Most exciting topics in Plant Biology

Grant R. Cramer cramer at MED.UNR.EDU
Fri Aug 15 17:00:09 EST 1997


Dear Readers,

The responses to my questions were very good and very helpful. Thank you to
those of you who responded. There appears to be a number of you who had
similar experiences. Some of my favorite ideas were:

1) Making a contest out of growing plants over the semester and giving  a
prize at the end of class.

2) Showing the "Private Life of Plants" video series by David Attenborough.
I will probably only use excerpts. You can obtain this 6 part video series
from the PBS website for $79.98:
http://www.pbs.org/store-cgi/store/vMFkUUcCwR?alpha=3D1.

3) Presenting stories about plants to illustrate their importance in our
society. Particularly noteworthy was the recent article by Wade Davis on
"The Rubber Industry's Biological Nightmare" in the Aug 4, 1997 issue of
=46ortune Magazine and the First  Chapter of Henry Hobhouse's book the "Seed=
s
of Change" on the history of Quinine and its impact on the world. Perhaps
another area of interest not mentioned by anyone is the recent interest in
Red Wine and Heart Disease (a good article can be found about this on the
U.C. Davis, Dept of Vit. and Enology Web page:
http://wineserver.ucdavis.edu/VEN11.HTML)

Also you might note that ASPP has recently developed "12 Principles of
Plant Biology" which may be helpful in designing course material. You can
find them at this website: http://www.aspp.org/edfn/prin12.htm


=46or the benefit of all, here were the replies in their entirety.

Response #1
I co-teach a sophomore level course for biology majors called "structure
and function". In its current iteration, it includes some cell biology,
some animal physiology and some plant biology. Unless students take an
upper level plant physiology or development class, this is the only
exposure they get to plants. I also need to try to show them that plant
biology is a lot more exciting than they think.....
I have only 8 75 minute lectures in which to try to do this.....
At the very beginning of the plant section I give them a five minute on of
plant evolution, explaining that we're only going to discuss angiosperms as
they are the most common and most familiar and most important kinds of
plants. The lectures then are:
Plant cells, tissues and organs
Transport
Photosynthesis
Plant nutrition
Plant development
Plant hormones
Reproduction
Stress and response

They basically sleep through transport and photosynthesis, but seem to
enjoy the other topics. I won't eliminate photosynthesis, but I'm thinking
of getting rid of transport....

In cells tissues and organs, I end the lecture by having the students come
to the front of the class and examine (and rip apart) a variety of plants
(mostly from the grocery store). This is always a big hit.

Nutrition is fun for them as they are intrigued by symbiotic nitrogen
fixation and of course carnivorous plants. I also talk about fertilizers
and how modern farming is done.

They seem to enjoy phototropism and gravitropism (I've brought in etiolated
corn so they can see the coleoptiles)
I have a time-lapse video of germinating seeds of several species which
they usually enjoy.

I find most of them are unaware that plants have any stress responses, so
that is generally interesting to them.

When I talk about reproduction I bring wild and cultivated flowers to lab
and let the students dissect some of each. They're usually surprised to
hear the term "dissection" and "plant" in the same sentance, and they seem
to get a kick out of pulling off organs under the dissecting scope.

One thing I've found helpful is Scientific Amerimcan articles - they seem
to be at the right level for these students are are pretty good at
conveying the researchers enthusiasm. I can send you a list of the ones
I've used if you're interested.

Within the context of many of the topics, I talk a bit about mutants and
molecular biology. Although they haven't had formal courses in genetics or
molecular biolgy, they are generally enthusiastic about the approaches, and
I think these approaches make plants seem more "modern" to them......

Since this is a very basic course, and plants are only a small part of the
course anyway, I use their Introductory Biology textbook. They've bought it
already, and they haven't read the plant chapters yet. The book we use
"Life: the science of biology" by Purves, Orians and Heller, is very good
in the plant chapters (Bill Purves is a plant physiologist).

