Introduction - 1
Introduction to the Botany Lab
A. Lab Organization
The botany lab has a basic organization that makes materials, demonstration material, and reference
pictures and charts easy to locate.
1. Typical Student Station:
compound microscope (left cabinet)
full set of prepared slides (black slide box)
stereo dissection microscope (right cabinet, but at only about half the stations)
2. Each End of Each Student Bench
glass slides
cover slips
distilled water bottle
Gram’s iodine stain bottle
neutral red stain bottle
dissection needles
forceps
hand lens
lens tissue packet
plant materials, as needed
3. Perimeter Benches (in order of lab coverage)
plant and other materials
work stations
demonstrations, charts and illustrations
4. Bulletin boards and hanging charts
additional support material
Warning: Most labs are accompanied by a wealth of support material. Use:

your instructor’s advice

the lab manual

your own interests
to pick and choose the most important components. Your success in the course can be very
much influenced by your ability to use the labs with discrimination.
B. Housekeeping
You share your work station with students from other sections, so please keep it in good condition.
Please restore every place you work to a condition as good as, or better than, you found it. Let the
instructor know if there are problems passed on to you from previous users.
Each station is equipped with a box containing the entire semester's set of prepared slides. This is a great
convenience, but requires a little collective maintenance. Please do your best to keep slides clean, in
order, and in place according to the key on the box lid. Try to avoid mixing slides between sets. Make the
instructor aware of missing or damaged slides, because you are liable for slide breakage (see Biology
Department policy statement below).
Slide use guidelines:
(1) Since a complete box of slides represents a large investment, handle it carefully and keep it away
from edges or corners of the lab bench where it could be inadvertently knocked off.
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(2) Use one slide at a time unless an exercise specifically requires more than one. Replace each slide
in the box in the right place when you are done with it and before you take another. Never set slides
on papers, books or table top. That often leads to accidental breakage.
(3) Pay attention to how you put a slide into the mechanical stage. Keep stage scrupulously clean and
dry. Carefully clean all traces of immersion oil from sides and stage.
(4) When you finish with slides that you have made yourself, dispose of the plant material in an
appropriate way (bacterial slides get dipped in disinfectant). Then wash the slides at the sink, dry them,
and return them to the slide boxes. Throw away scratched cover slips, but please clean and reuse ones
that are still in good condition.
C. Biology Department Equipment Policy
(1) Students will not be charged for class use of expendable materials such as chemicals, seeds, and
cultures.
(2) Breakage of equipment (such as glassware or slides) during class use will not result in a charge if:
(a)
and
the student returns the broken or defective equipment to the instructor or the stockroom,
(b)
the student has followed proper laboratory techniques. (See limitation in part 3.)
(3) Breakage will result in a charge if:
(a)
the broken or defective equipment is not returned to the instructor or stockroom, and/or:
(b)
the individual student's breakage total exceeds that expected despite using proper
technique.
(i) “Normal” is considered to be breakage of not more than three items per semester or not
exceeding a total value of $10.
(ii) Microscope slides fall into the “normal breakage” category for the first four weeks of the
semester only. After that, we assume that any student will be able to use proper microscope
technique at all times and simply not break slides. Any prepared slide damage that occurs
after week four will result in a charge equal to the cost of replacing the slide.
D. Botany Open Study Laboratories
Normally, both botany laboratories are open two evenings per week for continued study or review. The
laboratories contain the same materials that were present during the scheduled labs that day, so there is
typically a selection of material from two different course units. Since the study labs are shared by
students from all sections, there is no expectation or guarantee that students will work at their assigned
lab stations.
For the sake of all users, students attending the study labs should observe the following guidelines:
(1) Use the laboratories for study and review only and go elsewhere for socialization or interaction
that would be disruptive to academic users.
(2) Follow department breakage guidelines (see above).
(3) Leave materials and equipment where they belong. This includes:
(a)
Removing no laboratory materials from either laboratory, even temporarily;
(b)
exchanging no materials between laboratories. In study labs, students may work at any
vacant lab station.
(4) Follow instructions of the proctor about appropriate laboratory use.
While the proctors can be a great source of help and information, they should not be expected to have all
the answers. In general, you should try to do as much during scheduled labs as possible, and use the
study labs primarily for review and enrichment.
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E. Microscopes:
For more than half the course, your compound microscope will be the most important, most used piece of
equipment. The compound microscopes are binocular, for viewing ease, but the image is transmitted
through only a single objective lens, so stereo vision is not possible. The lab is also equipped with
stereoscopic, broad-field microscopes. These allow true 3-dimensional viewing as well as direct
manipulation of viewed material, but they don't provide enough magnification to work at the cellular level.
Such microscopes are also called dissecting microscopes.
2. Microscope Use and Care Guidelines:
(1) Form the habit of using both hands to carry the microscopes, one supporting the base, and one
