Transcript Communication

Title: Clones in nature
Homework: complete learning package 11 for Thursday
F215 – module 2
Biotechnologies and gene technologies

Describe the production of natural clones in plants
using the example of vegetative propagation in elm
trees.

Describe the production of artificial clones of plants
from tissue culture.

Discuss the advantages and disadvantages of plant
cloning in agriculture.

Cloning is the production of genetically identical
organisms

In plants cloning can occur naturally by asexual
reproduction.
 All cells are produced by mitosis from cells that were
originally part of the parent plant
 All plants are genetically identical to the parent plant and
each other.

Advantages

Disadvantages
 Quick
 No genetic variety
 All offspring have the
 Does not allow for
genetic information to
enable them to survive
in the environment
natural selection
 Unable to adapt to
environmental
conditions.

Asexual reproduction in plants is known as
vegetative propagation
 Examples
▪ Strawberry plants produce runners
▪ Potatoes form underground tubers
▪ Daffodils produce bulbs
▪ English Elm produces root suckers (basal sprouts)

The English Elm only
reproduces by suckering
 The growth of new trees from
the roots or meristem tissue
in the trunks

As all English Elms are
genetically identical they
are all susceptible to the
fungus, Dutch elm disease
[4]

Complete textbook questions on page 153

Mark your answers using the mark scheme at
the back of the book

Extension: complete the stretch and
challenge question

It is possible to artificially propagate valuable
plants
 Taking cuttings – cut a section of stem between
nodes, then treat with plant hormones to
encourage root growth
 Grafting – a shoot section of a woody stem is
joined to a root stock
 Tissue culture

A node is a region of growth
on a plant.

These small bumps can be
seen where braches and
leaves come off.

Cuttings are taken beneath
the node and the cutting is
dipped in rooting powder,
containing synthetic growth
hormones e.g. auxins to
stimulate root growth

Tissue culture allows for the
production of huge numbers of
genetically identical plants
from a small amount of plant
material.

All stages in tissue culture
must be carried out in sterile
conditions to prevent fungal
infection

A group of cells are removed from the parent plant called the
explant.

Explant is placed on a nutrient growth medium

Cells divide to form a mass of undifferentiated cells called a
callus

Single cells removed from callus and placed on a growth
medium to stimulate shoot growth

The shoots are placed on a growth medium to stimulate root
growth

Growing plants transferred to a greenhouse before planting
outside

Desirable parent plant can be chosen and cloned
 Plants mature at same time

In UK, Annual crops are propagated by seed
 After years of inbreeding all crops are now genetically
uniform
 Even though seeds require sexual reproduction, all seeds
and plants produced are genetically uniform

In perennial plants, the high cost of
vegetative propagation is offset by
 the long periods for which the plants stay in the
ground
 Relatively high value of the product

Examples
 Lavender
 Apple trees

Susceptible to disease

Unable to adapt to climate change

Loss of genetic variation
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