I hope these ideas help, and I'll be glad to share any specifics with you
or answer any more questions. I've found their responses to the material to
be very postive, even though most of them don't feel "plant-oriented" going
into the course.


Response# 2
Try showing how plantr disatributions show evidence that evolution works
and that continents move.

Response#3
I was in a similar position, developing a plant bio course: the plant
phys course I was (partly) hired to teach drew few students mainly
because there was no course that gave them the basic material of plant
biology-- so I dropped the physiology course, implemented the plant bio
course, and it has gone quite well.

Don't forget to include your own interests as one of the criteria for
choosing themes and topics.  Your interest will come across and
illuminate the course.

The selection of topics that I have used depends crucially on the other
courses that our students have had.  So, for instance, I know that they
have all had a good cell biology introductory course, as well as a
limited survey of the plant kingdom in the other intro course; genetics;
and would almost all be taking biochemistry concurrently.  So on the
physiology side, for example, I skip the basic material of glycolysis,
respiration, and photosynthesis.  Instead I move more directly into
photorespiration, the glyoxylate cycle, and C4 & CAM metabolism.  This
would have been preceded by an intro to transpiration and translocation.
Throughout, I emphasize the connections to how plants make thier living.
So, also, presenting physiology comes along with presenting the
ecological contexts that make sense of it-- life in the desert, etc.

This goes to the more essential themes of the course.  The first day, I
tell the students that my goal in the course is to change the way that
they think about plants-- in fact, to make them able to "think like a
plant".  This seems to work well-- not as a device, but as a theme.  So,
for instance, the glyoxylate cycle becomes not just another intimidating
metabolic cycle, but true magic of life, elaborating compact carbon into
expanding molecules of a germinating seedling.  Metabolism is not just
producing energy, but balancing the needs of producing cellular energy
and cellular building blocks to make stuff.

Another theme that I use is to explore the role of plants in human
history-- the topics ususally done (well?) as "economic botany" or "why
study plants".  I lean heavily on Henry Hobhouse's _Seeds of Change_, and
go into detail of the stories (and I tell them as stories, as he does) of
the roles of several plants in human history.  Like good stories, they
have characters, conflicts, crises, surprising connections, and
denoument.  I do it by taking every other Friday as "story day", and tell
one plant's story each time.  It is the students' favorite part of the
course.  I fret, of course, over the "biology" material that I give up
instead-- but shouldn't.  I am not trying to "cover" plant biology, but
make the students want to learn and care about plants for the rest of
their lives.

I also show some of the great movies from the series (help-- I forget the
name of the fellow who did them)-- I think the title is "The Private Life
of Plants".  I think he had a blank check to make the series, and it is
full of top-notch time-lapese photography.  Goes over very well.

What I don't do is: I don't go through a textbook from chapter one to
chapter N.  I want them to use the text as a tool, not a crutch.

If you go into the classroom with your delight in the students and in
plants each day, you can't go too far wrong.

One idea that I got from this bulletin board is to give each student a
Kalanchoe plantlet and then have them raise the plants on their own, the
student with the largest one at the end of the course winning dinner for
two anywhere in town.   This is fun, and it makes them pay attention to a
plant.  We also have prepared labs, and they design their own projects,
too.  Every time, I swear I will not do that again (enormously time
consuming, and the students have to get going on the projects so early
they have little useful imagination about wwhat to do, how, etc.-- they
need lots of guidance but need to retain ownership over the ideas and
efforts, etc.)  but I always end up doing it, and it always seems worthwhile=
=2E

Whatever you do, you won't cover enough of the basics.  You won't, no one
does, no one can.  You are just starting the students on something they
will, in some way, keep at in many ways for a long time.

Response #4
	You asked about essential topics for an introductory
plant science/botany course.  Here are some ideas that occur
to me.

