Kitchen
Plant Tissue Culture
Brief How & Why of
Home Tissue Culture
by Bob G. Cannon II
While in the process of setting up workshops for plant tissue I have
been asked a lot of questions. Most frequent are what advantage TC
might have and how it might be done without spending a fortune on a
laboratory. What follows attempts to offer answers to some of the
questions I have been asked.
First let me say what Plant Tissue Culture (PTC, TC) is not. It is not
against nature and not genetic engineering. It does not have to be
particularly expensive or dangerous. Like grafting, gardening and
changing the oil in your car you do need to follow some standard
directions. Since TC started as an expensive laboratory process,
requiring quite a bit of technical knowledge many of the terms used
with it stem from this – for example we don’t say the directions for
making a TC of African Violet but the protocol for African violet.
Most of us know that some plants will grow from cuttings – TC, in it’s
simplest is using a plant’s ability to reproduce from cuttings on a
very small piece of the plant. Plants from TC are identical to the
parent plant, just like an airlayer or cutting. When you make an
airlayer or cutting of a plant a Botanist or Horticulturist will
usually call this plant a clone of the parent, TC plants are clones of
their parent plant. In the garden we snip off a 2-foot branch and
thrust it into the ground and it may grow. With TC we might take a part
of the bud at the tip, or a part of a leaf and use it to produce a
number of new plants. Since the ‘cutting’ is very small special care
needs to be taken to keep it alive long enough to make new plants.
Grasshoppers and cutworms are not so much the enemy as fungus and other
diseases.
Why Plant Tissue Culture?
Most new plant varieties come about because someone planted a seed and
it grew into a plant whose fruit (or root or leaves) were different in
a desirable way. Sometimes new varieties come about due to a mutation
that occurs in a plant. (Pink grapefruits started this way, from a
single branch on one tree in an entire grove of standard white
grapefruit).
If a seedling variety is different enough someone will want to
propagate it. It might be propagated for profit of to just spread the
new plant out into the world. TC is useful here in that you can get a
large number of identical plants quickly, once you figure out the
protocol.
As an example: I like Hippeastrum (Amaryllis) and sometimes
cross-pollinate them. Suppose I got one that had a rich blue flower,
how would I propagate it to make enough to sell? I could grow the bulb
and then save the offsets and cut the bulb in hopes of building up some
stock over time. To get 10,000 clones would take years. I could also
use TC to produce my new bulbs. With TC I would have my new bulbs much
quicker.
Another reason to use TC is preservation of endangered plants. Using a
part of the last known living xyz plant thousands of new plants can be
produced. These can then be planted in the natural range of the
endangered species and spread throughout the world.
Some plants grow naturally and produce only male or female flowers,
these plants are called dioecious and must have both sexes to produce
seed. I know of a few plants where there is only one known sex living.
These plants must be produced by cuttings or layers, as no seeds are
possible. TC is also a good alternative. The most popular plant I know
that is found as only one sex are some of the Lady Palms: Rhapis
humilis are all male while Rhapis laoensis are all female. You might
cross-pollinate them but any plants resulting from the seeds will be a
hybrid combining elements from both of the parents.
Here is a last reason to use TC is more difficult to define. It can be
fun. FUN? TC can be just as much a fun and rewarding part of
horticulture as growing orchids, a home garden or (in my case) rare
fruit. I have known people who, being dedicated to their ‘special
plants’ spend decades working to grow them. Some spend far more than
they will ever get back from their plants – unless you consider the
rewards of success. The late William F. Whitman spent decades importing
and
growing rare tropical fruit that everyone knew would never grow in
Florida. He, and other rarefruiters, helped bring new edibles not only
to the USA but the world. If you have eaten a ‘starfruit’ or carambola
in North America Bill, and a couple of other gentleman (Dr. Robert J.
Knight, Morris Arkin) had a hand in putting it on your table. Bill grew
his plants for fun, so did Morris.
