Asexual Reproduction in Plants

Vegetative propagation (definition)

Reproduction without the fusion of gametes

The parent plant and its offspring are …

Genetically identical

What does each new plant form from?

Auxillary bud on the stem of the parent plant

Cloning (definition)

Production of genetically identical organisms by means of asexual reproduction

By what type of cell division are clones produced

Mitosis

Name modified stems

Runner. Stem tubers

Example of a modified stem

Strawberry

Runner (definition)

Branch of the main stem of a plant that grows across the surface of the ground

Where do runners develop?

Auxillary buds at the base of the stem of the parent plant

Where does the daughter shoot spring from on a runner?

Terminal bud

Advantage of runners

One plant can produce many

What is a stem tuber

Underground stem swollen with stored food

Explain a stem tuber

Lateral buds produce new shoots and roots using stored food in the tuber. Parent/old tuber dies away

Name a modified root

Root tuber

Example of a stem tuber

Potato

Example of a root tuber

Dahlia

What is a root tuber?

Form when the fiborous roots of plants become swollen with food reserves

Where is the auxillary bud on a root tuber?

Top of each tuber near the base of the stem

Explain Root tuber

New shoot grows from auxillary bud. Parent plant dies and each root tuber with its bud remains in the ground and each bud will give rise to a new plant

Name a modified leaf

Plantlets

Example of a modified leaf

Brypophyllum

Where do plantlets form

Along margins of leaves

Explain plantlets

When plantlets reach a certain size they fall off. They take root and grow into new plants

Name a modified bud

Bulb

Bulb (definition)

Modified bud

What does a bulb consist of

Small stem bearing a main terminal flower bud. Lateral buds surrounded by fleshy leaves

What do the leaves of a bulb contain?

Stored food

Explain bulbs

Terminal bud produces new leaves and a flower. New bulbs develop from lateral buds

Example of a bulb

Onion

Name four methods of artificial vegetative propagation

Cuttings. Grafting. Layering. Micropropagation

Explain cuttings

Young shoot cut at an angle below a node. Placed in moist compost. Roots will develop

Example of cutting

Geranium

Grafting (Definition)

Joining and uniting of part of one plant with a second plant.

Scion (definition)

Plant to be propagated

Rootstock (definition)

The part onto which the scion is grafted

Example of grafting

Rosebushes

Benefit of grafting

Combines two preferable aspects of two plants into one

Layering (Definition)

The growth of a new plant from the stem still attached to the parent plant

Explain layering

Stem cut at internode. Stemm pegged into soil. New shoot grows at cut

Example of layering

Carnations

Micropropagation (Definition)

Growth of plants from small pieces of tissue under sterile conditions on a specially selected medium

How to encourage growth in micropropogation

Nutrients. PGRs. Temperature regulation

What doees micropropagation result in?

Growth of plantlets

Advantages of vegetative propagation (3)

Allows for desirable features from different plants to be passed down. Faster than natural vegetative propagation. Reliable

Disadvantages of vegetative propagation (3)

Disease can spread quickly because they're genetically the same. Expensive. Grow close to parents increasing competition

Advantages of sexual reproduction (2)

Variety in offspring allowing for evolution and resistance to disease. No competition between parent and offspring.

Disadvantages of sexual reproduction (2)

Rely on external agents.New plants take time to reach maturity