NATIONAL QUALIFICATIONS CURRICULUM SUPPORT
Biology
Unit 3: Growing Plants
Support Materials
[ACCESS 3;
INTERMEDIATE 1]
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
Contents
Topic 1: Growing plants from seed
Seed structure
Sowing seeds
Instructions for sowing seeds
4
5
6
Topic 2: Vegetative propagation
Plant propagation structures
Methods of artificial propagation
Instructions for taking stem cuttings
7
10
12
Topic 3: Plant production
Conditions for plant growth
Watering systems
Protected cultivation
Plant maintenance
Pests and disease
14
18
20
22
27
Cloze exercises
28
Cloze exercise answers
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 1: GROWING PLANTS FROM SEED
Topic 1: Growing plants from seed
Seed structure
All seeds contain:

an embryo plant (young root and shoot), which grows into the new
plant
 a foodstore for growth (usually made of starch), which the embryo
uses to germinate (grow).
The seed coat protects the embryo and foodstore from damage by
bacteria, fungi and other organisms that live in the soil.
Germination

This is the growth of the embryo into a new seedling (with a new
shoot and root).
 A suitable temperature, water and oxygen are needed for seed
germination.
 Food reserves are used up during germination.
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 1: GROWING PLANTS FROM SEED
Dormancy and germination

Dormant seeds will not germinate until they have the right
conditions for germination.
 Germination is delayed until the spring, when the soil temperature
rises.
Photosynthesis
Once the leaves develop, the plant can make its own food in sunlight by
photosynthesis. The food is used for growth.
Sowing seeds

Intermediate seeds, eg asters, can be sown directly
from the packet or by taking a pinch between thumb and
forefinger and carefully scattering them over the surface
of the compost.

Fine seeds, eg begonia, should be mixed with silver sand. This
allows the seeds to be spaced out more easily and reduces the
competition with each other for water, root-space, minerals
(nutrients) and light.

Pelleted seeds are fine seeds enclosed in a small ball of clay. This
makes small seeds easier to handle and therefore easier to space out.
Pelleted seeds take longer to germinate than non-pelleted seeds and
need more water.

Large seeds, eg sweet peas, can be sown individually in seed trays
or pots.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 1: GROWING PLANTS FROM SEED
Type of seed
Method of sowing
Advantage
Large seeds, eg broad
beans
Individually spread
out
Avoids competition for
space, minerals and food
Fine seeds, eg cress,
begonia
With silver sand
Small seeds difficult to
handle, sand helps seeds
to be sown more evenly
Pelleted, eg. onion
Pelleted
This makes fine seeds
easier to handle
Pellet sometimes
contains fertiliser to
stimulate growth
Chitted seeds (pregerminated), eg sweet
peas
Spread out evenly
Thick seed coat cracked
or slit to allow quicker
germination
Instructions for sowing seeds
1.
Fill a tray with seed compost. Level the compost.
2.
Firm gently.
3.
Scatter the seeds thinly and evenly over the surface of the
compost. Mix seeds with silver sand if they are small or sow
individually if they are large or pelleted seeds.
4.
Cover seeds evenly with a thin layer of sieved compost and firm
gently.
5.
Use a watering can with a fine rose to water the seeds.
6.
Use a pencil to write your name, date, type and variety of seed on
a plant label. Insert the label between the tray and the compost.
7.
Cover the tray or pot with a clear plastic sheet and newspaper , and
place in a propagator.
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 2: VEGETATIVE PROPAGATION
Topic 2: Vegetative propagation
Plant propagation structures
Ways of using plant propagation structures
1.
Bulbs

Bulbs store food. They have buds which produce flowers or daughter
bulbs.
 Since these are produced from one parent, this is a method of
vegetative propagation.
 The food store allows bulbs to withstand winter conditions and to grow
early in spring before seeds germinate.
 Tubers are another example of a food storage organ, eg potato.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 2: VEGETATIVE PROPAGATION
2.
Attached offspring.
Plantlets are miniature plants which are attached to the parent. The
plantlets obtain food from the parent plant until they are established.
An offset is a small plantlet produced as a side shoot at the base of the
parent plant.
A runner is a horizontal stem with a plantlet at the end.
Production of plantlets from runners
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 2: VEGETATIVE PROPAGATION
Production of leaf plantlets
The Mexican hat plant (Bryophyllum) produces large numbers of small
plantlets along the leaf edges. These can be detached from the leaf and
grown in pots of compost.
1.
2.
The piggy-back plant (Tolmiea) also produces plantlets in the
middle of its leaves.
3.
Production of plantlets from offsets.
Some plants, for example mother in law’s tongue (Sansivaria) produce
offsets. Offsets are small plantlets produced as side shoots at the base
of the parent plant. These can be detached from the parent plant and
grown separately.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 2: VEGETATIVE PROPAGATION
Methods of artificial propagation

A new plant can be grown from part of the original plant.
 Methods of reproducing plants without seeds are called vegetative
propagation.
 Artificial propagation means that part of a plant, for example a stem
or leaf, is cut off from its parent and treated so that it grows into a
new plant.
1.
Growing points
Taking stem cuttings

This method is quicker than waiting for the parent plant to produce
seeds and all new plants will be exactly like the parent plant , eg
same colour of flower and leaves.

Nodes are points on a plant’s stem where new growth occurs.

When a plant stem is wounded, for example by cutting below a node,
the stem produces roots. Rooting powder contains a hormone which
speeds up root growth.
Taking cuttings

Cuttings are placed in propagators.

Propagators have electrical cables that supply heat to the cuttings.
This also encourages root growth.

If too much heat is supplied, the plant will wilt as it loses too much
water.

