hloem on same radius, chloroplasts present
ide ring, fascicular cambium present, well defined cortex and pith
of xylem and phloem, no fascicular cambium, intact epidermis and primary cortex
ular bundles, wide pith, collenchyma in cortex
through the stem of
r than this
ow the cells are joined
g of a T.S. through the stem of
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 seedlings.
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 microscope:
Eyepieces, or oculars, (10X). Both eyepieces can be focused.
Revolving nosepiece, or turret, with objective lenses. There are four objective lenses:
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.