	Emphasis should be placed on evolution.  For my
money this involves giving students a good understanding
of the alternation of generations of plants, and getting
them to the point where they can compare this life cycle
to that of the algae, especially the green algae.

	A good text is BIOLOGY OF PLANTS (5th edition)
Worth Press, By Raven, Evert, and Eichorn.

	For a good perspective you might wish to look
at Karl Niklas's recent text, Evolutionary Biology of
Plants.  He covers the species question, and adaptive
morphology in a way that this "dumb" plant physiologist
can incorporate these ideas in my lectures.  This text
is a good resource for the instructor, but is too
advanced for freshman.

	For good topics to hook students, and some ideas
about lab exercises, you might look at 	THE ACTION PLANT,
by Paul Simons.  I give a "senses of plants" lecture each
year based on information I got from this text, and this
information has caused some students to rethink their
definition of plants.

	I also include some anatomy and morphology in my
intro botany course.  Enough so that students know the
basic cell types, and so that they could begin to use
introductory keys.  We cover the basic organs, and then
we discuss variations by doing a fruit lab.  We pull in
every type of fruit and vegetable I can get from the
supermarket, and students have to study these and determine
what organ(s) they are!

	You can do many fun exercises with moss and fern
spores growing into gametophytes.  And I have students
plant Mimosa pudica, the sensitive plant.  Mimosa seeds
are available from Wards, and you can improve their
germination rate by a brief (1-2 min) treatment with
hot water.  So I have students do a control and heat
treated set of plants.  Students are then able to have a
set of plants they can take home at the end of the semester.

	If you have access to parks or woods in the area,
or arboreta, you might consider a field trip.

	The over arching theme should be evolution.  With
the diversity of plants as examples.

Response#5

I think leaving the anatomy and physiology until last is smart.  I have
often done the traditional textbook progression from cells to tissues to
plant parts, and until you get to the plant parts, it's dull for students.
An approach which I've enjoyed in discussing topics like "stems" is asking
what purposes stems have, (e.g., moving a plant up into space to compete
for sunlight, support) and then looking at the adaptations that make that
possible, such as a water-based "skeleton", reinforcement w/ lignin, etc.
I run a mini (2 minute) contest where students try to cut the longest
piece of paper they can that will hold itself upright, to show that
cellulose alone isn't rigid enough to hold stems up.  Anyway, the
function/adaptation approach is one that I like and that goes over well.
It's not usually laid out very well in textbooks though.

Photosynthesis and respiration are not big favorites even though they're
so important.  Maybe approaching them in either an ecological or practical
context (greenhouse climate/air control?) would help.

Do you know the video series The Private Life of Plants? 6 videos narrated
by David Attenborough which look at various activities of plants such as
dispersal, defenses, pollination.  Great footage, lots of time lapse
stuff.  They are the only hour-long videos I've shown in any class I teach
where at least most of the students pay attention and don't need to have
worksheets or quizzes to keep them focussed.  I show all 6 during various
labs just for a break.

The august 4 1997 issue of Fortune Magazine has a very good article on
rubber.  Very few cultivars are used, and there's a devastating leaf
blight that could take them all out... Irish potato famine scenario.

Response #6
Attached is a copy of the syllabus from my botany course, hopefully
readable without its fancy formatting.  I have a philosophy similar to
yours and wrote my own book because I could not find what I wanted.  I
likewise start with an overview of the plant kingdom, but don't have the
luxury of a field trip because it is the middle of winter.  Instead,
students are required to find at least 40 items from a scavenger hunt
list.  It gets them out in the field when spring starts to break through,
and the list includes such things as find a plant that has C3 metabolism,
or nodules, or produces archegonia or has an epidermis, etc.  Ours is a
10-week term.  We have a field trip the last week.