This can be prevented by reducing the leaf surface area by removing
some of the lower leaves or by increasing the humidity by placing
the cutting in a mist propagator or covering it with a polythene bag.
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 2: VEGETATIVE PROPAGATION
Advantages of heat during propagation
1.
2.
Faster growth.
Prevents frost damage.
Disadvantages of heat during propagation
1.
2.
3.
High water loses, leading to wilting.
Higher energy costs.
Faster growth/spread of diseases.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 2: VEGETATIVE PROPAGATION
Instructions for taking stem cuttings
1.
Make sure that the cutting has a growing point. The cutting should
be about 10 cm long.
2.
Cut below a node using a sharp knife and remove the lower leaves
from the cutting.
3.
Dip base of the cutting into rooting powder.
4.
Place the cutting into rooting compost.
5.
Water the cutting to dampen the compost.
6.
Place the cutting in a propagator or cover the pot with a polythene
bag held in place with an elastic band.
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 2: VEGETATIVE PROPAGATION
Layering

Layering is a method of propagating plants which have long flexible
stems.

When the stem is still attached to the parent plant, it is pegged down
into a pot of rooting compost or into the soil if it is an outdoor plant.

Often the stem is wounded by cutting below a node and dusting with
rooting powder to encourage root growth.

When roots develop at the nodes, the stem is cut to separate the new
plant from the parent plant.
Advantages of layering
1.
The new plant is supplied with water, sugar and minerals from the
parent plant.
2.
This means that many plants that are difficult to raise from
cuttings can be propagated by this method.
3.
The plants produced are also larger.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION
Topic 3: Plant production
Conditions for plant growth
Composts

Soil (loam) cannot support healthy root growth in the restricted
volume of a plant pot, therefore composts are used.
 An ideal compost should:
– have an ‘open’ structure which has good aeration (plenty of air)
– have good drainage and be able to hold enough water to avoid
frequent watering
– be reasonably sterile (free from bacteria’s and fungi)
– contain enough minerals for healthy plant growth.
The properties of materials used in composts for growing plants in
containers are shown below.
Materials
Property
Sharp sand or perlite, grit
Improves aeration and drainage
Peat
Improves water-holding capacity
(water retention)
Fertiliser
Increases level of plant nutrients
Loam(soil)
Provides low level of
fertiliser(nutrients)
Needs to be sterilised to kill
bacteria and fungi
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION
There are two basic kinds of composts: loam based and loamless.
The composition of loam-based and loamless compost is shown below.
Loam-based compost
Loamless compost
Major component
Loam (soil)
Peat
Added to improve
root growth


Sharp sand or perlite

Fertilisers
Peat

Sharp sand or perlite
 Fertilisers
Peat substitutes are often used, as using peat is now not seen as
environmentally friendly. Coir dust is an example of a peat substitute
Loamless composts do not require to be sterilised but they do not hold
plant roots as well as loam-based composts. They can become
waterlogged and are difficult to re-wet if allowed to dry out.
Fertilisers
Plants need minerals for healthy growth. The three main minerals that
they need in fairly large amounts are:
Mineral
Importance
1. ‘N’ = nitrogen
For leaf growth
2. ‘P’ = phosphorus (sometimes
called phosphate)
For root growth
3. ‘K’ = potassium (sometimes
called potash)
For growth of fruit and flowers

If there are not enough minerals present in the soil or compost, they
can be supplied by adding fertilisers.

The amount of N, P and K present in fertilisers varies to meet the
needs of different plants.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION

Proportions of N, P and K are shown on the fertiliser packaging in
the order of N, P and K, eg 7-7-14.
K
N
P

Fertilisers can be supplied as liquids or as granules (small pellets).

Granules are easy to apply and break down slowly to release
minerals. They are not blown away by the wind.

Liquid fertilisers are quick acting but nitrogen is ‘leached’ (drains
away quickly from the plant roots).
Watering
Watering – basic rules
1. Do not over water — feel the compost first
to see if it is damp.
2.
Early morning watering is best in summer.
Less water is required in winter, when the
temperature is low.
3.
Do not water if the plants are in direct sunlight. The leaves
may get droplets of water on them. These will magnify the sun’s
rays and burn the leaves.
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION
4.
Some plants, eg African violet, trays of seeds and seedlings,
should be watered from below by placing the container in a tray
of water.
Signs of under-watering
 Leaf edges become brown and dry.
 Leaves may fall off.
Signs of over-watering
 Compost becomes green, slimy and smelly.
 Leaves become soft, yellow and decayed, especially at the bases.
Note: Leaves may droop if the plant is over-watered as well as if
they are under-watered.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION
Watering systems
Automatic watering systems
The main purpose of an automatic watering system
is to allow plants to be watered without anyone
having to do the job, eg by using a watering can.
This type of system saves time and is ideal when people are away on
holiday.
1.
Trickle irrigation

Water reaches each pot through a plastic pipeline that has nozzles in
it to release water.
 The pipeline may be attached to a water tank and water is allowed to
trickle continuously.
 It may be attached to a computer which only allows water to flow for
particular periods of time.
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION
2.

3.





