AP Biology

Plant Structure and Function Lab

Chapters 35-36, and parts of 41

Instructions: You will use your textbook as a reference for the lab work you will do in the next few days. You will need to read the assigned pages in their entirety and then refer to them as you do the lab activities.

The emphasis of this work is the relationship between structure and function.

You will be given lab activities on the structure and function of leaves, stems, roots, seeds, flowers and fruit. You may complete the activities in any order you choose. The activities must be completed by Tuesday, Feb. 8 at the end of class. If you need time on your own to complete these activities, you are responsible for making that extra time.

Use colored pencils to create your drawings.

This is a major lab grade. Please be sure the completed lab is neat and organized.

I.  Leaves (pages 748-751)

A.  Leaf Cross Section

1.  Draw and label the leaf cross section on page 750 of your textbook. Write the functions of each structure beside the labels.

2.  Using the Syringa lilac slide, locate the following parts of the leaf. Sketch the slide and label visible structures.

Epidermis Palisade cells

Spongy layer Vascular bundle

Xylem Phloem

Air space Stoma (stomata pl.)

Guard cells Cuticle layer

3.  Write a paragraph discussing how leaf structure contributes to the efficiency of the process of photosynthesis.

4.  Predict adaptations that would be found in leaves located in the following environments.

a.  Desert

b.  Tropical rain forest

c.  Aquatic environment

B.  Stomata and Guard Cells

1.  Break a leek leaf almost in half so that the clear epidermis is the only tissue connecting the leaf halves. Place a small piece of the epidermis on a microscope slide and add one drop of water. Observe the epidermis first under low power, then medium, then high. Draw the stomata and guard cells, as well as the epidermal cells surrounding them. Label all structures.

2.  Write a paragraph discussing the factors that cause the stomata to be open during the day and closed at night. Under what circumstances might the stomata be closed during the day?

II.  Stems (pg. 744-747)

A.  Primary Stems

1.  Sketch and label the following structures on a typical monocot stem, Zea mays (corn), and a dicot stem, Heliathus (sunflower). You should have two sketches for this section.

Cortex Epidermis

Vascular bundle Xylem

Phloem Pith

2.  Which of the tissues above functions in:

a.  Support?

b.  Protection?

c.  Transport?

d.  Food storage?

e.  Growth?

3.  Write a paragraph comparing and contrasting a monocot herbaceous stem, a dicot herbaceous stem, and a woody stem.

4.  Draw and label the tracheid cells of xylem tissue and sieve-tube elements of phloem tissue. Below the drawings, briefly explain the main difference between tracheids/vessel elements and the sieve-tube elements/companion cells. (Use pages 737-738)

5.  Sketch the slide of the sieve cells and label any parts you can identify.

B.  Secondary Stems

1.  Use the cross section of the tree provided to

a.  Sketch and label and secondary tissues

b.  How old is the stem?

c.  What primary tissues produce secondary tissues? Explain how the primary tissues give rise to the secondary tissues.

C.  Woody Twig

1.  Use the directions on the twig anatomy activity to complete the handout provided. You may choose to use the dissecting scope if needed.

III.  Roots (739-743)

A.  Root Cross Section

1.  Use the dicot root slide from Ranunculus to sketch and label the following.

Cortex Endodermis

Xylem Phloem

Epidermis Stele

Pericycle Pith

2.  Which tissues function in:

  1. Protection?
  2. Absorption?
  3. Transport?
  4. Food storage?

3.  Describe the role of the endodermis in the absorption of water and minerals. (See page 741)

4.  Obtain the transverse section of the carrot and complete the directions on the carrot lab.

5.  Use the monocot root slide to sketch a monocot root. What are the differences between a monocot root and a dicot root?

B.  Longitudinal Root Cross-Section

1.  Using the Alium root tip to sketch and label the following:

Root hair Zone of maturation

Zone of Elongation Apical meristem

Root cap

2.  Describe the purpose/function of:

  1. Root hairs
  2. Apical meristem
  3. Root cap

3.  Why are root hairs found only in the zone of maturation and above.

IV.  Flower (840-848)

A.  Structure:

1.  Using the flower diagram on page 840, sketch and label the following parts of a flower.

Sepal Pistil/Carpel

Petal Stigma

Stamen Style

Anther Ovary

Filament Ovule

Receptacle

2.  Remove the floral parts and identify the reproductive structures in the live flower provided.

3.  Place the stamen under the dissecting microscope and observe the anther.

4.  Remove some pollen and observe under the light microscope (dry mount with a coverslip). Sketch the pollen grains. You may use the Lilium pollen/anther slide for comparison.

5.  Using the scalpel, cut the carpel longitudinally. View with the dissecting microscope and sketch. Label the ovary and the ovules. You may use the Lilium ovary slide for comparison.

6.  Differentiate between the following:

a.  Complete and incomplete flowers

b.  Perfect and imperfect flowers

c.  Monoecious and diecious flowers

B.  Fertilization:

1.  Write a paragraph describing double fertilization in flowering plants. Explain why double fertilization is important and efficient.

V.  Seeds (We’ll do as a class)

VI.  Fruit (pg. 760-762)

1.  What does a fruit develop from?

2.  Describe each of the following types of fruit and give an example of each:

a.  Simple fruit

b.  Aggregate fruit

c.  Multiple fruit

3.  Distinguish between a dehiscent and indehiscent dry fruit. Give an example of each.

4.  What purpose do fruits serve in the success of flowering plants.