PLB 105 Fall, 2010
Microscopes and Microtechnique; Introduction to Plant Development
There are three primary goals in the first laboratory session: (1) learn the correct use of the
compound microscope, (2) become adept at preparing plant tissues for microscopic study, and
(3) practicing these techniques while examining tissue and cell changes in developing
The compound microscope is a primary tool in many diverse areas of research,
including the following: medical, plant, animal, microbe, metallurgy, and the
computer industry. Over the years, many college students have been introduced to the
use of the compound microscope, but few students learn how to take full advantage of
this marvelous tool.
Your TA will demonstrate the correct use of the compound microscope. After you
have practiced using the microscope and have mastered its operation, your TA or
proctor will quiz you individually on its proper use. Each student must pass this short
oral quiz before the end of the second laboratory period.
Tissue manipulation and microtechnique must be mastered before you can effectively
study internal plant structure. In this lab you will be introduced to a few different
techniques and get a chance to practice using them. There will be ample opportunity
to use these and additional techniques as the quarter proceeds and your skills improve.
For fun, try to identify tissue types and some of the cell types seen today, but do not
spend much time on this.
You will learn ALL of these during the quarter.
B. Using the Compound Microscope
The TA will point out the following parts of the binocular compound light
Eyepieces, or oculars, (10X). Both eyepieces can be focused.
Revolving nosepiece, or turret, with objective lenses. There are four objective
2.5X, 10X, 40X and 100X (i.e., oil immersion)—these may vary with
different microscopes. The 2.5X objective may be replaced by a different low-
power objective on some of the microscopes. When the microscope is not in use,
the 2.5X objective should be in position. Note: The 100X objective can retracted
by pushing upward and rotating counter clockwise. This lens should always be
retracted when not in use.
Slide holder, mechanical stage, and stage movement controls
Below the stage is an accessory lens that is used with 10X and higher objective
lenses. When using the low-power objective, flip this lens out of the light path.
Condenser, including adjustable condenser diaphragm, focusing knob, and field
diaphragm centering knobs
Field diaphragm adjusting ring