Capillary matting
Capillary matting is a material that sucks-up water and stays moist.
Water-retentive gels
Water-retentive gels are special chemicals that can absorb many
hundreds of times their own weight of water.
They are mixed with compost.
They last for many seasons.
They mean that compost requires less watering.
They are ideal for hanging baskets and plants that are grown in large
containers.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION
Protected cultivation
This includes the use of glass, plastic and floating fleece.
1.
Greenhouses and polythene tunnels
Greenhouses and polythene tunnels protect plants from cold, wind, rain
and frost.
Heating
 There are many ways to heat a greenhouse.
 Electric heating is the most efficient.
 To control the temperature in a greenhouse, the
electricity supply is connected to a thermostat. When the
temperature falls below a fixed temperature, the thermostat switches
the heating on and then switches it off when a fixed upper
temperature is reached.
 The advantage of heating is that it prevents frost damage and
encourages plant growth.
 The disadvantage is that the plant may lose too much water and wilt.
Ventilation
 Ventilation means providing fresh air.
 Stale moist air provides ideal conditions for the spread of disease ,
for example grey mould (mildew).
 Ventilation is also important in controlling temperature and humidity
(how much moisture is in the air).
 To provide optimum conditions for plant growth, automatic
ventilation is essential.
 Automatic systems work without anyone being there to operate
them.
 There are two main automatic systems for controlling ventilation:
cylinders and fans.
Cylinders
1. These are fitted to the windows.
2.
Inside the cylinder, there is a heat-sensitive wax.
3. When the temperature rises, the wax expands, pushing the
cylinder and therefore opening the window.
4. When the temperature falls, the wax contracts and the window
closes.
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION
Fans
1. Greenhouse fans are slow moving so that
they do not cause draughts.
2. They are thermostatically controlled.
3. When the temperature rises, a piece of
equipment called a thermostat, set at a
particular temperature, switches on the
electricity to start the fan.
4. This lowers the temperature and circulates the air in the
greenhouse, also lowering the humidity.
5. The thermostat switches off the fan when the temperature drops to
a certain value.
2.
Floating fleece and cloches

Floating fleece and cloches (tent-like structures made from glass,
plastic or polythene) also protect plants from low temperatures,
wind, rain and pests.
 They raise the temperature of the soil and so make it possible to sow
seeds earlier in the season.
 This increases the percentage germination and allows earlier
harvesting of the crop.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION
Plant maintenance
Methods of maintaining plants
1.





Potting on
A plant needs ‘potting on’ (put into a larger pot) if the roots
completely fill the pot and grow out of the holes in the bottom.
The plant is said to be ‘root-bound’.
Potting on provides the plant with more space for the roots to grow.
It also provides more compost and therefore more minerals.
Potting plants into larger containers should be a gradual process,
increasing the pot size by 25–50 mm each time.
The process of potting on is sometimes called ‘re-potting’.
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION
Instructions for potting on
1.
Carefully support the stem of the plant with
your hand.
2.
Knock the rim of the pot on the edge of a table
to remove the plant.
3.
Select a plant pot that is 25–50 mm larger than the one that the
plant was taken out of.
4.
Place some potting compost in the bottom of the pot.
5.
Place the plant in the centre of the pot.
6.
Check that there is the correct amount of compost.
7.
The plant should sit level with the watering space.
8.
Keep the plant in the centre of the pot.
9.
Place potting compost around the edges and firm down.
10. Repeat this process until the compost is level with the watering
space.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION
2.
Pricking out
Before seedlings become too large and start to compete for light and
root space, they must be transplanted. This process is called ‘pricking
out’. The seedlings are pricked out into seed trays or individually into
pots.
1.
Fill the seed tray with
potting compost and use a
dibber to make holes.
2.
Gently lift out seedlings
with as much compost as
possible around their roots.
3.
Hold seedling by leaves
and drop them into the hole.
4.
Firm compost around
seedling roots and water
gently.
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION
Dead heading
Flowering plants can be encouraged to continue to flower by removing
flower heads that have died.
Types of plants
All types of plants require certain ‘ideal’ conditions if they are to grow
well.
Some need to be kept cool and others need average
warmth.
Bright light is necessary for certain plants but shade
is required for others.
The amount of water and air humidity that certain plants require also
varies.
The types of plants that you need to know for your test can be divided
into five main groups.
1.
Flowering pot plants

These plants are grown for their display of
flowers.
 They can be encouraged to continue to flower by removing flower
heads that have died – a process called ‘dead-heading’.
 Once they have finished flowering, they are thrown away, eg
fuchsia.
2.
Flowering house plants

These plants continue to grow after flowering.
 They may live for a long time, eg African violet.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION
3.

Foliage plants
These plants are grown for the shape and colour of their leaves,
although they may also produce flowers, eg rubber plant.
Note: Many house plants can be grouped as both flowering house plants
and as foliage plants, eg geranium.
4.
Succulent plants

These are plants with fleshy leaves or stems
that can store water.
 Cacti belong to a group of succulents.
5.
Ferns

These are descended from some of the oldest plants of
the earth's history, being found as fossils dating back
nearly 400 million years.
 The leaves, or fronds, of ferns span an amazing range
of shapes and sizes
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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TOPIC 3: PLANT PRODUCTION
Pests and disease
Pests and disease cause damage to plants. They ma y make the plant
look unsightly or lower the yield if it is a crop plant.
1.
Aphids

One of the most common plant pests is the aphid or
greenfly.
 This insect is found mainly at the shoot tips and
flower buds of pot plants, where it sucks the sap from
the plant.

