Flower Dissection Lab

Biology Resource Manual Pages 26 and 27

Pre-AP Biology Resource Manual Pages 25 and 26

Introduction

Flowers are the reproductive organs of angiosperms, or flowering plants. Flowers vary in size, color, and

arrangement. All flowers, regardless of variety, have the function of increasing the chance of fertilization, thus ensuring seed formation and the production of more plants. Flowers contain both nonreproductive

and reproductive structures. In this investigation, you will examine a flower and identify its nonreproductive and reproductive parts. You will also observe the male

and female sex cells produced by the flower.

Nonreproductive Anatomy of the Flower

Observe the lily pictured on the next page. Refer to the figure below. Identify the receptacle, or the structure to which all other flower parts are attached. Note the sepals in the figure. These are small, leaf like structures above the receptacle. In the lily that you are observing, the sepals are ornamental. That is, they look just like the petals. All of the sepals together are called the calyx. Observe the brightly colored petals inside the calyx. All of the petals together are called the corolla. These structures make up the nonreproductive structures.

Nonreproductive Anatomy of the Flower

As you observe the flower, note the number and color of both the sepals and the petals. Record this information in the appropriate place in the data table in Observations on your data sheet.

Reproductive Anatomy of the Flower

Refer to the figure below and identify the male reproductive structures, or stamens. Each stamen consists of an anther and a filament. Count the number of stamen on the lily and record this information in the data table on your data sheet. Identity the female reproductive structure, or pistil. Each pistil consists of an ovary, a stigma, and a style. Count the number of pistils on your flower and record this information in the data table.

Reproductive Anatomy of the Flower

Sketch the flower in the Reproductive Structure of the Flower section of your data sheet. On the sketch, label the stamen, anther, filament, pistil, ovary, stigma, and style.

Reproductive Anatomy of the Flower

Observe the stamen below, the male reproductive structure. This stamen is magnified using the dissection microscope. Sketch the stamen in the Flower Stamen section of the data sheet. Label the anther and the filament.

Reproductive Anatomy of the Flower

Below is a cross-section of the ovary of the lily. Observe and sketch the inside of the ovary. Draw the number and arrangement of the ovary chambers. The objects inside the chambers are the ovules, or eggs. Label the ovules, ovary walls, and chambers. Count the approximate number of ovules in the ovary and record this information in the data table on your data sheet.

The next slides show sperm containing the male gamete, pollen, and ovules which are the female gamete, eggs.

These structures have been magnified using a microscope.

The Gametes of a Flower

Below is a picture of the ovule, or egg. Sketch the ovule in the section labeled Ovule on your data sheet.

The Gametes of a Flower

The stigma of the flower has a moist, sticky texture. Observe what happens below when pollen brushes against the stigma. Draw the magnified pollen grains in the section labeled Pollen Grains on your data sheet.

Now answer the questions on the next page. Use your book as a resource.