Pumpkins have two kinds of flowers. One flower makes pollen and is called a male flower. Most flowers on a pumpkin plant are male flowers. These have long thin stems called petioles. On the day you want to do this Investigation, go out early in the morning and pick a male flower. It may have insects in it. Use a long grass stem to push them out. Don’t knock the flower about, especially upside down or all the pollen will fall out! Put the flower into a glass of water until you are ready to look it over. It will wilt in just a few hours so let’s start early and find out about a male flower.
Question: What parts are in a male pumpkin flower?
Male Pumpkin Flower
Slide and coverslip
Step 1: Open your Science Journal, write “Investigation 15” and the date.
Step 2: Examine the outside of the male flower. Measure how tall it is. Compare it to the diagram of a flower and label your drawing with the parts.
Step 3: Smell the inside of the flower.
Step 4: Carefully tear or cut off the petals of the flower and lay them out on the table.
Step 5: Examine the petals. Compare the inside and outside surfaces – look, color, feel.
Step 6: Examine the stamen. Measure the stamen. Touch the stamen. Draw and describe what you observe.
Step 7: Put a drop of water on a slide. Put some of the pollen from the stamen on the water. Put on the coverslip.
Step 8: Examine the pollen with the microscope.
Step 9: Carefully slice the stamen in half lengthwise and examine the inside.
Explain why you think a pumpkin flower has only one or has many petals joined (fused) together.
If a pumpkin flower has fused petals, how many petals are there? How can you tell?
What advantages would fused petals instead of separate ones give a pumpkin flower? (You might want to look at some flowers on your pumpkin plant in the early morning to get some ideas.)
Each seed in a pumpkin flower needs one grain of pollen to become a seed. Why are there so many more male flowers making pollen than female flowers (These have tiny pumpkins under them.)?
Why do you think the flower makes so much pollen since only one grain or piece is needed for each seed?
Many flowers have lots of little stamens. A pumpkin flower seems to have only one. Does the pumpkin flower have fused stamens? Explain why you think so.
Different kinds of plants have pollen grains (separate pieces of pollen) with different shapes. Archeologists use fossil pollen to identify the kinds of plants that grew in an area long ago. What special things about a pumpkin pollen grain do you see?