chapter 22- cloning and biotechnology Flashcards
what is cloning in plants called
vegetative propagation
Plants can reproduce without fertilisation to produce genetically identical clones.
What is this type of natural plant cloning called?
vegetative propagation
Plants produce clones using what type of tissue
meristematic tissue
why is vegetative propagation good
allows plants to survive adverse conditions
what are the 4 methods of natural cloning in plants/vegetative propagation
runner
tuber
bulbs
rhizome
what is the runner method of natural cloning in plants and eg
A clone is produced using an overground horizontal/lateral stem called a runner
eg strawberry, spider plant
runner withers away> leave new plant independent
what is the tuber method of natural cloning in plants and eg
a clone is produced using a swollen, underground piece of stem called a tuber
eg potato
tip of underground stem is swollen with stored food > form tuber/storage organ > develop buds > shoots
what is the bulb method of natural cloning in plants and eg
A clone is produced from an underground stem, enclosed by layers of leaves, called a bulb
eg daffodil
leaf bases swell with stored food from P, buds form internally > new shoots > new plants
what is the rhizome method of natural cloning in plants and give eg
A clone is produced using an underground horizontal stem (specialised) called a rhizome
sowllen with stored food, buds develop > vertical shoots > independent plants
eg marram grass
Gardners can encourage plants to naturally clone. To do this, part of the stem of a healthy is removed, dipped in growth hormone eg auxin and then placed in soil in a covered pot.
This technique is known a
cutting
precautions when cutting
aseptic techniques (clean scalpel to avoid bacterial infection.
only a few leaves on the cutting to avoid water lost by trans
cover in clear plastic bag to decrease rate of trans
add hormone rooting powder to stimulate meristematic tissue to differentiate into RHCs
soil has water added but it also aerated, o2 needed for R of cells
put in a propagator - warm with sunlight
advantages to producing new plants by cutting (3 things)
It doesn’t require expensive equipment.
It doesn’t require much skill.
It is quicker than growing plants from seed
disadvantages to producing new plants by cutting (3 things)
Some plants are difficult to grow this way.
All of the offspring are susceptible to the same diseases.
A limited number of clones are produced from one plant.
what is grafting
a method of incorporating different variations of species onto the same plant
cut at an angle creating a stock and a scion is added on top
the stock has roots that are hardy
cover wound in wax to stop pathogens
calluse of undifferentiated cells around wound
what is layering
pegging a plant into place to direct its course of growth
dktk
plant tissue either meristematic (capable of CD in adult plants) or permanent (mature cells incapable of CD)
permanent either complex (tissue has more than one cell type) or simple (composed of a single cell type)
complex is either xylem (xylem vessels and tracheids) or phloem (sieve tubes and companion cells)
simple either epidermis (“skin), chlorenchyma
either parenchyma (packaging cells) or collenchyma, or scierenchyma
later 2 make up most of the plant
first step of micropropagation: a small …
small sample of meristem tissue (contains undiff cells, shoot tip and axial bud), called an explant, is taken from a healthy plant.
taken in sterile conditions to avoid contamination from bac and fun, tissue usually vir free
second stage of micropropagation: sample is …
is sterilised to reduce the chances of contamination.
usually by immersing in sterilising agents eg bleach, ethanol or (sodium dichloroisocyanurate which doesnt need washing off so more likely to remain sterile)
3rd step of micropropagation: after sterlisation the sample is … with …
sample is cultured with growth hormones (inc auxins and cytokinins which stim mit but diff for every species) causing a mass of identical cells, called a callus, to grow/cells proliferate
final step of micropropagation: the mass of cells is …
this mass of cells is divided and grown in new cultures containing different hormones and nutrients, to form plantlets, which are potted.
can be planted out to form crop
advantages of micropropagation
rapid production of a large number of plants.
disease free as from meristem tissue.
high yield of eg seedless plants - sterile - banana
known genetic make up
reliable for eg difficult to grow/naturally infertile plants.
control time of year plants are produced eg out of season
more profit to industries
the pollination of plants may not be needed on cloned plants.
It can grow plants which are difficult to grow from seeds.
The plants can be grown at any time of year.
It rapidly produces a large number of clones.
disadvantages of micropropagation
It requires expensive equipment.
All of the clones are susceptible to the same diseases.
It requires a lot of skill.
disadvantage of plant cloning: no ..
variation so decrease frequency in gene pool no new natural selection or mutation so no new beneficial characteristics and because they all have the same genetic info they are susceptible to disease
advantages of plant cloning
lots of new plants in short time frame.
conditions precisly controlled
all plants get characteristics you want eg disease resistant