Aphids can be controlled in the following ways:
(a)
(b)
(c)
(d)
spraying with insecticides or pesticides
spraying with soapy water
biological control, ie. introduce ladybirds which
feed on aphids
crushing aphids between finger and thumb.
2.
Fungal diseases






Diseases are mainly caused by fungi (moulds).
A common fungal disease is called botrytis (grey mould).
It can be recognised as it can cover soft-leaved plants, eg begonia
rex and African violet, with a grey fluffy growth.
It can be controlled by spraying with a fungicide and burning
infected parts of the plant.
Moulds like a high level of humidity.
To prevent fungal diseases it is a good idea to cut down on watering
and misting, and to open the windows to improve ventilation.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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CLOZE EXERCISES
Cloze exercises
Growing plants from seed
Use the wordbank to complete each section.
1.
Seed structure
All seeds contain an ___________ (young root and shoot which grow
into the new plant) and a foodstore (usually made of ________ , which
the embryo uses to ___________ (grow).
The ___________________ protects the embryo and foodstore from
damage from ____________ fungi and other organisms that live in the
soil.
______________ is the growth of the embryo into a new ________ and
the use of food reserves (with a new shoot and root).
Wordbank
germinate
starch
seed coat
bacteria
embryo
plant
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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germination
CLOZE EXERCISES
2.
Conditions for germination
When seeds germinate (grow and shoot) they need a
suitable ______________, water and ____________.
Many seeds will not germinate after they have harvested from a plant
even if they have the conditions for germination. These seeds are said
to be dormant.
For example, apple seeds need to go through a long cold
period before germination can happen. This stops
germination during a warm winter spell when a cold
spell would damage the seedling.
The advantage of dormancy is that it delays natural
germination until the spring, when the soil temperature rises and the
temperature, water supply and light are good for growth.
3.
Photosynthesis
Plants make food ____________________.
This occurs in _____________ and the food
made can be used for growth. All ____________
parts of a plant make food but most food is made in the leaves. The
_________ made is stored as starch.
Wordbank
germination
bacteria
embryo plant
germinate
starch
seed coat
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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CLOZE EXERCISES
4.
Sowing seeds
Seeds of intermediate size, eg asters, can be sown directly
from the packet or by taking a pinch between thumb and
forefinger and carefully scattering it over the surface of the
compost.

Fine seeds, eg begonia, should be mixed with
______________________

This allows the seeds to be spaced out more easily and stops the
fight for water, root-space, minerals and ______.

Some fine seeds are in a small ball of _______. Such seeds are said
to be _____________. This makes small seeds easier to handle and
space out.

Pelleted seeds take longer to ____________ than non-pelleted
seeds and need more _________.

Large seeds, eg sweet peas, can be sown in seed trays or ________.

Seeds with thick seed coats are pre-germinated (_____________)
before sowing. The seed coat is ____________ or treated to allow
quicker ______________.
Wordbank
cracked
clay
germination
pelleted
silver sand
light
germinate
pots
water
chitted
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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CLOZE EXERCISES
Vegetative propagation
Bulbs
Bulbs store _______. They have _________ which produce flowers or
daughter bulbs.
Since these are made by one parent, this is a method of vegetative
propagation.
The foodstore allows bulbs to last in ____________ and to grow early
in spring before seeds germinate.
______ are another example of a food storage organ, eg potato.
Wordbank
buds
winter
tubers
food
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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CLOZE EXERCISES
Attached offspring
Some plants produce miniature plants called _________ attached to the
parent.
The plantlets obtain _________ from the parent plant until they start
growing.
In the case of the spider plant and mother of thousands the plantlet
forms at the end of a ______________ (a horizontal stem).
An offset is a small plantlet made as a side shoot at the base of the
parent plant.
Wordbank
runner
plantlets
food
Leaf plantlets
The _________________________________ makes a lot of small
plantlets along the leaf ____________.
These can be taken from the leaf and grown in pots of
compost.
Plantlets from offsets
Some plants produce _________________.
Offsets are small plantlets made as ________________ at the bottom of
the parent plant.
These can be taken from the parent plant and grown separately.
Wordbank
side shoots
32
offsets
Mexican hat plant
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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edges
CLOZE EXERCISES
Artificial propagation
Taking stem cuttings

A new plant can be grown from part of the original plant. Methods
of reproducing plants without ___________ are called
____________ propagation.

________________ propagation is when a part of a plant, eg a
__________ or leaf, is cut off from its parent and ___________ so
that it grows into a new plant.

This is ____________ than waiting for seeds and all new plants
will look ______________ like the parent plant.

Nodes are new ___________ on plant stems.

When a plant stem is wounded, eg. by cutting below a node, the
stem makes new _______________.

__________________ powder contains a hormone which makes
root growth faster.
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exactly
roots
treated
stem
seeds
vegetative
rooting
growth
artificial
quicker
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
33
CLOZE EXERCISES

Cuttings are put in _______________. They are electrical and
give heat to the cuttings. This also encourages
________________.

Too much heat will make the plant _________ as it loses too
much water.

This can be prevented by reducing the leaf __________ area, by
taking away some of the lower leaves and by increasing the
_____________ by putting the cutting in a mist propagator or
covering it with a polythene bag
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wilt
34
surface
humidity
root growth
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
propagators
CLOZE EXERCISES
Instructions for taking stem cuttings
1.
Make sure that the cutting has a __________.
The cutting should be about 10 cm long.
2.
Cut below a _____________________ using a sharp knife.
Take off the ____________________ from the cutting.
3.
Dip the cutting into __________________________.
4.
Water the cutting to dampen the _______________.
5.
Put the cutting in a ________________ or cover it with a
_____________ bag.
Wordbank
lower leaves
rooting powder
node
polythene
propagator
compost
growing point
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
35
CLOZE EXERCISES
Layering

Layering is a way of propagating plants that have
________________ stems, eg ivy, honeysuckle.

When the stem is still part of the parent plant it is
_______________________ into a pot of rooting compost.

The stem can be wounded by cutting below a _______ (point where
leaves are attached) and dusting with rooting powder to help
_______________________at the nodes.

When roots grow, the stem is cut from the parent plant.

