SUBJECT: Ideas for plant labs (especially intro courses)
DATE: 12/95
Seasons Greetings to All,
And the season means that it is time to (re)write the lab manual
for next term. We've decided to replace our plant lab for
introductory biology (photosynthesis and plant morphology) with something
which will (hopefully!) stimulate
students to become more interested in botany/plants in general. Therein
lies the problem, what does an interesting plant lab contain or conversely
why are students so disinterested in photosynthesis and morphology? The
reasoning is to try and counter the "I really hate plants" sentiments
of
many students. I think i remember a thread about this a while back??
We have our own greenhouse with an extensive collection but i am a
little short on ideas as to exactly what would work. Possibly some sort
of touchy-feely lab or something on plant propagation. Does anyone have
experience with an exercise students like? Should the approach be to try
and cater to their like of medical/economic facts regarding plants and
build a lab around practical uses? Any and all suggestions would be
appreciated as the printer requires the manual verrry soon.
Thanks in advance to all,
Mike Weber
Dept. of Biology
Carleton University
Ottawa, Ontario
Canada
613-788-2600 (4493)
mweber@ccs.carleton.ca
We have the same attitude problem here. Many students just do not see the
point of working with plants. We have introduced some changes in our
introductory lab, which uses Brassica as the model system, which seem to
be
helping a little, although I want to see a few more semesters pass before
I
stand behind these statements completely.
Some of the changes include:
1. Introduce some protocols that make use of biochemical, biophysical, and
histochemical methods. For example, we grind up leaves in a mortor &
pestle,
add some gel electrophoresis sample buffer, and examine the protein profiles
using SDS-PAGE. If you're set up to do gels, this is very easy to do and
the
students feel they are doing "something important" with the plants.
We have
had students demonstrate the presence of two heat shock proteins in Brassica
this way.
If you can take some photos through a microscope, there are some very easy
histochemical procedures available from many of the old botanical methods
books from the 1930s and 1940s that are easy to do and give spectacular
results. For example, various methods exist to stain for starch granules,
cellulose, lignin, etc. Our students have found most of these techniques
easy to do and they can then apply them in the solution of specific
experimental problems.
2. We have groups of students work on a large project which is then
presented to the campus community as a poster session. This has turned out
to be very popular with the students in that they see their work in lab
as
being important enough to present in a public forum.
Hopefully these ideas will help. Good luck and Seansons Greetings!
George
George Edick
RPI - Dept. Biology
Troy, NY 12180
edickg@rpi.edu
We have a Domesticated Plants course that takes cuttings and grows them.
They learn about different domesticated plants and their propogation. They
really like taking cuttings and growing their own plants which they can
keep. Sansiveria (snake plant or mother in law's tongue) grows from a
small cutting of the leaf. Jade plants sprout from the base of fallen
leaves. Spider plnats are a favorite. The list goes on. The bottom line
is the student learns a little more about the plants they commonly see as
houseplants and get to take something home (literally as well as hopefully
educationally).
Brenda Simmer
Dept. of Biology
Univ. of Toledo
I like this idea! Another one I want to try soon is to ask students to
go to the supermarket in search of seeds they think will germinate. Has
anyone tried this? Also, on the plant-ed listserv someone described the
decolorization and iodine staining procedure used on a leaf that had had
a negative of a student's photograph placed over it. Apparently you can
recognize the student's image in the starch pattern.
The "I don't like plants" theme is one I hear also. However I
do get many
positive comments about using plants (we just finished an intensive
semester with Fast Plants) and I hear negatives (as well as positives)
about insects and about dissections when we do those things. As far as I
can tell there is no lab or lab material with universal appeal.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Robert B. Ketcham Biology (302) 831-2377 Laboratory Coordinator Univ of
Delaware rketcham@strauss.udel.edu
Newark, DE 19716-2590
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
A plant lab that has worked well with secondary education students through
adult week end college students has involved eating. Most people do not
relize how large a role plants play in the food web. Fruits and vegies
show different structures of plants, and you can't forget herbs and spices.
I always try to get extremely unusual or exotic fruits and vegies. So
students learn about plants and get to taste some things they might not
normally have the opprotunity in their daily lives.
