Tag Archives: pistil

OS16 Female Pumpkin Flowers

Investigation 15 looked at the male pumpkin flower. It only produces pollen, no pumpkins. The female pumpkin flower can grow into a pumpkin. Remember to pick your flower early in the morning and put the stem into a cup of water. Let’s look at a female flower.

Question: What parts are in a female flower?

female pumpkin flower

Materials:

Female Pumpkin Flower

Metric ruler

Knife

Magnifying glass

Procedure:

Step 1: Open your Science Journal, write “Investigation 16” and the date.

Step 2: Examine the outside of the female flower. Measure how tall it is. Compare it to the diagram of a flower on page 101 and label your drawing with the parts you see.

Step 3: Smell the inside of the flower.

Step 4: Carefully cut or tear the petals off the flower.

outside pumpkin petal

Three green veins go up the outside of each of the five lobes of a pumpkin flower. Only the tops are orange.

Step 5: Examine the petals. Compare the inside and outside surfaces [look, color, feel etc.].

Step 6: Examine the inside of the female flower. Measure the pistil. Touch the pistil. You can safely taste the liquid on the pistil. Draw and describe what you observe.

pumpkin flower pistil

Isolated from its flower a pumpkin flower pistil is a bumpy wet mound.

Step 7: Examine how the pistil joins the ovary [tiny pumpkin].

Step 8: Carefully slice the pistil and ovary in half lengthwise. Examine what you see in the two halves. Draw what you see.

pumpkin flower ovary longitudinal cut

Each line of ovules extends down the length of the pumpkin ovary. Each ovule has the potential to become a pumpkin seed.

Step 9: There should be a line of ovules or tiny seeds showing in the ovary. If there isn’t, cut a thin slice off the ovary to find a line of ovules.

Step 10: After you examine the line of ovules, cut across that half of the ovary and look for where lines of ovules are.

Observations:

Describe a female pumpkin flower

Label the parts on your drawing

Describe the outside of the petals

 

inside pumpkin flower petal

Inside a female pumpkin flower petal each main vein stands out in green against a pale yellow background. Only the tops of the petals are orange.

Describe the inside of the petals

 

split pumpkin pistil

Split in half its easy to see the single pistil isn’t single at all but several pistils clumped together.

Describe the pistil.

Describe the tiny pumpkin.

Describe how the inside of the pistil and ovary join

Describe the ovules

Number of ovules in one row:

Number of rows of ovules in half the ovary:

Number of ovules in half the ovary:

Number of ovules in the ovary:

Analysis:

Multiply the number of ovules in a row by the number of rows in half an ovary.

Multiply the number of ovules in half an ovary by two for the number of ovules in an ovary.

Conclusions:

If all the ovules in an ovary become seeds, how many seeds will there be in the pumpkin?

 

pumpkin flower ovary cross section

Each line of ovules is inside a spiral arm. Each half of an ovary has three lines of ovules.

If every ovule must join with one grain of pollen to become a seed, how many grains of pollen must be carried by insects to the pistil?

Why do you think the pistil is wet and sticky?

 

enlarged pumpkin pistil

Magnified a pumpkin pistil has many bumps making its surface look grainy.

What do you think makes the pistil wet and sticky?