_______________ gives the new plant ____________, sugar and
___________ from the parent plant.

Many plants which are hard to grow from cuttings can be
propagated. The plants made are ___________.
Wordbank
36
node
pegged down
root growth
layering
water
long, flexible
larger
minerals
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
CLOZE EXERCISES
Plant production
(i)
Conditions for plant growth
Soil (loam) cannot help root growth alone.
Composts are used to help root growth in a
plant pot.
An ideal compost should:

have an ___________ structure which has good ____________
(plenty of air)

have good _____________

hold enough __________ to stop it having to be watered all the
time

be ______________ (without bacteria and fungi)

have enough ____________ for healthy plant growth.
Two kinds of compost
Loam-based and loamless composts
Main component
Added to help root
growth
Loam-based compost
Loamless compost
Loam (soil)
Peat




Peat
Sharp sand or
perlite, grit
Fertilisers

Sharp sand or
perlite, grit
Fertilisers
There are a few types of loam-based and loamless composts, eg seed
and potting composts.
Potting compost has more minerals as it is used for mature plants that
need more food.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
37
CLOZE EXERCISES
Materials used in composts for growing plants in containers
Materials
Needed for
_________, grit or perlite
Improving drainage
____
Keeping water
__________
Nutrients
____ (soil)
Fertiliser
Peat substitutes
Peat is formed from ______________ plant material.
Substances such as _________ and cocoa shell can be used for
_________________.
Wordbank
minerals
open
sterile
aeration
water
coir
sharp sand
peat
loam
fertiliser
drainage
decayed
Fertilisers
Plants need minerals to grow healthy.
The main minerals needed are:
Mineral
Needed for
1. ‘N’ = ________
For ____ growth
2. ‘P’ = __________
For ____ growth
3. ‘K’ = _________
For growth of ______ and _____
38
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
CLOZE EXERCISES
Plants also need some minerals in small amounts to keep them healthy,
eg iron.

Minerals needed in small amounts are ______________________

If there are not enough minerals in the soil or compost, they can be
added using ______________

The amount of N, P and K present in fertilisers
can vary for different plants.

____________ of N, P and K are shown on the
container in the order N, P and K, eg 7:7:14.

Fertilisers can be ______________ or granules
(small pellets).
_____________ are easy to apply and break down slowly to release
minerals. They are not blown away by the wind.

Liquid fertilisers are quick acting but nitrogen can be ___________
(drains away quickly from the plant roots).
Wordbank
phosphorus
leaf
potassium
nitrogen
flowers
ratios
trace elements
liquids
fertilisers
leached
granules
root
fruit
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
39
CLOZE EXERCISES
Watering
Rules for good watering
1.
Do not ____________. Feel the compost first
to see if it is damp.
2.
Early morning watering is best in
_______________.
Less water is needed in ____________ when the temperature is
low.
3.
Do not water if the plants are in direct _________. The leaves
may get water on them. This will magnify the sun’s rays and burn
the leaves.
4.
Some plants, eg African violet, trays of seeds and seedlings,
should be watered from __________ by putting the container in a
tray of water.
Signs of under-watering

Leaf edges become _____ and ____.

______ may fall off.
Signs of over-watering
40

_______ becomes green, slimy and ______.

______ become soft, yellow and decayed,
especially at the bases.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
CLOZE EXERCISES
Note: Leaves may _________ if the plant is over-watered as well as
under-watered.
Wordbank
droop
summer
below
leaves
winter
sunlight
overwater
brown
dry
compost
smelly
leaves
Automatic watering systems
These watering systems allow plants to be watered
without anyone having to do the job (with a watering
can).
Saves time and good for people away on holiday.
Types
1.

Trickle irrigation
Water gets to each pot through a plastic pipeline which has
___________ in it to let water out.

The pipeline can be attached to a water _________ and water is
allowed to trickle out.

It may be attached to a _______________ which lets water flow at
times.
2.
Capillary matting
______________________ is a material that sucks
up water and stays wet.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
41
CLOZE EXERCISES
Greenhouse tables are covered in polythene and the capillary matting is
put on top.
A piece of matting is put into a container of water.
Water is taken into the _______________, which stays moist.
____________ are put on top.
3.
Water-retentive gels
Water-retentive gels are ___________________ that can
______________ lots of water.
They are mixed with ________________.
They last for many seasons, mean __________________ and are good
for ___________________ and plants grown in large containers.
Wordbank
plant pots
matting
hanging baskets
tank
less watering
special chemicals
absorb
holes
computer
capillary matting
nozzles
compost
42
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
CLOZE EXERCISES
Heating and ventilation
1.
Greenhouses and polythene tunnels
Greenhouses and polythene tunnels protect plants from
cold, wind, rain and frost.
Heating

There are many ways to heat a greenhouse. __________ heating is
the most efficient.

To control the temperature in a greenhouse, the electricity supply is
connected to a __________________.

When the temperature falls ___________ a fixed temperature, the
thermostat switches the ____________ on and then switches it off
when a fixed upper temperature is reached.

The advantage of heating is that it stops _________________ and
encourages plant growth.

