Pre-Lab: Plant Hormones and Leaves
Problem How does a plant hormone affect leaf loss?
Materials leafy plant, masking tape, permanent marker, scissors, string, toothpick, auxin paste, plastic container or tray
Lab Manual Chapter 24 Lab
Skills Focus Observe, Draw Conclusions, Apply Concepts
Connect to the A plant may flower in response to a change in the hours of daylight, or a plant may stop growing in response to colder temperatures. These responses to changes in the environment are coordinated by plant hormones, which regulate plant development. A hormone may stimulate roots to grow, seeds to germinate, or fruits to ripen. A hormone may inhibit cell division or promote dormancy of seeds or plants. In this lab, you will investigate the effect of a plant hormone on leaf loss.
Explain Do all plant cells respond to every plant hormone? Why or why not?
Explain What is photoperiod? What is dormancy? How are they related?
Review In the fall, what happens to the production of auxin and ethylene in the leaves of flowering plants?
Preview the procedure in the lab manual.
Use Visuals Draw a simple leaf. Label the blade and the petiole.
Control Variables What is the control in this experiment?
Infer How will auxins move from the paste to the base of the petiole?
Visit Chapter 24 online to test yourself on chapter content and to find activities to help you learn.
Untamed Science Video Using time-lapse videography, the Untamed Science crew reveals how plants move in response to various stimuli.
Art in Motion Watch how meiosis and mitosis produce ova and pollen in an angiosperm.
Art Review Review the structures of a flower.
InterActive Art Change the length of day and see how it affects both short- and long-day plants.
Data Analysis Analyze potential fuel energy that comes from different plants and different plant parts.