Germination
State the conditions that affect germination
Germination:
The process by which a plant grows from a seed
Conditions:
1. Temperature
2. Oxygen
3. water
Why are the above
conditions needed for
germination?
Flower Structure Pollination Fruit Development Seed Dispersal Germination Test
The seed contains the embryo plant and
cotyledons
Testa Draw and Label the diagram
of the seed (205)
1. Role of the testa
Plumule 2. What parts make up
(_____ shoot)
the embryo
3. Role of the
micropyle
4. Role of the
Radicle cotyledon
(_____root)
Micropyle Cotyledon
1. Water enters the
Testa seed through the
micropyle and
activates enzymes
Plumule and makes the
tissues swell and
break the testa
allowing O2 to enter.
2. Amylase +
Radicle
proteases
3. Respiration give the
plant energy for
growth
Micropyle Cotyledon
Flower Structure Pollination Fruit Development Seed Dispersal Germination Test
Whilst germinating the plant uses food stores in the
cotyledon to provide energy for growth
light The seedling can now
photosynthesise and
make its own food
germination
Plant growth and development
soil
EOC Q 3
Conditions required for germination
Summarise the findings of the experiment shown below:
Click to
listen to an Pyrogallol (absorbs oxygen)
No light
explanation
Oxygen Oxygen Oxygen Oxygen
present present present present
No
oxygen
moist dry moist moist moist
4oC Warm Warm Warm Warm
A B C D E
Flower Structure Pollination Fruit Development Seed Dispersal Germination Test
Changes in dry mass of the germinating seed:
Click to
Seed loses weight as it uses listen to an
up starch stores in the explanation
cotyledons as the seedling
cannot photosynthesise yet
Dry mass/g
Weight increases as
the seedling can
photosynthesise and
Dry mass is the plant grows
mass of solid
matter with all
water removed
Days
Flower Structure Pollination Fruit Development Seed Dispersal Germination Test
3bcompetition with established trees and
1.Maximizes Survival Chances: By other vegetation. These gaps often
germinating only in well-lit areas, the provide access to more sunlight,
seedlings are more likely to survive. nutrients, and space, which allows the
Light is essential for photosynthesis, seedlings to grow more quickly and
which fuels growth. Germinating in poor establish dominance.
light conditions would likely lead to 4.Strategic Growth: Trees that rely on
weak or stunted seedlings that may not light for germination take advantage of
survive. the natural cycles of disturbance in the
2.Efficient Resource Use: Trees investrainforest (like falling trees or
significant energy in producing seeds, landslides) that create light gaps. These
so it is advantageous for seeds to gaps provide the perfect opportunity for
germinate in conditions where they are young trees to establish themselves in
more likely to thrive. By waiting for an environment with less competition,
sufficient light, the tree ensures its ensuring the tree species can spread
offspring have the best chance of effectively.
success, avoiding wasted energy on In short, this strategy increases the
seeds that germinate in unsuitable tree’s reproductive success and
conditions. ensures its long-term survival in the
3.Reduced Competition: Germinating competitive rainforest environment.
in well-lit gaps in the canopy reduces