The disadvantage is that the plant may lose too much
_____________ and wilt.
Wordbank
water
thermostat
electric
below
frost damage
heating
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
43
CLOZE EXERCISES
Ventilation
Ventilation means providing ___________ air.
Stale ______________ air provides ideal conditions for the spread of
______________ (mildew).
Ventilation also controls temperature and ___________ (how much
moisture is in the air).
______________ ventilation makes good conditions for plant growth.
Wordbank
humidity
moist
automatic
fresh
fungus
Types of automatic ventilation
Automatic systems work without anyone being there.
Fans
Greenhouse fans are ________ moving so that they do not cause
____________.
They are ________________ controlled.
When the temperature rises, the _______________, which is set to a
particular temperature and switches on the electricity to start the fan.
This lowers the temperature and ______ circulates in the greenhouse.
The thermostat switches off the __________ when the temperature drops.
Wordbank
thermostatically
44
draughts
fan
slow
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
thermostat
air
CLOZE EXERCISES
Automatically opening window (cylinders)
These are fitted to the __________ on a
cylinder.
Inside the cylinder there is a heat-sensitive
______.
When the temperature rises, the wax ____________, pushing the
cylinder and opening the window.
When the temperature falls, the wax _____________ and the window
closes.
Wordbank
expands
2.
contracts
wax
window
Floating fleece and cloches
Floating fleece and cloches (tent-like structures made from glass,
plastic or polythene) also protect plants from low temperatures, wind,
rain and pests.
They ____________ the temperature of the soil, making it possible to
sow seeds _________________ in the season.
This increases the percentage ______________ and allows earlier
_________________ of the crop.
Wordbank
germination
harvesting
earlier
raise
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
45
CLOZE EXERCISES
(ii) Methods of maintaining plants
1.
Potting on
Potting on is often called re-potting.
A plant needs ________________ (put into a larger
pot) if the roots fill the pot and grow out of the holes in the bottom.
The plant is said to be __________________.
Potting on gives the plant more ___________ for the roots to grow.
It also gives more compost and so more ________________.
Potting plants into larger pots should be a ____________ process.
Wordbank
minerals
2.
space
potting on
root bound
gradual
Pricking out
Before seedlings become too large and start to compete for light,
____________ and ____________, they must be separated.
This is called ______________ ________.
The __________________ are pricked out into seed trays or pots.
3.
Dead heading
Flowering plants can be helped to continue to flower by removing
_________________________ that have died.
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minerals
46
space
pricking out
seedlings
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
flower heads
CLOZE EXERCISES
Types of plants
All types of plants need ‘ideal’ conditions if they are to grow well.
Some need to be kept cool, some need warmth.
Bright light is needed by certain plants, shade for others.
The water and air humidity needed by certain plants can be different.
The plants can be put into four groups:
1.
Flowering pot plants
2.
Flowering house plants
3.
Foliage plants
4.
Succulent plants.
5.
Ferns
1.
Flowering pot plants
These plants are grown for their flowers.
Flowering will continue if flower heads that have died are
taken off. This is called ______________________.
Once these plants have stopped _____________ they are thrown away,
eg fuchsia.
2.
Flowering house plants
These keep _____________ after flowering and may live for
a long time, eg African violet.
3.
_______________ plants
Grown for the shape and colour of their ________________, and can
also produce flowers, eg rubber plant.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
47
CLOZE EXERCISES
4.
__________________ plants
Plants with ______ leaves and stems which can store
____________.
Cacti are in a group of succulents.
Types of cacti:
Desert cacti: their stems are swollen and their leaves are often reduced
to _____ or hairs, eg. barrel cactus
Forest cacti: grow on ____________ in jungles,
eg. Christmas cactus.
Cacti require _______________ conditions for
good growth.
5.
Ferns
These are descended from some of the oldest plants of the earth's
history, being found as ____________ dating back nearly 400 million
years.
The____________, or fronds, of ferns span an amazing range of
shapes and sizes
Wordbank
succulent
fleshy
dead heading
trees
foliage
spines
water
fossils
sunny
growing
leaves
flowering
48
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
leaves
CLOZE EXERCISES
Pests and disease
Pests and disease can _____________ plants.
The plant may not look ____________ or if it is a crop plant it might
not produce much.
Pests
Aphids
One of the most common plant pests is the aphid or greenfly.
This insect is found mainly at the shoot tips and flower buds of pot
plants where it sucks the ___ from the plant.
Aphids can be controlled by:
(a)
spraying with ______________. or pesticides
(b)
spraying with ____________ water
(c)
_____________ control, ie ladybirds which feed on aphids
(d)
_____________ aphids between finger and thumb.
Disease
Diseases are caused by fungi (moulds).
A common disease is called botrytis (___________________). This can
cover soft-leaved plants with a grey fluffy growth.
Botrytis is controlled by spraying with _______________ and burning
infected parts of the plant.
Moulds like a high level of _____________, so to prevent them it is
good to cut down on _______________and to open windows to help
___________________.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
49
CLOZE EXERCISES
Wordbank
soapy
nice
sap
fungicides
humidity
insecticides
damage
ventilation
biological
crushing
grey mould
watering
50
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
CLOZE EXERCISE ANSWERS
Cloze exercise answers
Growing plants from seed
1.
Seed structure
All seeds contain an embryo (young root and shoot which grow into
the new plant) and a foodstore (usually made of starch, which the
embryo uses to germinate (grow).
The seed coat protects the embryo and foodstore from damage from
bacteria, fungi and other organisms that live in the soil.
Germination is the growth of the embryo into a new plant and the use
of food reserves (with a new shoot and root).
2.
Conditions for germination
When seeds germinate (grow and shoot) they need a suitable
temperature, water and oxygen.
Many seeds will not germinate after they have been harvested from a
plant even if they have the conditions for germination. These seeds are
said to be dormant.
For example, apple seeds need to go through a long cold period before
germination can happen. This stops germination during a warm winter
spell when a cold spell would damage the seedling.
The advantage of dormancy is that it delays natural germination until
the spring, when the soil temperature rises when the temperature, water
supply and light are good for growth.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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CLOZE EXERCISE ANSWERS
3.
Photosynthesis
Plants make food by photosynthesis.
This occurs in sunlight and the food made can be used for growth. All
green parts of a plant make food but most food is made in the leaves.
The food made is stored as starch.
4.
Sowing seeds
Seeds of intermediate size, eg asters, can be sown directly from the
packet or by taking a pinch between thumb and forefinger and carefully
scattering them over the surface of the compost.
 Fine seeds, eg begonia, should be mixed with silver sand.
 This allows the seeds to be spaced out more easily and stops the
fight for water, root-space, minerals and light.
 Some fine seeds are in a small ball of clay. Such seeds are said to be
pelleted. This makes small seeds easier to handle and space out.
 Pelleted seeds take longer to germinate than non-pelleted seeds and
need more water.
 Large seeds, eg sweet peas. can be sown in seed trays or pots.
 Seeds with thick seed coats are pre-germinated (chitted) before
sowing. The seed coat is cracked or treated to allow quicker
germination.
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
CLOZE EXERCISE ANSWERS
Vegetative propagation
Bulbs
Bulbs store food. They have buds that produce flowers or daughter
bulbs.
Since these are made by one parent, this is a method of vegetative
propagation.
The foodstore allows bulbs to last in winter and to grow early in spring
before seeds germinate.
Tubers are another example of a food storage organ, eg potato.
Attached offspring
Some plants produce miniature plants called plantlets attached to the
parent plant.
The plantlets obtain food from the parent plant until they start growing.
In the case of the spider plant and mother of thousands the plantlet
forms at the end of a runner (a horizontal stem).
An offset is a small plantlet made as a side shoot at the base of the
parent plant.
Leaf plantlets
The Mexican hat plant makes a lot of small plantlets along the leaf edges.
These can be taken from the leaf and grown in pots of compost.
Plantlets from offsets
Some plants produce offsets.
Offsets are small plantlets made as side shoots at the bottom of the
parent plant.
These can be taken from the parent plant and grown separately.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
53
CLOZE EXERCISE ANSWERS
Artificial propagation
Taking stem cuttings
 A new plant can be grown from part of the original plant. Methods
of reproducing plants without rooting are called vegetative
propagation.
 Artificial propagation is when part of a plant, eg a stem or leaf, is
cut off from its parent and treated so that it grows into a new plant.
 This is quicker than waiting for seeds and all new plants will look
exactly like the parent plant.
 Nodes are new roots on plant stems.
 When a plant stem is wounded, eg by cutting below a node, the stem
makes new growth.
 Rooting powder has a hormone which makes root growth faster.
 Cuttings are put in propagators. These are electrically heated and
give heat to the cuttings. This also encourages root growth.
 Too much heat will make the plant wilt as it loses too much water.
 This can be prevented by reducing the leaf surface area, by taking
away some of the lower leaves and by increasing the humidity by
putting the cutting in a mist propagator or covering it with a
polythene bag
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
CLOZE EXERCISE ANSWERS
Instructions for taking stem cuttings
1.
Make sure that the cutting has a node.
The cutting should be about 10cm long.
2.
Cut below a growing point using a sharp knife.
Take off the lower leaves from the cutting.
3.
Dip the cutting into rooting powder.
4.
Water the cutting to dampen the compost.
5.
Put the cutting in a propagator or cover it with a polythene bag.
Layering

