Dissect a flower

Basic concepts

Other	Botany	Dissection
Plants	Reproduction

The following is an introduction:

In the spring it seems that nature comes back to life after the winter. Trees are full of leaves, grass grows green and flowers bloom, displaying beautiful colors and sometimes spreading a delicious aroma. But have you ever looked at a flower in more detail? What are the parts of flowers? Are all the flowers the same? In this activity you will discover it by dissecting, or disassembling, a flower piece by piece. How many parts of the plant do you think you can identify?

Background

Plants that produce flowers are known as flowering plants. But is the only purpose of flowers to make plants look beautiful? Not exactly! As beautiful as they may seem to us, flowers are designed to attract pollinators for reproduction. This means that flowers are a crucial part of the process of growing seeds to produce more plants. If you look closely at a flower, you may see that it is made up of many different parts, each with a specific purpose.

Some flowering plants have a stem, which is a kind of long reed that carries water and nutrients and supports the flower. Leaves produce plant food through photosynthesis, a process that helps produce plant food from light, carbon dioxide, and water.

When you look at the flower of a flowering plant, the most obvious parts are probably the petals. They can vary in size and shape, but are usually brightly colored. Their purpose is to attract bees and other insects that help pollinate plants. You may be surprised to learn that some flowers (called 'perfect flowers' in the botanical world) have male and female parts, each playing an important role in pollination.

The male parts, called stamens, look like long stems (known as filaments) with a small round shape at their end (called anthers), which contains the plant's pollen. This bright yellow or orange powder is what insects carry from one plant to another. Pollination occurs when pollen reaches the female part of a new flower, called the pistil. The pistil is usually a long stem located in the center of the flower and is also made up of several parts. Most importantly, it contains the ovary at its bottom, which houses the eggs of female plants, called ova. When pollen falls on a flower's pistil, the eggs or eggs inside the plant's ovaries are fertilized. From that point on, the fertilized eggs become plant seeds and the ovary becomes the fruit.

As you can see, a flower is much more than beautiful to the eye: it is essential for a plant to create more plants. Take a closer look at the different parts of the plants in this activity and see how they differ from one flower to another.

Materials

• Adult helper
• Three fresh flowers of different sizes, such as roses, tulips, lilies, petunias, carnations or irises. You'll need at least the stem with a flower for each of them. Note: Be sure to select 'perfect flowers' that have both male and female parts, such as those just mentioned. If you are allergic to certain plants, be sure to use an alternative.
• A glass or a cup of water
• Six paper plates
• Clamp
• Scissors
• A magnifying glass or magnifying glass (optional)
• At least one additional (intact) sample of each of the flower types you chose to dissect (optional)
• Paper (optional)
• Colored pencils (optional)
• Poster-size paper or cardstock (optional)
• Adhesive tape (optional)
• One or more vegetables or fruits, such as carrots, beets, asparagus, broccoli, cauliflower, tomatoes, apples, peppers, lettuce, peas, corn, or cabbage (optional)

Preparation

1. Label each of the paper plates with a part of the plant ('Stem', 'Petal', 'Leaf', 'Pistile' and 'Stamen').
2. Label an additional paper plate 'Other'.
3. Draw lines on each paper plate to divide it into three sections.
4. Label each section of each plate with the name of one of the three flowers.

Procedure

1. Look carefully at each of the flowering plants. If you have a magnifying glass, you can use it to examine your plants and flowers. What does each flower look like?
2. Choose one of your flowering plants and start dissecting it. Use your hands, scissors or tweezers and carefully disassemble the plant. What parts of the plant can you identify?
3. Once you have removed a part of the plant, try to identify it and place it on the corresponding plate. Place it in the section that is labeled with the correct plant name. Can you find a part of the plant for each dish?
4. If you can't identify a specific part of the plant, place it on the plate labeled 'Other'.
5. When you have finished taking apart the first plant, look at all its different parts. What do the different parts inside a plant look like?
6. Next, repeat the dissection with the two remaining flowering plants. Next, compare the plant parts on each plate. What differences do you notice regarding the same part of the plant of different flowering plants?
7. Look at all the plant parts you placed on the 'Other' plate. What do you think these parts of the plant are? How can you find out?
8. Extra: If you have intact specimens of the types of flowers you dissected, examine them to see how all the different plant parts you identified fit into the complete flower. How do these vary in different types of flowers?
9. Extra: Draw each of your flowering plants on a sheet of paper. Color the plants and label each part you identified.
10. Extra: Make a 'plant parts' poster for each plant: label a sheet of paper with the name of one of your plants. Next, tape the flowering plant to one side of the paper. On the other side, tape each part of the plant to a different section of the paper. Label each part of the plant and decorate your poster.
11. Extra: Did you know that some parts of flowering plants are edible? Look at carrots, beets, asparagus, broccoli, cauliflower, tomatoes, apples, peppers, lettuce, peas, corn, or cabbage. Can you figure out what parts of each plant we usually eat?

Observation and results

Just by looking at your flowering plants, you may have noticed that each plant looks quite different. Obvious differences, for example, are the size or color of a flower. However, when you dissected the plants, you should have been able to identify the same plant parts for each of them. Each of them would have had a stem, with possibly some green leaves on it; colorful flower petals; the female part of the flower (pistil) in the center; and the male parts of the plant (stamen) that produce pollen. If you compare each part of the plant, you may have noticed that they look very different. In general, the petals, for example, tend to look very different from the stems. This is because each part of the plant has a specific function, and its appearance is optimized to fulfill that function.

If you compare the same plant parts of different flowers, you may have noticed that they look somewhat similar. They may not look exactly the same, but it must have caught your attention that they have the same functional characteristics. Although flower petals can differ in size and color, they are usually brightly colored or shaped to attract pollinators, such as bees. The differences between different flowering plants allow us to identify different plant species.

Cleaning

You can put any remaining intact flowering plants in a jar or vase with water. Discard all dissected flower parts in the trash or compost bin. Clean the work area and wash your hands with soap and water.

Adult supervision and safety first

• Carefully follow the experiment instructions.
• It is recommended that a responsible adult help with each experiment.
• While at-home science experiments are great ways to learn about science hands-on, keep in mind that some may require participants to take extra safety precautions and/or not leave everything lost.
• It is advisable that adults handle or help with sharp or potentially harmful materials or objects.
• Adults should review each experiment and determine the appropriate age for student participation in each activity before conducting any experiment.