How does water loss from a leaf relate to the... of the cuticle? MiniLab LESSON 1: 30 minutes

Name
Date
MiniLab
Class
LESSON 1: 30 minutes
How does water loss from a leaf relate to the thickness
of the cuticle?
Plants need water for structural support and nutrients. Land plants developed a thickened
layer of waxy material on their leaves, called a cuticle, that prevented water loss. The
thickness of the cuticle varies from one plant type to another.
Procedure
1. Read and complete a lab safety form.
2. In your Science Journal, make a table
like the one shown in your textbook.
3. Choose leaves from four different
plants. Use a balance to determine
the mass, in milligrams, of each leaf.
Record the data in your table.
other leaves. Leave them undisturbed
overnight.
5. Measure the mass of each leaf again
the following day. Record the data.
6. Calculate the difference in mass from
day 1 to day 2. Calculate the percent
difference.
4. Lay each leaf on a small tray, making
sure that none of the leaves touch
Analyze and Conclude
1. Analyze Did you observe any changes in the initial and final masses of the leaves?
2. Compare the thickness of the leaves and determine which type(s) lost the least amount
of water.
3.
Key Concept Consider the structure of the leaf that lost the least amount of water.
Why do you think this adaptation is helpful?
12
Plant Diversity
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Explain.
Name(s)_______________________________
Class _____
Date ____________________
How does water loss from a leaf relate to the thickness of the cuticle?
Lab Data Table
Leaf
Mass (mg)
Day 1
Mass (mg)
Day 2
Difference in Mass
Show all work for calculating % of decrease.
formula: % of decrease = difference in mass / original mass X 100
% of Decrease