        SCHEDULE

WEEK 1
LAB 1
        Microscope and Overview (Micro & lab 1)
        Use of microscope
                parts
                micrometer
        Overview of plant kingdom (lab 1)
                Describe plant provided
                Major divisions
                          (survey mixture)
                        flowering plants
                Use computer to key out divisions
                Sporophyte vs gametophyte
                  non-vascular to vascular
        Skills (20 points)
                use slide projector correctly
                identify plant with computer key
LECTURE 1-1
Introduction (Introduction chapter)
        examples of plants in current news

        define plant
        plant body __ sporophyte or gametophyte
        review meiosis
LECTURE 1-2
        plant classification
                naming system
                review divisions
                1n, 2n
                conifers vs flowers
LECTURE 1-3
        basic plant anatomy (organs)
                roots __ regions
                entry of water
WEEK 2
LAB 2
        The green plant: anatomy and conduction (lab 2)
        vascular plants
                vascular bundles
        conduction
        Anthophyta
        monocots vs dicots
                cotyledon
        non-vascular plants
                Bryophyta __ gametophyte
                stem cross section
                rhizoids
                conduction
                internal vs external
        key to shamrocks __ plant parts
        set up nutrient experiment (part I of lab 7)
        mock practical
        Skills (13 points)
                make thin section of moss stem
                drawings
                use of pipette


                ground tissue
                rhizomes

LECTURE 2-1
basic plant anatomy, cont.
        monocots and dicots
                leaves
                xylem, conduction, stoma structure
                properties of water
                transpiration-cohesion-tension
                diffusion pressure deficit
                wilting, transpiration
                                bacteria prevent crystals

LECTURE 2-2
Essential nutrients __ the gases (Chapt. 1)
        macronutrients
        micronutrients
        plant needs for CO2
        C3, C4, and CAM plants
                CO2 concentration

LECTURE 2-3
                temperature effects
                herbivore effects
                light

WEEK 3
        C3, C4, and CAM (lab 3)
                slides of corn leaves
                slides of wheat leaves
                exp with corn & wheat
                examine monocots
                CAM plants
        set up nutrient addition experiment (lab 7, part III)
        lab practical
        Skills (6 points)
                use of pH meter
                epidermal peel

Write 1-page report on C3/C4 experiment and guard cell response to salt

LECTURE 3-1
        greenhouse effects
        guard cell control & function
Oxygen & Ozone (Chapt. 1)
        photosynthesis
        aeration
        natural ozone
        Christmas tree damage

LECTURE 3-2
        palisade membrane damage
        ozone and UV light
                protection of meiosis __ sporangia
                gametophytes
                protection during dispersal
                dispersal mechanisms

LECTURE 3-3
                avoidance strategies & filters
                antenna pigments
                high elevations
                snow algae
                excision repair

WEEK 4
        Plant adaptations (lab 4)
        (high light & drought adaptations)
                        plant susceptibility
                        leaf sheath
                        glandular hairs
                        plant protection
                        vertical leaves
                        hairs
                        waxy cuticle
                bog plants as xerophytes
                aquatic adaptations
        spore protection & dispersal
        replace dead tomato plants
1-page report due

LECTURE 4-1
        sun & shade leaves
        xerophytic adaptations

LECTURE 4-2
Pollution sensitivity (Chapt. 2)
        definition of heavy metals
        heavy metals & ion exchangers
                Sphagnum
                soil
                leaching
                roots
        copper deficiency and excess
        plasmolysis

LECTURE 4-3
        SEMINAR __ bryophytes in man-centered world

WEEK 5
        Biomonitors & heavy metals (lab 5)
                bryophyte life cycle
                        moss examples
                        protonema plasmolysis
                cation exchange
                        in Sphagnum
                        Pelargonium
        Skills (5 points)
                sterile inoculation

PRACTICAL (Thursday evening)

LECTURE 5-1
life cycle sensitivity __ moss life cycle
        horsetails __ rhizomes

LECTURE 5-2
Red tides and heavy metals (Chapt. 3)
        dinoflagellates
        chelation
        Ptychodiscus brevis
        Gomphosphaeria aponina
LECTURE 5-3
Acid rain (Chapt. 4)
        definition
        frost hardening
        forest impact
                growth rings
                loss of potassium
                chlorophyll damage
        sandy soil =A2 leaching