Some readers may be in the same category of the men mentioned above,
either they made plants their only job or their plants were a second
job. Said another way — plants became their passion.
The How’s of Tissue Culture
The easiest way to get a plant into TC is to find a lab and hire them
to do it. Not much fun in that and it can be costly.
The fun alternative is to set up your own lab. With your own set up you
can participate in the joy of producing your own plants. You can work
at your own pace, limited only by finance and the growth habits of the
plants.
One of the most rewarding setups for the hobbyist and new professional
is a home lab. Your home lab might be in a spare room or garage or it
can share the space with another function. Carol M. Stiff, PhD has
developed a business and an entire course aimed at those who might use
their kitchens. Her Kitchen Culture web site, kits and workshops have
introduced many to a fascinating new hobby. Some have even gone on to
commercial labs or projects. By the way, the Home Tissue Culture Group
has available all the special chemicals and equipment you need to start
at home. They even sell the book Plants From Test Tubes to customers at
cost. Their link is on Carol’s web site.
In a home lab the autoclave is replaced by a microwave or pressure
cooker, disinfectants are found at the local store (bleach, hydrogen
peroxide) and other lab equipment is improvised or done without.
Recycled bottles become glass vessels for growing plants – baby food
bottles are especially popular for this. You may also need sugar,
baking soda, vinegar, water… Only a few additional things need to be
bought that cannot be found in a grocery or drug store.
To grow a plant
by TC you first need to find out is someone else has already grown it
and published the protocol (directions). If they have, your task is
simplified some as you know what worked. (You may still need to make a
few alterations to get the best results). If you can’t find a protocol
for your species of plant look for one for the same Genus or close
relatives. You may be able to adapt one to your needs.
Assuming you have gathered any lab equipment, and found a protocol you
have to choose your plant. Just as you would not make cuttings from a
diseased plant your TC plant needs to be healthy.
What part of the plant you need depends on several things. Generally if
you found a protocol that used material from a leaf you would not use
material from the roots – unless your goal is to see if you can produce
plants from the roots. Most of the time the plant donates a small
portion and is not adversely affected. Most plants can lose a leaf or
tip without great damage. You may already have pinched off a leaf from
an African Violet, Begonia or Peperomia to use to start a new plant;
the parent hardly noticed the loss. There are exceptions, banana being
one.
To get good material for TC with a banana you generally dig up the corm
and cut off the growing point. Preferably you use a “pup” for tissue
culture rather than destroying the mother plant. This is cleaned, and
trimmed down several times.
I have often taught that in the grove or
greenhouse cleanliness is extremely important. In TC it is paramount
and it is worth quoting John Wesley twice: 'Cleanliness is indeed next
to godliness' - 'Cleanliness is indeed next to godliness'! You need
clean plant material, clean growing areas and might even take a bath
and put on clean clothes before you start a TC project. Anything you
get into a culture is contamination and contamination is the main
reason TC fails.
Clean plant parts, clean equipment, clean air, clean you. To get clean
air many use a makeshift glove box or clean box, no need
for a laminar flow hood. If you have grown orchids from seed you know
about a clean box. I have seen them improvised in many ways, including
fish tank, and clear plastic over collapsible PVC pipe frames.
The next step is to place your prepared plant material onto the growing
medium. Growing medium? Uh oh what is this? Chances are you have
planted seeds in a seed mix or cacti in a cactus mix, medium is just
the TC term for the same thing – a specialized mix that gives the plant
material the best chance of survival and growth. To give the details of
growing this into tiny plants or explants is beyond the scope of this
article and one of the reasons I suggest taking a workshop.
You can’t really take the science out of tissue culture, but you can
simply the process and methods so that you do not need an expensive lab
and a Ph.D. for success. If you want to give TC a try you may want to
know some of these terms below.
