36. Vegetative Propagation

Question 1

Asexual reproduction

Answer 1

Involves one parent.
Doesn’t involve manufacture or union of gametes
Offspring identical to parents.
Happens artificially or naturally

Question 2

Artificial methods

Answer 2

Cutting,
Layering,
Grafting,
Micropropagation (tissue culture)

Question 3

Cutting process

Answer 3

Part of plant cut (usually shoots) and removed from plant
Cuts rooted in well watered compost. 
Sometimes dipped in rooting powders. 
They form new roots, shoots and leaves
eg. bizzie lizzie, geranium, willow

Question 4

Grafting process

Answer 4

Healthy part of one plant removed and attached to a healthy rooted part of a second plant.
Useful qualities from both plants are combined into one.
eg. Apple trees

Question 5

Layering process

Answer 5

A branch of a plant is bent over, pinned and covered in soil, except at tip.
Tip will form the shoot
Covered part forms roots
When roots develop the branch is separated from parent plant.
Good for woody plants
eg. Blackberry, gooseberry

Question 6

Micropropagation process

Answer 6

Cells/small pieces of a plant are removed from plant and placed in a test tube.
Growth regulators and nutrients are added so that growing cells form a group of similar cells that develop into plant tissue.
Used in mass production of house plants and crops like bananas and strawberries

Question 7

Advantages and Disadvantages of Micropropagation

Answer 7

Adv: Provide large number of plants more quickly than cutting.
Dis: Expensive and specialised

Question 8

Natural Methods

Answer 8

1. Modified Stems
2. Modified roots
3. Modified leaves
4. Modified buds

Question 9

Modified stems process and examples

Answer 9

Stems grow runners-horizontal stem running over the soil surface.
Terminal bud of the runner sends up new shoots
eg. Strawberry, creeping buttercup

Question 10

Modified roots process and examples

Answer 10

Root tuber
swollen underground root which remains dormant during winter.
Root becomes modified and is known as a root tuber.
It stores food which the new plant develops from.
New plant grows from base of old stem which has withered away.
eg. Potatoes, carrots

Question 11

Modified leaves process and examples

Answer 11

Plantlets
Some plants produce plantlets at the edge of the leaves.
Plantlets reach a certain size, fall off and grow into new plants.
eg. Lily, Cactus

Question 12

Modified Buds process and examples

Answer 12

Bulbs
A bud becomes modified and is known as a bulb.
This bulb grows into different leaves.
Each of these leaves is swollen with stored food.
eg. onion, daffodil, tulip

Question 13

Compare Sexual and asexual reproduction

Answer 13

Sexual: Cross pollination=variation
Asexual: No variations=advantage in horticulture
S: More resistant to disease
A: All plants the same so more susceptible to disease
S: Dispersal reduces competition
A: Competition and Overcrowding
S: Seeds can remain dormant and survive harsh conditions
A: No seeds= No dormancy
S: Depends on outside agent for dispersal
A: No outside agents needed
S: Slow growth to maturity
A: Rapid growth
S: Wasteful
A: No waste