Plants are producers

1
Plants at work

2
Plants are producers
Plants get their energy from light Plants make
food by photosynthesis Light energy is trapped
by chlorophyll Most of the food is stored as
starch
3
PhotosynthesisWord equation
sunlight Carbon dioxide water
sugar oxygen chlorophyll Plants make new
biomass during photosynthesis
4
Leaves
Leaves are green because they contain
chlorophyll Leaves have a large surface area to
absorb as much light as possible
5
Testing for starch
Iodine changes from brown to blue-black where
there is starch Method Soften the leaf with
boiling water Remove the green colour with
ethanol Add drops of iodine Look for the colour
change!
6
Variegated leaves

• Some leaves are not green all over
• Some have white and green stripes or patches
• Only the green parts will contain starch

Why?
7
Respiration in plants

• All living things carry out respiration
• Leaves are thin so that gases can get in and out
  easily
• Gases get into and out of leaves through little
  holes called stomata

8
Section through a leaf
Waxy layer
Palisade cells
Spongy cells
Air space
Stomata
Guard cell
Lower surface
9
Plant growth

• Plants need carbon dioxide from the air
• Plants need water
• Plants need light
• Plants need nutrients from the soil including
  nitrogen, phosphorus and potassium
• If the soil does not contain enough nutrients
  then we add fertilisers

10
Fertilisers

• Nitrogen is needed for general growth
• Phosphorus is needed for healthy roots
• Potassium is needed for healthy leaves

11
Plant plumbing

• Water and minerals enter the plant through the
  roots
• Then they go up through little tubes called xylem
  in the plant stem
• Food is transported through tiny tubes in the
  stem called phloem

12
Roots

• Roots keep the plant anchored in the soil
• Roots are covered in lots of tiny hairs
• Root hairs take up water from the soil
• All the root hairs together have a large surface
  area

13
Flowers

• Flowers are a plants reproductive system
• Flowers have male and female reproductive organs
• Male part (stamen) anther and filament
• Female part (carpel) stigma, style, ovary

14
Pollination

• Pollination is the transfer of pollen (male) to
  the stigma (female)
• Pollen grains can be carried by insects
• Pollen grains can be carried by the wind
• When the ovule is fertilised it turns into a seed

15
Making seeds
stigma
Pollen grain

style
ovule
ovule nucleus
ovary
16
Key words

• plant
• seed
• root
• stem
• leaf
• root hair
• starch

chlorophyll photosynthesis carbon
dioxide oxygen phosphorus nitrogen potassium
pollen anther filament stigma style ovule xylem ph
loem