Kirsten
Lab tech
kmahovl@uoft02.utoledo.edu
We have students plant seeds in our diversity class, but I
like the idea of cuttings too (I might try both next year). We
have them work in pairs to cut down on greenhouse space.
Using 3.5 to 4 inch pots, we can fit 100 or so on one bench.
Lights are helpful in forcing them to grow fast. We grow them
for 5-7 weeks; in that time the "fast plants" brassica flower,
fruit and senesce, but other plants can develop pretty far too.
We also use radishes, dwarf peas, dwarf zinnias, onions,
and timothy grass. The students keep a journal on their
plant and make weekly observations and measurements.
We tell them to look for what we study in class: apical
growth, nodes and internodes, buds, flowers, etc. We also
compare monocots and dicots. They seem to enjoy it and
often get quite attached to them- they hate thinning them
down to a single plant and often take them home at the end
of the semester.
John Dickerman
Northern Illinois University
DeKalb, IL 60115
T80JWD1@WPO.CSO.NIU.EDU
Also, on the plant-ed listserv someone described the
>decolorization and iodine staining procedure used on a leaf that had
had
>a negative of a student's photograph placed over it. Apparently you
can
>recognize the student's image in the starch pattern.
We do this experiment. In order to get the negative to work, it
has to be a high quality negative with lots of black and white contrast.
I've not had much luck with anything other than a couple of high contrast
EM negatives. This may be due in part to our 2 hour time limitation. We
usually only end up with 70-90 minutes of exposure time. The one semester
we tried to have the preceeding lab set up for the following (a true
nightmare) we did get better results with the negatives. I haven't had
much luck with transparencies either. It seems to me that they ought to
work fine. I must admit that I've only attempted a few. Our standard
procedure is to have the students cut a stencil from aluminum foil. It
works great. The oooh and aaah factor goes up when the final images
develop. --cmw
From: cwaggon@bgnet.bgsu.edu (Waggoner, Charlene)
If you are interested, this exercise was written up in the Plant Physiology
Lab
book by Carol Reiss. She demonstrated it at an ASPP meeting at least 3 or
4
years ago and used photographic negatives from past TAs in her course. Since
I
was one of them, she gave me one of the resulting prints which I have had
in my
wallet ever since. It still looks like me. I pull it out every so often
and
if students respond as well as receptionists in doctor's offices, it is
a good
exercise for capturing interest in plants!
Jon
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Jonathan Monroe voice: 540-568-6649 (office)
Department of Biology 540-568-6045 (lab)
James Madison University fax: 540-568-3333
Harrisonburg, VA 22807-0001 e-mail: monroejd@jmu.edu
www: www.jmu.edu/biology/biofac/jmonroe/jmonroe.html
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In a Botany class I took once, students were given seeds whose identity
was
known only to the instructor, and asked to grow them. We regularly made
careful labelled drawings of the growing plants over the course of the
quarter, including the flowers and young fruits. I think the suspense of
not knowing added to the experience. Overall I would say that students
enjoyed and learned from this exercise.
***************************************************
Ed Alkaslassy (503) 359-2967
Dept. of Biology FAX: 503-359-2933
Pacific University <alkaslae@pacificu.edu>
Forest Grove OR 97116
For Wilson Taylor, for inexpensive plant labs with little or no equipment,
and
other labbers who may be interested:
Mosses are great for tropism experiments. I normally grow them on an agar
medium with no glucose or other energy source but the agar itself. Half
the petri plate can be covered with opaque paper to see all the mosses
bend one direction. A table by the window would be sufficient. Funaria
is probably the best because it germinates reliably and develops quickly.
Temperatures around 30 deg C are best, as I recall, but room temperature
will do. If you don't have access to agar, gelatin would probably work,
and absolutely sterile conditions are not essential. Put lots of agar in
the plate - fill the bottom of the plate - because the agar will dry out
too soon otherwise.
