Plants & Human Affairs (BIOL106)  -  Stephen G. Saupe, Ph.D.; Biology Department, College of St. Benedict/St. John's University, Collegeville, MN 56321; ssaupe@csbsju.edu; http://www.employees.csbsju.edu/ssaupe

Environmental Impact on Leaf Anatomy: A Microscopic Analysis

Objectives:  The objectives of this lab exercise are to:

1. provide an opportunity to improve microscope abililties
2. learn leaf adapations to dry (xerophytic), wet (hydrophytic) and moderate moisture conditions (mesophytic)
3. make hypotheses and collect data to support

Introduction:  Leaf  structure is sensitive to environmental conditions.  In this exercise we will explore the response of leaves to dry (xerophytic) and wet (hydrophytic) conditions.  A plant that has evolved in moderate moisture environments is called mesophytic. 

Prelab Assignment (click here)

Protocol: 

1. In class we will go over the care, handling and use of a compound light microscope.
2. Obtain a microscope slide that has three different types of leaves (mesophytic, hydrophytic, xerophytic).  Examine the leaves with the light microscope.
3. Sketch each leaf on a separate sheet of paper.  Label them Figure 1...n and indicate whether it is a hydrophyte, mesophyte or xerophyte leaf. 
4. Measure the thickness of the leaf with an ocular micrometer (we will show you how to use one in lab).
5. On your sketch, indicate the thickness of the leaf.

Post Lab Assignment: 

1. Turn in sketches of each of the three leaves, labeled and measured. 
2. Type up one paragraph summarizing the reasons for your choices of each leaf and whether they match your hypotheses. 

References:

• Basic Microscopy for Plant Pathologists - excellent site from Clemson University
• Microscope help scientists explore hidden worlds  - Nobel Prize Site

Last updated:  01/10/2005 / � Copyright  by SG Saupe / URL:http://www.employees.csbsju.edu/ssaupe/index.html