Layering is a way of propagating plants that have long, flexible
stems, eg ivy, honeysuckle.

When the stem is still part of the parent plant it is pegged down
into a pot of rooting compost.

The stem can be wounded by cutting below a node (point where
leaves are attached) and dusting with rooting powder to help root
growth at the nodes.

When roots grow, the stem is cut from the parent plant.

Layering gives the new plant minerals, sugar and water from the
parent plant.

Many plants which are hard to grow from cuttings can be
propagated. The plants made are larger.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
55
CLOZE EXERCISE ANSWERS
Plant production
(i)
Conditions for plant growth
Soil (loam) cannot help root growth alone.
Composts are used to help root growth in a plant pot.
An ideal compost should:
 have an open structure which has good aeration (plenty of air)
 have good drainage

hold enough water to stop it having to be watered all the time

be sterile (without bacteria and fungi)

have enough minerals for healthy plant growth.
Materials used in composts for growing plants in containers
Materials
Needed for
Sharp sand, grit or perlite
Improving drainage
Peat
Keeping water
Fertiliser
Nutrients
Loam (soil)
Fertiliser
Peat substitutes
Peat is formed from decayed plant material.
Substances such as coir and cocoa shell can be used for drainage.
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
CLOZE EXERCISE ANSWERS
Fertilisers
Plants need minerals to grow healthy.
The main minerals needed are:
Mineral
Needed for
1. ‘N’ = nitrogen
For leaf growth
2. ‘P’ = phosphorous
For root growth
3. ‘K’ = potassium
For growth of fruit and flowers
Plants also need some minerals in small amounts to keep them healthy,
eg iron.
 Minerals needed in small amounts are called trace elements.
 If there are not enough minerals in the soil or compost, they can be
added using fertilisers.
 The amount of N, P and K present in fertilisers can vary for
different plants.
 Ratios of N, P and K are shown on the container in the order N, P
and K , eg 7:7:14.
 Fertilisers can be liquids or granules (small pellets).
Granules are easy to apply and break down slowly to release
minerals. They are not blown away by the wind.
 Liquid fertilisers are quick acting but nitrogen can be leached (drain
away quickly from the plant roots).
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
57
CLOZE EXERCISE ANSWERS
Watering
Rules for good watering
1.
Do not over water. Feel the compost first to see if it is damp.
2.
Early morning watering is best in summer.
Less water is needed in winter, when the temperature is low.
3.
Do not water if the plants are in direct sunlight. The leaves may
get water on them. This will magnify the sun’s rays and burn the
leaves.
4.
Some plants, eg African violet, trays of seeds and seedlings,
should be watered from below by putting the container in a tray of
water.
Signs of under-watering

Leaf edges become brown and dry.

