Biology
Standard III, Objective 1
Title: Plant Structures and Function
Description: Students will examine plant parts macroscopically and microscopically and relate structure to function.
Time Needed: 90 minutes
Materials: celery (with leaves) food coloring, salt, beakers, geranium or other leafy plant, microscope slides, iodine, razors or exacto knives, methyl blue stains, prepared leaf and root tip slides, tree “cookies” (cross sections of tree trunk) flowers (ask for expired ones at a florist) microscopes, Wandering Jew leaf (Barbara has cuttings for you) leaves from a moncot(grass, lily) and dicot (geranimum, tree)
Procedures:
1. Set the lab up in stations so that students work in teams of two. If there are 30 students, you will need 15 stations. You can have two or three of the same station. The students may occasionally have to wait and if you make an extra station or two, that keeps them occupied.
2. Read over the directions with students and pair them up with a partner. Remind them that only one team will be at a station at a time.
3. Allow students time to work and move to each station. Stations should be numbered.
4. Summarize the students’ results at the end of class.
5. Station preparation:
Station One-Celery set in colored water several hours before hand for microscopic examination
Station Two-Tree cookies can be purchased or made in a shop class from whole tree trunks with cross sections sawed cleanly. The diagram below can accompany the cookies.
Station Three-Split celery in two vertically and place one half in salty water and one half in water with food coloring several hours before the lab.
Station three- look at the red, backside of a leaf. The stomata are clearly visible and are green.
Station four-Cut a small piece of the leaf and place it on a slide with cover slip.
Station five-prepared slide
Station six-Have examples of parallel vein and branching veins available.
Station Seven-Prepared Slilde
Station Eight-Flower dissection or observation of an already dissected flower (depending on flower availability)
Student Sheet Name______
Title: Plant Structures and Function
Introduction: Just as human bodies have organ systems that move fluids, provide nutrients, and discharge wastes, plants must also have systems to do the things that allow homeostasis to exist in their bodies. In this activity, you will look at plants both under a microscope and macroscopically, with your eye alone.
Procedures:
1. Working with a partner, visit each station, make observations and record data. Follow the directions carefully and clean up when you leave each station.
2. Answer the questions at the end after the class discussion.
Data:
Station 1-Stem parts
1. Take the razor blade and shave a thin cross section across the bottom of the stem.
2. Place the cross section on the microscope and observe under low power. Draw your results below. Label the xylem, phloem and cambium.
Station 2-A tree cross section
1. Use the diagram to help understand what the layers in the tree trunk mean. Draw your specimen below and label the parts:
2. How many rings does your specimen have? How old was it when it was cut?
Station 3-Salt water and stems
The celery is split in two vertically and one half placed in salt water, the other in red colored water.
1. Draw the celery and describe why it looks the way it does. Use the word osmosis and cells in your description.
Drawing: Describe:
Station 4: Leaves
1. Scan the underside of the leaf and look for stomata. They look like football shaped cells imbedded in other cells. Draw one below:
Station 5-Prepared specimen leaves
1. Look at the slide under the microscope. It is a cross section of a leaf showing the structures inside a leaf.
Use your book and
label as many
parts as you see.
Station 6-Vein patterns
1. Draw and name the two leaves showing the vein patterns.
______
Station 7: Root Tip
1. Look at the tip of the root on the prepared microscope slide.
2. Look at the tip under the microscope and draw what you see. Look for the tip, zone of elongation and root hairs.
Drawing:
Station 8: Flower
1. Draw the flower and label it’s parts. Circle the names of the parts that are female and put a square around the male parts.
Analysis questions:
1. How does the structure of the vascular tissue in plants (xylem and phloem) help it’s function?
2. Why must a tree grow from the outer layers and not the inner layers?
3. What effect does salt water have on the stem?
4. Why?
5. The structures of a leaf are somewhat similar to the structures in skin. Why might they be alike?
6. Veins in a leaf have distinctive patterns. What must the veins do to maintain homeostasis in the leaf?
7. What part of the root grows fastest?
8. Why?
9. What is the function of the petals in a flower?
10. If the anthers in a flower were LOWER than the stigma, what would you assume about how that flower would be fertilized?
Conclusion: