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Seed Production and Storage
Reprinted with permission from Aa, the newsletter of The Orchid
Conservation Committee.
For additional information about the TOCC, e-mail:
elmer-spence@msn.com
or mail:
Aa
10845 97th Street North
Largo, FL 34643
Seed Production and Storage
by Wm. Paul Mitchell
The response to our request for private individuals and others to
produce seed of orchid species, endangered or not quite so, has shown
much promise. Many interesting and wonderful things have, by various means,
arrived at our laboratory. Yet it is unfortunate that we have received a
notable amount of species seed which we have found unsuitable for sowing due
to the manner in which it was harvested, shipped, and the subsequent condition
in which it was received. The opportunity to raise some intriguing and
exciting species was lost because much of the seed that was kindly donated
was too contaminated to be germinated.
Therefore, we are publishing several guides to assist those who
wish to make a contribution to orchid conservation with the production of
viable and uncontaminated seed.
As a means to conserve the resources of the TOCC, but maximize the
number of orchid species that can be propagated and eventually returned to the
wild, we urge you, the interested reader, to make careful note of the
procedures outlined within the guides below, and to follow the suggestions
therein as closely as it is practical if you intend to participate in orchid
rescue through seed production.
PRODUCING CLEAN ORCHID SEED
1) Use the best clones of the species that you are able to secure.
An inferior clone should be used only as a second choice, or if the species
in question happens to be quite rare in cultivation.
2) Sibling crosses (or out-crossing) of the same species is useful
for maintaining a wide gene pool, but if there is any doubt as to the
validity of two individual plants as being the same species, it is probably
wiser to make a selfing. Having the species identified by a recognized orchid
taxonomist can in most cases eliminate this doubt.
3) Choose fresh, fully opened blossoms whose stems (ovaries) are
clean and unblemished by any bruising, insect damage, or dark spots that
could indicate fungal infection of the external tissue of the (soon to
expand) ovary. The latter item has been found to destroy seedpods during
shipping. (Likewise, if the enlarging pod later develops such spotting as it
approaches maturity, it may be best to consider shipping the seed out of pod).
4) Before you begin the pollinating procedures, place the plant in its
pot on a clean surface such as newspaper, writing paper, or paper toweling
(preferably white). This is useful for finding any dropped pollen.
5) Use a clean toothpick or similarly shaped object, of an appropriate
size for the flower(s) at hand. The pollen is to be found below the anther
cap at the tip of the column. Look underneath the column (the surface facing
the lip) to find the stigmatic cavity, a recessed area near he tip of the
column. At the end of this cavity nearest the tip will be a small flap
hanging down to which the pollinia (pollen masses) are attached; the pollen
will most likely not be visible at this time. Touch the toothpick to this
flap, which is sticky, and force it gently forward, away from the stigmatic
cavity. The flap is sticky and will adhere to the toothpick, withdrawing the
pollen masses. Sometimes this flap may have dried out and will not be
sticky. If this is so, first touch the toothpick to the surface of the stigma,
which is sticky too. Then use it to lift the flap with the pollinia out of the
flower. The poellen masses may then be inserted into the stigmatic cavity,
where its sticky surface will hold the pollen firmly. Now pollinated, the
flower will begin to fold after a few hours.
6) IMPORTANT: Please label your pollinated flower! Do _NOT_ rely
upon memory. The necessary information should include, for selfings: the
correct name of species, with any clonal or award names; if a sib cross, name
of the second (pollen) parent of that same species, with its clonal names and
awards, if any. Labels should also include the following: date of pollination,
the position of the flower on the inflorescence (sometimes very useful after
the other flowers have fallen). It is often customary to record the name of
any person from whom pollen was obtained, in case they request a few seedlings
in return for stud service, or simply for reason of keeping track of the
location (in your own records) of the pod parent for later reference, if
needed. It is also important to know the owners of both parent plants for
record keeping in regards to genetic variability for later breeding with
the seedlings produced.
SHIPPING ORCHID SEED IN GREENPOD
1) Greenpod denotes a mature, but still unopened, seedpod. The
green seedpod is the ideal container in which to ship orchid seed. As long
as the pod is closed, the seed in it will remain sterile, which is of the
utmost utility. Such pods must be cut from the plant at the last practical
moment, then shipped by the quickest method. The TOCC labs must be advised
IN ADVANCE that a greenpod is being sent.
2) To send a greenpod, first check it carefully to be certain that
it is sill sealed. Thoroughly examine the pod for scale, snails or any
other types of pest, and remove them if found. Cut the seedpod from the plant
with a clean, very sharp knife, without shredding or bruising the stem. After
the pod is cut, wipe it lightly with alcohol or other mild disinfectant and
dry it carefully; this is doubly important if the pod has developed any
black fungal spots during its maturation period.
3) Seal the cut end of the stem (be sure to cut well below the area
where the stem has begun to swell) with a drop or two of candle wax to slow
the drying of the pod tissues, and to prevent contamination via the stem. This
can help keep the pod from opening too soon if it must travel a great distance
in the mail. (Also please remove any old or dried flower parts, which could
contaminate the seed should the pod split during transit.)
4) Place the prepared pod in a paper envelope and seal all edges
with cellophane or masking tape, being certain to leave no gaps. If this is
not done and the pod should open en route, much seed can be lost due to its
minute size. Use no plastic wrap or any type of plastic baggie which retards
air circulation and holds moisture, both of which can cause the enclosed pod
to decay or split. The sealed envelope should be placed into a small, sturdy
carton with newspaper or slightly loose packing to support it. MAIL IT BY
EXPRESS OVERNIGHT MAIL to avoid spoilage due to otherwise slow handling.
5) Pods traveling in from abroad should be placed in an envelope and
sealed as described in 4, above, but the most certain way to ensure its
arrival in our hands is if you can arrange for someone who is travelling
to the USA to courier it on the plane to us for you. If their destination
is not near us, then you can have them overnight express it to us, as this
service is easily avaliable in all major airports. Note that orchid seed is
essentially exempt from the CITES restrictions imposed on the orchid plants
themselves.
STORING SEED OUT OF POD
Occasionally a seedpod will open unexpectedly or may suffer inflicted
by insects or animals. When the pod is breached, it is no longer sterlie and
the seeds inside, while still viable, are most likely contaminated. Should this
occur, the seed must be removed from the pod and stored in a cool, dry place.
A clean room without drafts is an ideal place to accomplish this.
Place a clean sheet of paper on a flat surface. Cut the pod open gently
at right angles to its length with a very sharp knife. The pod alternatively
may have to be split open along one of the ridges that runs its length,
where it would naturally split. Tap the seed gently out of the pod onto the
piece of paper. Again, try to remove all old flower parts before harvesting
the seed, and be very sure no small pieces of the pod fall into the seed.
This type of contamination is too small to be seed, and cannot be sterilized
by any current methods.
Divide the seed into as many portions as you will need, then wrap
each portion into a separate 3" x 5" piece of paper using a pharmacists'
fold. Tape all open edges of the packet. Seed may be placed in small coin
envelopes instead, also making certain that the edges are securely sealed with
tape.
Now, label each packet or envelope with all pertinent informatino about
the seed that was on the label from the seedpod. Include the native origins
of the species or where it was collected, if known.
Place the packets into a suitable container that will hold them and
place a small packet of drier, such as calcium chloride, in the container
with them. The dessicant must not be in direct contact with the seed! The seed
may be refrigerated, but MUST NOT be frozen!
STORING ORCHID POLLEN
Most orchid pollen may be stored in the same fashion as described
for orchid seed, as noted above. Be certain that all pollen is bright,
and not gray or discolored. Discard any that is.
Wrap and label orchid pollen as described for orchid seed. Most
pollen will last approximately six months, although the pollen of certain
genera has a viabiliy of only days or weeks.
SHIPPING ORCHID SEED OUT OF POD AND SHIPPING POLLEN
Orchid seed prepared as described above should be kept cool until
the time of shipping to minimize deterioration. When ready to ship, place
packaged seed in a suitable non-plastic container, as described for
shipping seedpods, and ship overnight express mail. An alternative is to
place the seed into a regular mailing envelope and send through regular mail.
Mark shipping container "ORCHID SEED- PERISHABLE". Orchid seed is exempt
from CITES restrictions from abroad. Alternatively, arrange with someone
traveling in our direction to courier the seed to us as described above.
Orchid pollen may be shipped in the same manner as orchid seed.
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