plant cloning

cloning

the production of genetically identical cells or organisms

type of reproduction in cloning

asexual reproduction

type of cell division used in cloning and why?

mitosis

→produces genetically identical cells

→clone cells remain diploid

types of cloning

-natural

-artificial

natural cloning in plants

produce natural clones by vegetative propagation

vegetative propagation (2)

-type of asexual reproduction

-produce clones from non-reproductive tissues e.g. roots, stems, leaves

examples of vegetative propagation

-runners [/stolons] [horizontal stems grow on the surface] [e.g. strawberries]
-bulbs [e.g. onion]
-tubers [underground stems] [e.g. potato]
-rhizomes [horizontal underground stems]

-sucker [shoot grow from the roots or lower stem of a parent plant]

[tubers and bulbs food stores which help plants survive]

Difference between runners and rhizomes

-runners are on the surface of the ground whereas rhizomes are underground

simple cloning in plants

take plant cuttings

how to clone plants by taking a cutting

-cut shoot from healthy plant

-cut stem at a slant between nodes

-remove leaves to reduce transpiration

-dip in rooting powder

-place in soil and add water

artificial cloning in plants

tissue cloning/ micropropagation

micropropagation

producing many genetically identical plants through tissue culture

tissue culture process

-cut plant materials into small pieces (explants) → taken from the stem or root tips as they have meristem cells

-sterilise explant to kill microorganisms

-place on agar containing glucose, amino acids and plant growth hormones

-cells divide to produce a callus (mass of undifferentiated cells)

-there’s high auxin and cytokinin concentration for for callus formation

-sub-divide the callus into smaller pieces

-transfer pieces to fresh medium with different hormone concentrations to encourage shoot and root formation

-plantlets develop and are transferred to soil

-they develop into plants that are genetically identical to the parent plant

uses of tissue culture

-produce clones of endangered plant species→ helps preserve biodiversity

-produce clones of genetically modified plants

-produce clones of plants that are resistant to diseases

name structure X and outline how a gardener could produce many cloned plants from structure X.

name structure Y

bulb

→ cut bulb and plant it to grow

runner

pros and cons of artificial cloning

PROS

-can be done at any season

-produce uniform crops→ desirable genetic characteristics [name it if mentioned in q] are passed on to clones (e.g. same yield, same size)

-produce clones of endangered plant species→ helps preserve biodiversity

-quicker than growing from seed

-less space required for tissue culture

CONS

-low genetic diversity→ plants are more susceptible to diseases and environmental change

-undesirable genetic characteristics can be passed to clones

-risk of contamination by microorganisms during tissue culture