stabilizing the upper part. Our compound microscopes are formed from one integral unit, but many
excellent microscopes have lens column and base held together only by the rack and pinion used in
focusing, as do our broadfield microscopes. Hold the microscopes upright so that the eyepieces do not
fall out. It is possible to lock eyepieces into a microscope tube, but then it is inconvenient to switch
eyepieces.
(2) Keep lenses as clean as possible! A large proportion of alleged microscope malfunctions turn out
to be dirty objective lenses. Note that some of the objective lenses are somewhat recessed, and
therefore a little hard to clean. Clean lenses only with lens paper!
(3) Keep slides and cover slips clean. Starting with a dirty slide or cover slip is likely to be a waste of
your time. Try to recycle (wash and dry) slides and cover slips whenever possible, but discard cover
slips that are dirty or scratched. Be sure to ask the instructor for cover slips or slides if either are
missing.
(4) Move the distance between the eyepieces (interpupular distance) until you comfortably see a single
image. If you wear glasses, experiment with keeping them on or leaving them off. If your vision needs
lots of correction, it will probably work better to get used to wearing your glasses while using the
microscope. Our microscopes are highly adjustable, but if you change the focus of an eyepieces from
standard, please return it to normal before putting the microscope away, for the sake of the next user.
(5) If only one side of your view is in focus, bring the image into clear focus for your right eye using the
coarse and fine focus knobs. Then adjust the left eyepiece focus by rotating the knurled diopter
adjustment ring on the eyepiece. If you are an organized person, you might want to record the plus or
minus diopter adjustment that is correct for you. Similarly, you could record the correct interpupular
distance from the scale at the top of the compound scope eyepiece housing.
(6) Do your best to keep the objective lens of the compound microscope from touching the cover slip
or the slide itself. The 20X, 40X, and 100X objective lenses on our compound microscopes are springloaded, so neither they nor the slide are likely to be broken by contact, but many very good microscopes
lack this feature. The result of a collision between lens and slide can be the breaking of a slide that
represents hours of work, or altering the alignment of the lens, requiring at least $100 for repair.
(7) Form the habit of returning the compound microscope to low power before putting it away. With
our microscopes it is merely a courtesy to the next user, but with many microscopes it helps avoid
expensive lens, slide collisions.
(8) Use the various objective lenses of the compound microscope and the zoom feature of the stereo
microscopes intelligently. Don't shun the lower powers, for they show a larger field of view than higher
powers. Use lower powers for search, then switch to higher powers as needed for detail. If your
microscope is working correctly, only fine focus adjustments should be necessary after changing
objective lenses. In this and all microscope operations, please let the instructor know about
malfunctions.
(9) Match light intensity to viewing needs. Both too little and too much light can compromise
resolution. In general, higher magnifications require more light. Detail can often be enhanced in
relatively transparent material by reducing the light.
(10) With the compound microscope, learn the distinction between controlling light with the diaphragm
and controlling it with the intensity control on the side of the microscope base: When the diaphragm is
mostly closed, more of the total depth of your "thin section" will be in focus, but you will need a higher
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lamp intensity. Using high bulb intensities for everything, however, will needlessly shorten the life of our
very expensive microscope lamps. The price of increasing light by opening the diaphragm is a
progressive reduction in the total depth that is in focus. This can actually be useful if you are trying to
infer the three-dimensional shape of an object, or tell if one object is above or below another.
(11) Before turning off the compound microscope, cool the light source by turning to the lowest possible
setting for about 5 minutes.
(12) Avoid sliding the microscopes across the lab benches, for the vibration can weaken the lamp
filaments and shorten the bulb life.
Let your instructor know of any microscope problems. Effective use of the microscope is important for
much of this course.
2. Compound Microscope
Table 1. Compound Microscope Parts Checklist.
(See Figure 1.)
eyepiece housing
eyepieces (ocular lenses): 10X
interpupular distance slide
eyepiece pointer (in right eyepiece)
eyepiece micrometer (in left eyepiece)
eyepiece focus knob (on left eyepiece)
tube (lenses inside)
tube swivel lock screw
revolving nosepiece
objective lenses: 4X, 10X, 20X, 40X, [100X*]
body
coarse focus knobs (large, inner)
fine focus knobs (small, outer)
pre-focusing lever
stage
stage slide clip
in/out stage movement knob (upper)
left/right stage movement knob
aperture iris diaphragm, with lever
(lower)
base
lamp (inside housing)
condenser
lamp intensity adjustment
condenser height adjustment knob
power switch
* Will be swapped for the 4X lens when especially high resolution is required.
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Figure 1. Compound Microscope.
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Figure 2. Broadfield Stereo Microscope.
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2. Broadfield Stereo Microscope
Table 2. Broadfield Stereo Microscope Parts Checklist.
(See Figure 2.)
eyepiece housing
eyepieces (ocular lenses): 10X
interpupular distance slide
eyepiece focus knob (on left eyepiece)
tube yoke
tube yoke lock screw
upper lamp
upper lamp housing
tube (zoom lenses inside)
zoom control knob: 0.67X – 4X
paired (binocular) objective lenses
base
specimen plate
sub-specimen lamp (inside)
sub-specimen mirror
mirror rotation knob
switch for upper lamp (left)
switch for sub-specimen lamp (right)
body
focus knobs
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