Flower: _____________________ Name: ______________________

Although their reproductive organs differ as do the environments in which they live and reproduce, the basic principles of sexual reproduction are the same in a moss, a flower, a bee and a human. In this investigation, you will learn how the structures of a flower serve the reproductive function.

Click on the Daffodil Image Above to seen an enlarged picture.

MATERIALS:

slide and coverslip	razor blade	dissecting needle (one per table)
microscope (one per pair)	one fresh flower (Daffodil)

PROCEDURE:
1. Examine the outside parts of the flower. The outermost whorl of floral parts may be green or brown and leaflike. These sepals protected the flower bud when it was young. In some flowers the sepals look like an outer whorl of petals. Petals are usually large and coloured and lie inside the sepals. Both sepals and petals are attached to the enlarged end of a branch. These parts of the flower are not directly involved in sexual reproduction. What functions might petals have?

2. Carefully strip away the sepals and petals with the probe or blade to examine the reproductive structures. Around a central stalklike body are 5 to 10 delicate stalks, each ending in a small sac, or anther. These are the male reproductive organs, or stamens. Thousands of pollen grains are produced in the anther. The number of stamens varies according to the type of flower.

How many stamens are present in your flower? ___________

Therefore is your flower a monocot or dicot? ___________

How might pollen be carried from the anther to the female part of the flower?

Draw and label the parts of a stamen.

3. Shake some of the pollen into a drop of water on a clean slide, add a cover slip and examine with a microscope.

Draw a pollen grain.

4. The central stalk surrounded by the stamens is the female reproductive organ, or carpel. It is composed of an enlarged basal (bottom) part, the ovary, above which is an elongated part, the style, ending in a stigma. How do you think the stigma is adapted to trap the pollen grains and to provide a place for them to grow?

Draw and label the parts of the carpel.

5. Use a probe or blade to cut into the ovary lengthwise. Gently open the ovary. Inside are one or more ovules. Each ovule contains an egg.
Approximately how many ovules do you see? _______ (Note: Use dissecting scope to see them clearly.)

How close to the egg can the pollen grain get?

How do the sperm reach the egg?

6. Examine the demonstration ovary under the dissecting microscope at the back of the lab.

7. The union of egg and sperm causes extensive changes in the female reproductive parts. Fertilization of the egg stimulates the growth of the ovary and enclosed ovules.

The ovary develops into the ___________________.

The ovule develops into the ___________________

Daffodil Info: Scientific Name: Narcissus pseudonarcissus Climate: temperate - has long bladed leaves and large yellow flowers - Belongs in the Lily (Liliaceae) Family and is a mono/dicot?

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