Sphagnum cation exchange is another easy one to do. pH paper or a small
$50
pencil pH meter is sufficient. Mix salt solutions (.5 N CaCl2 works well,
but NaCl can be used as well). If pH in these is compared to that in
distilled water, with and without Sphagnum, the distilled water pH will
change little with Sphagnum compared to the lowering in salt because the
distilled water offers no cations to be exchanged.
Testing for starch and oils in plant or animal tissue is easy. Iodine for
the former and the latter makes paper transparent. Students might compare
parts of plants as well as various grocery store foods.
Gut analysis to identify plant types and parts is interesting for the
students. They can see what has been eaten and what has been digested.
They might also measure the pH of the gut to see if acids are available
to
help in digestion.
Pillbugs make good experimental organisms to screen for phenolics in
mosses and would probably work with other foods as well. It is fun to see
what foods they choose and try to relate edibility to habitat. Plants
that are very obvious in habitats where they live, like mosses on the
floor of a conifer forest, are more likely to have phenolic compounds to
ward off herbivory than inconspicuous plants in a field where food choices
abound.
I haven't tried cation exchange and pH changes with roots, but that is
worth a try.
One exercise I like to do is to give each small group of students a
different but not too different plant (for example, give each a different
conifer) and have them describe their plant so that when all these plants
are
mixed together the other students can figure out which descripton matches
each plant. One could then have students develop a key to these plants.
Someone suggested looking at the alga Closterium for Brownian movement.
That's a common desmid and would probably show up in samples from a
variety of aquatic habitats.
I have one lab I call adaptations. We have plants from outdoors and the
greenhouse (it's winter here at the time) scattered by groups of
adaptations on all the lab benches. Students circulate to each bench to
examine the adaptations to various conditions. We have a dispersal table
with moss capsules that perform on demand, horsetail elaters, fern
sporangia with annuli, and then various other plants with a variety of
seed and fruit types and protective mechanisms for their propagules.
Another table has sun/shade plants and adaptations to water.
Insectivorous plants and ericads are used for adaptations to low
nutrients. One table has succulents and other types of dry habitat
adaptations. We tie these adaptations in with increasing UV light and
temperatures.
I'm not sure what level of experiments etc. you are looking for, but these
should be a start.
***********************************
Janice M. Glime
Department of Biological Sciences
Michigan Technological University
Houghton, MI 49931-1295
jmglime@mtu.edu
906-487-2546
FAX 906-487-3167
***********************************
I scanned many images of plant tissues of stems, roots, leaves and flowers,
placed them either on a disk or a hard drive and instructed my students
to
create a hypercard stack of plant anatomy where they had to demonstrate
the
connection between structure and function in a root, stem leaves and
flowers. The first day they were complaining a lot, but by the second day
I
had them hooked and many of the students could be found in the computer
lab
at lunch time after school and other unusal hours
I can send the hypercard stack with all the images to anyone who uses macs.
Hans E Bauer
1050 Hillgrove rd
Sidney B.C. V8L 5R8
Canada
email habauer@cln.etc.bc.ca
Mike Weber asked about plant lab ideas for an intro course. Thanks to
help from this group, I introduced the "floating disc" method
of measuring
photosynthesis into my integrated science lab last year. Because it relys
on evacuating the air spaces in the leaves (thereby causing them to sink),
then measuring how quickly they refloat (as oxygen is generated to refill
the spaces), you can use it as an introduction to leaf structure as well
as
to photosynthesis. I have students learn the method, then test various
factors that affect photosynthesis. If you are interested, I can send the
basic instructions via email, and I am willing to share the labs (I do it
over two weeks), although you may want to change the format.
For years, we have also tested for photosynthetic activity by blowing
carbon dioxide into a solution with brom-thymol blue and adding Elodea.
BTB is blue when basic and yellow when acidic. As the carbon dioxide is
removed by photosynthetic activity, the color returns to blue. This one
takes longer, but requires no specialized equipment. I do not
have that one on a computer file, but I can sketch the outline for anyone
interested.
I find students like both of these, although there will always be some
students who don't like anything.
********************************************************************
Gail Schiffer gschiffe@kscmail.Kennesaw.Edu
Biology, Kennesaw State College 770-423-6167
1000 Chastain Rd, Kennesaw, GA 30114 Fax: 770-423-6625
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