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GARDENING
WEEK 7
PLANTS NEED ENERGY TOO!
What we would like you to learn:
1. Learn what a plant needs to grow.
2. Learn about the Life Cycle of a plant.
3. Learn the parts of a flower.
4. Learn why many plants depend on bees in order to
reproduce.
STUDENT
Plant Nutrition
When people need energy, we can eat a healthy snack or a well-rounded
meal. What about plants? How do plants get the energy they need to
grow?
To obtain energy, plants undergo a process called photosynthesis. During
photosynthesis, plants use the light energy from the sun to convert carbon
dioxide and water into chemical energy that they store in their leaves as
sugar.
WEEK 7 STUDENT: PLANTS NEED ENERGY TOO!
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What do plants need to undergo photosynthesis?
• Light energy (from the sun)
• Water (absorbed from the soil through the plants’ roots)
• Carbon dioxide (from the air)
• Chlorophyll (stored in the cells of plants, chlorophyll is what gives
plant leaves their green color)
The Life Cycle of a Plant
In the same way that we ask the question: “what came first, the chicken or
the egg?” we can also ask, “what came first, the plant or the seed?” A plant
starts as a seed; this is its first stage of its life. From a seed, the plant
becomes a seedling. From a seedling, the plant grows into a full grown, or
mature plant.
How does a plant produce seeds?
Plants produce seeds through their flowers (the function of a flower is to
produce seeds, and in this way, continue the Life Cycle of a plant). For a
flower to produce a seed, it must be pollinated.
During pollination, pollen grains travel from the stamen of the flower to the
stigma. Once on the stigma, the pollen grains stick and grow a long tube
down the style all the way to the ovary of the flower. In the ovary, the tiny
eggs are fertilized and become seeds. The ovary of the flower becomes the
fruit that contains the seeds. This process is called fertilization.
How do pollen grains travel from the stamen to the stigma?
Pollen grains can reach the stigma in several ways. In some cases, an
insect or a butterfly will feed on the nectar of the flower and brush up
against the stamen. Their bodies transfer the pollen to the carpel and
pollination occurs. In other cases, the wind might cause the pollen to fly
from the stamen to the stigma. Flowers can also become pollinated with the
help of birds, bats, beetles and bees
WEEK 7 STUDENT: PLANTS NEED ENERGY TOO!
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Why Honeybees need Flowers and Flowers need Honeybees
Honeybees are attracted to flowers because they consume the flowers
nectar as a source of energy. Honeybees also collect pollen to bring back
to their hives as food for larvae. When honeybees hover over a flower,
drinking its nectar or collecting pollen, they help the flower to become
pollinated.
Bees are fuzzy. Their bodies are like Velcro. When they fly over a flower,
pollen grains attach to their bodies. When they fly on to the next flower,
these pollen grains may get caught on the flower’s stigma. This is why
honeybees are referred to as pollinators.
FUN Facts of the week:
• Bees carry a static electrical charge, which makes it even easier for
pollen to stick to them!
• If it weren’t for bees, thousands of plants would not get pollinated –
and the Life Cycle of plants would be broken. The fruits that we
cherish and enjoy would not be as easy to find.
Let’s define the following terms:
Photosynthesis: the process by which plants convert light energy into
chemical energy and store it as sugar
Chlorophyll: a biomolecule that gives plants their green pigment and helps
plants to obtain energy from light.
Seedling: a young plant
Pollination: the process by which pollen grains travel from the stamen of
the flower to the stigma
WEEK 7 STUDENT: PLANTS NEED ENERGY TOO!
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Larvae: the early life stage of an insect such as a honeybee. Larvae
develop from eggs. As larvae develop, they spin a cocoon and in this way
grow into pupae that become adult bees.
On your own:
• Observe a cut fruit (or ‘veggie’). Where are the seeds of the fruit?
If you can, bring some of the seeds with you next week.
• In your journal, draw a picture of the fruit and draw where the
fruit’s seeds are located.
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