WEEK 6
                lichens & SO2 pollution
                        lichen types
                        lichen anatomy
                        chlorophyll damage in lichens
                woody stem anatomy
                look at protonemata (lab 5)
        re-inoculate moss if not successful
LECTURE 6-1
        lichen sensitivity __ symbiosis
        lichen structure & types
=46ertilizer nutrients (Chapt. 5)
        nitrogen in atmosphere
        nitrogen deficiency
        Cyanobacteria

LECTURE 6-2
        nitrogen fixation __ Cyanobacteria
        PS I & PS II

LECTURE 6-3
        nitrogen fixation __ Rhizobium
        insectivorous plants

WEEK 7
        Nutrients (lab 7)
                hydroponics (read for lab)
                nutrient deficiency (part II)
                        analysis of mineral deficiency
                nutrient excess (part IV)
                        algal nutrient studies
                        identification of algae
                        duckweed
                adaptations to low nutrients
                        insectivorous plants
                        Rhizobium slides
                        Azolla symbiosis
                        Chlamydomonas
        Skills (6 points)
                locate live diatoms on slide
                locate live Chlamydomonas

LECTURE 7-1
Nutrients and aquatic productivity (Chapt. 6)
        sewage algae __ Annie, Fanny, & Mike
        duckweed

LECTURE 7-2
Useful & edible algae (Chapt. 7)
        Spirulina
        Chlorella
        Chlamydomonas & soil retention
        diatoms
        Phaeophyta
        Rhodophyta

LECTURE 7-3
Deficiency symptoms (review lab results) (Chapts. 5 & 9)
        translocatable
Reducing nutrient competition __ herbicides (Chapt. 8)
        Paraquat __ contact, desiccation, light sensitive
        2,4 D __ hormones (IAA, ethylene), translocated
        Roundup __ translocated
                ethylene
        natural

WEEK 8
                          nori
        Begin collections for scavenger hunt
        Skills (3 points)
                titration

LECTURE 8-1
Edible plants (Chapt. 10)
        edible parts
                roots
                rhizomes
                tubers
                bulbs
                stems
                buds
                leaves
                petioles
                flowers
                fruits (ovaries, carpels)
                seeds
        dump-heap theory
        monocots vs dicots
        grains
        parts of fruit
                ovary, carpels, ovules
        seeds
                endosperm
                 double fertilization
                aleurone layer in seed

LECTURE 8-2
        wheat
                lodging, too healthy, needs ethylene
                ripening

LECTURE 8-3
Pollination (Chapt. 12)
        flower parts
        monoecious, dioecious, perfect
        fertilization

WEEK 9
        Pollination and attraction (lab 9)
                plant pigments
                pollination
                        live plants for pollination types
                        Yucca, Asclepias
                        lily pollen and stigma
                bring flowers to lab
                check scavenger hunt items
        Skills (3 points)
                paper chromatography

LECTURE 9-1
        types of pollination
                wind __ trees & grasses
                gravity __ corn pollination
        types of pollination
                water __ tape grass
                bird
                bat __ banana
                insect
                        beetle __ magnolia, daisies, duckweed
                        butterfly __ poor pollinators
                        moth __ yucca, cacti
                        fly __ skunk cabbage, Dutchman's pipe

LECTURE 9-2
                        bee __ milkweed, orchids
Plant propagation (Chapt. 13)
        seed dormancy

LECTURE 9-3
        vegetative propagation
review

WEEK 10
        field trip & scavenger hunt (lab 10)
        review
        Final Practical (Thursday evening)

LECTURES WEEK 10 (night tests were given with no class time off, so week
10 was used for recapitulation - that way everyone could benefit from a
review instead of having it at night when students might have conflicts)
Lab review
Celebration?





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