PTC is done on various plant parts including:
Buds
Stems
Leaves
Roots
Corms
Bulbs
Each plant part has special requirements and may have its own method
name. For example TC using a bud (growth point of a plant) is a
meristem culture.
Medium — what you grow the plant material in. Mediums are frequently
given exotic sounding names (usually after the people who first made
them) the most popular seems to be Murashige & Skoog (MS) which
is
modified many different ways depending on the plant. The medium
contains what the plants need to use as they grow, much like garden
compost.
When you grow a tiny developing plant in a culture it is called an explant. This is just another stage of
growth in the plants life similar to growing fern from spore and
watching it pass from gametophyte to sporophyte.
Protocol — the directions methods or techniques used to TC a particular
plant. Some protocols can be difficult to locate. A good place to start
is with someone with wide experience. If all else fails, or you want to
save some time, drop Carol an email and she probably has a reference or
knows someone who has cultured your plant.
Botanical Name, Latin Name or Binomial — the scientific name of the
plant. When looking for information about a plant on the Internet, or
in research publications it sometimes is better to use the Latin name
for a plant to avoid confusion. The two parts of the name are the Genus
and species. (This is reversed from peoples names in North America as
the species name is equal to a given name). An example might be in
searching for a protocol for African violet. Many different flowers
have daisy as a part of their common name and the protocol that works
for one may not work for another. Some countries may not even refer to
the plant by the common name. The scientific name you want is most
likely: Saintpaulia ionantha or Saintpaulia spp.
Many plants are named after their discoverers and African violet is
named after a German Baron, Walter von Saint-Illaire, who discovered
the plant in East Africa.
If you cannot find a protocol for the species or Genus (it is always
capitalized) sometimes looking for members of the same Family helps.
African violet is in the Gesneriaceae – in most of my botanical books
family names in all caps to emphasize their importance, GESNERIACEAE.
Almost all family names end in aceae or ae. (SOLANACEAE = tomatoes,
peppers, potatoes, tobacco; PALMAE = coconut, jelly, ivory, parlor
palms). A plants scientific name is forever – unless it gets changed!
This same basic system is used for all living things. (It was
formalized by a talented Swedish man (Botanist, Doctor and Zoologist)
in the 1700’s. His name was Carl von Linné although you may see it as
Carl Linnaeus. Using his system he Latinized it to: Carolus Linnaeus,
which also appears. A full copy of the code can be found at the site
below. It is NOT light reading:
http://www.botanik.univie.ac.at/iapt/s_ICBN.php
One last thing on
using scientific or proper names: Scientific names are nothing to be
ashamed of, it is not putting on airs to use them. BUT if you insist on
using scientific names exclusively, and correct all friends who do not
share your enthusiasm you risk leading a solitary existence. Sometimes
it is best to let a peach be a peach and not Prunus persica!
Can Plant Tissue Culture create problems?
Yes, if misused. And almost anything can be misused. In the case of
home PTC the chances are not very high and the techniques and chemicals
used in a home lab are mostly already in your home. Some commercial and
other
labs combine it with genetic engineering and a lack of proper safety
protocols. I believe that this is due to a shift in research from
academic control to profit motive control. You are free to disagree but
I note that gene modified corn, soy and papaya contaminate several
growing areas. Understand that it is a lack of proper safety protocols
and not the act of genetic engineering in and of its self that is
causing concern. Technically when you do any selective breeding you may
be practicing genetic engineering. It is a very political area.
So, is Plant Tissue Culture for you? Do you think it might be fun or
want to give it a try for the possibilities it opens up? If so, I
suggest you consider taking a workshop and the best one I know of is
given by Carol Stiff. I am in the process of trying to set up one now,
and may try for others in the future. Take a look at the details:
Some Links:
Previous
Page
Carol’s Kitchen Culture site: www.kitchencultureEducation.org/
Rare Fruit Site:
www.quisqualis.com
Information on any TC workshops I may be organizing or know about: Carol's site and right here at: www.PropagatingPlants.org