Leaves may fall off.
Signs of over-watering

Compost becomes green, slimy and smelly.

Leaves become soft, yellow and decay, especially
at the bases.
Note: Leaves may droop if the plant is over-watered or under-watered.
58
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
CLOZE EXERCISE ANSWERS
Automatic watering systems
These watering systems allow plants to be watered without anyone
having to do the job (with a watering can).
Saves time and good for people away on holiday.
Types
1.
Trickle irrigation
 Water gets to each pot through a plastic pipeline which has holes in
it to let water out.
 The pipeline can be attached to a water tank and water is allowed to
trickle out.
 It may be attached to a computer which lets water flow at set times.
2.
Capillary matting
Capillary matting is a material that sucks up water and stays wet.
Greenhouse tables are covered in polythene and the capillary matting is
put on top.
A piece of matting is put into a container of water.
Water is taken into the matting, which stays moist.
Plant pots are put on top.
3.
Water-retentive gels
Water-retentive gels are special chemicals which can absorb lots of
water.
They are mixed with compost.
They last for many seasons, need less watering and are good for
hanging baskets and plants grown in large containers.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
59
CLOZE EXERCISE ANSWERS
Heating and ventilation
1.
Greenhouses and polythene tunnels
Greenhouses and polythene tunnels protect plants from cold, wind, rain
and frost.
Heating
 There are many ways to heat a greenhouse. Electric heating is the
most efficient.
 To control the temperature in a greenhouse, the electricity supply is
connected to a thermostat.
 When the temperature falls below a fixed temperature, the
thermostat switches the heating on and then switches it off when a
fixed upper temperature is reached.
 The advantage of heating is that it stops frost damage and
encourages plant growth.
 The disadvantage is that the plant may lose too much water and wilt.
Ventilation
Ventilation means providing fresh air.
Stale moist air provides ideal conditions for the spread of fungus
(mildew).
Ventilation also controls temperature and humidity (how much
moisture is in the air).
Automatic ventilation makes good conditions for plant growth.
60
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
CLOZE EXERCISE ANSWERS
Types of automatic ventilation
Automatic systems work without anyone being there.
Fans
Greenhouse fans are slow moving so that they do not cause draughts.
They are thermostatically controlled.
When the temperature rises, the thermostat, which is set to a particular
temperature, switches on the electricity to start the fan.
This lowers the temperature and air circulates in the greenhouse.
The thermostat switches off the fan when the required temperature is
reached.
Automatically opening windows
These are fitted to the window on a cylinder.
Inside the cylinder there is a heat-sensitive wax.
When the temperature rises, the wax expands, pushing the cylinder and
opening the window.
When the temperature falls, the wax contracts and the window closes.
2.
Floating fleece and cloches
Floating fleece and cloches (tent-like structures made from glass,
plastic or polythene) also protect plants from low temperatures, wind,
rain and pests.
They raise the temperature of the soil, making it possible to sow seeds
earlier in the season.
This increases the percentage germination and allows earlier
harvesting of the crop.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
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CLOZE EXERCISE ANSWERS
(ii) Methods of maintaining plants
1.
Potting on
Potting on is often called re-potting.
A plant needs potting on (put into a larger pot) if the roots fill the pot
and grow out of the holes in the bottom.
The plant is said to be root bound.
Potting on gives the plant more space for the roots to grow.
It also gives more compost and so more minerals.
Potting plants into larger pots should be a gradual process.
2.
Pricking out
Before seedlings become too large and start to compete for light,
minerals and space, they must be separated.
This is called pricking out.
The seedlings are pricked out into seed trays or pots.
3.
Dead heading
Flowering plants can be helped to continue to flower by removing
flower heads that have died.
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
CLOZE EXERCISE ANSWERS
1.
Flowering pot plants
These plants are grown for the flowers.
Flowering will continue if flower heads that have died are taken off .
This is called dead heading.
Once these plants have stopped flowering they are thrown away, eg
fuchsia.
2.
Flowering house plants
These keep growing after flowering and may live for a long time, eg
African violet.
3.
Foliage plants
Grown for the shape and colour of their leaves, and can also produce
flowers eg rubber plant.
4.
Succulent plants
Plants with fleshy leaves and stems which can store water.
Cacti are in a group of succulents.
Types of cacti:
Desert cacti – their stems are swollen and their leaves are often
reduced to spines or hairs, eg barrel cactus
Forest cacti – grow on trees in jungles, eg Christmas cactus.
Cacti require sunny conditions for good growth.
5.
Ferns

These are descended from some of the oldest plants of the
earth's history, being found as fossils dating back nearly 400
million years.
 The leaves, or fronds, of ferns span an amazing range of
shapes and sizes.
UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009
63
CLOZE EXERCISE ANSWERS
Pests and disease
Pests and disease can damage plants.
The plant may not look nice, or if it is a crop plant it might not produce
much.
Pests
Aphids
One of the most common plant pests is the aphid or greenfly.
This insect is found mainly at the shoot tips and flower buds of pot
plants, where it sucks the sap from the plant.
Aphids can be controlled by:
(a)
spraying with insecticides or pesticicides.
(b)
spraying with soapy water
(c)
biological control, ie ladybirds, which feed on aphids
(d)
crushing aphids between finger and thumb.
Disease
Diseases are caused by fungi (moulds).
A common disease is called botrytis (grey mould). This can cover softleaved plants with a grey fluffy growth.
Botrytis is controlled by spraying with fungicide and burning infected
parts of the plant.
Moulds like a high level of humidity, so to prevent them it is good to
cut down on watering and open windows to help ventilation.
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UNIT 3: GROWING PLANTS (ACCESS 3; INT 1, BIOLOGY)
© Learning and Teaching Scotland 2009