stigma and stamen are located apart)
• Extrorse stamens (stamen bent away)
• Dichogamy (not matured at the same time)
• Having unisexual flowers
• Hercogamy (stigma and stamen are located apart)
• Extrorse stamens (stamen bent away)
• Dichogamy
Fertilization
• The fusion of male gametes with female
gametes is fertilization.
• This happens after pollination.
• After fertilization;
✓ Ovary becomes the fruit
✓ Ovules becomes seeds
Homework
1. Name the three pollination agents and give examples.
2. Name the seed dispersal methods and give examples.
3. Name the pollination method of below plants,
a. having colourful flowers
b. very light pollon grains
c. producing a large number of pollons
e. aquatic plants
4. Name the seed dispersal method of below plants,
a. seeds having hooks
b. seeds are light and has hair like structures
c. seed is coated with fleshy fruit
d. fruits have air cavities
