OrchidSafari ARCHIVES*

Stem props provide a way to encourage adventitious growth in an orchid. In props, we flask a portion of the bloom spike under sterile conditions just as we would seed. The resulting plant is no different than one we might induce chemically with one of the purines, BAP (benzyl-amino purine) for example, or find naturally on something like P. equestris.

Flower stems can produce a keiki (Hawaiian for child, hence a small or new plant) at the same node points they might produce a secondary bloom spike if the spent flower portion were removed. Only such nodes can produce a plant or secondary spike; the abscised portion of the spike, where the old flowers have dropped, has done its do and won't produce new material. Stem props, however, can be produced from juvenile bloom spikes. Best take on a Phal stem prop will be with a very young spike. Still, one can cut a lot of prop sections from an old stem and the rate of growth is pretty fair.

If you plan to do stem props, remove juvenile spikes right at the plant just before the buds begin to clearly differentiate. If using a bloomed spike, harvest the whole spike while it still has good flowers. When flowers drop, the stem undergoes some drastic aging changes above the node next to the flowers. We don't need any of that influence working down into our useable nodes. On an older spike, harvest the spike and remove the bloomed portion down to a point just below the first flower scar. With a young spike, get all the spike you can and remove the bud portion, losing as little stem as possible. If you work with an intermediate spike that has not bloomed but has fully elongated, you might get two or three good nodes; on a very young stem, usually just one. Separate the stem into segments so a node is in the lower (plant side) third of each segment. This will remind you of "up" and also give you a good grip to tweezer the prepared prop into the medium.

Clean the prop by removing any loose tissue and by carefully removing the bract tissue covering the little bud at each node. It is this bud (usually shaped like a tear drop and slightly lighter in color than the surrounding tissue) that will do the good work for us, so don't bruise it or abrade it. This wondrous little bud might produce either a secondary bloom spike or a plantlet, and the mechanism involved in deciding which to do and when is one I would love to understand. At any rate, when the stem is mechanically clean and debrided it must be sterilized. We soak each prop ten minutes or so in 12 1/2% clorox solution or in 3% hydrogen peroxide right out of the bottle. Put the props in a wide, shallow container, cover with sterilizing solution and lay a scrap of cloth over them. The cloth will saturate and keep the props submerged. Bill Tippit (Houston) uses an ultrasound jewelry bath to sterilize stem props. Seems to work about like our cup method, so I guess the whole thing isn't too critical. We don't bother to rinse, though one might do so with sterile water. The sterile props should be inserted straight upright in a very firm medium. It can be anything. We use Sigma fortified with banana powder. Regular seed medium. The node should be 1/4" - 3/8" above the medium surface, and the butt may have to be trimmed a bit for this. Try to leave some stem above the node as it is the reservoir for plant essentials until the new tissue begins to form. The rest is just wait, wait, wait.

In answer to Lois: "Wait" depends on the time of year. If you do a prop in early spring or summer, you'll have plants in 4 - 6 months. If you do a prop in the fall, 6 - 9 months. Just like pod maturation times. We like for the new plantlet to have two good leaves and about an inch of root before planting out. Don't plant out when the weather is real cold, however - the new plant will dehydrate. You can leave plantlets in the flask a very long time, but they really start to grow when you plant them out and that is the name of the game.

Q. Reference to removing bract--this would be the tiny, triangular "leaf" at the node?
A. Little triangular pieces that can hide a spore or two.

Q. What size plates do you use? (Lab flatware)
A. We use 125 ml bottles with a #7 one hole stopper, but anything will do. If by plates you mean lab flatware, it won't be deep enough. Props are inserted standing at attention.

In answer to an unasked question: we flask in a laminar flow hood that sees lots of hard use. I made it some time ago for about $300.00 and see no difference except price when comparing to store bought. We probably have 1 - 2% contamination, mostly due to getting rushed into sloppy technique. Remember: one man's flask is a Saint Bernard's livelihood. Hope all your props are a great success.

Ed Wright summarizes:

There are several methods of vegetative propagation: Meristem, basal plate, stem prop, chemical induction, etc. With some orchids, none of the processes are commercially significant. As a matter of fact, when you remove Cymbidium, Cattleya, Dendrobium and Phalaenopsis from the tissue culture ranks, you have little left in the "bulk" category. Due to low percentages of success, I would think Paphs would be tissue cultured sparsely, which indeed seems to be the case. What can be done and what can be done on a business basis may be two entirely different lists.

I would think the seedlings you purchased were mericlones. As discussed earlier, any vegetative division of a plant, including meristem progeny, carry the award of the parent plant. There are some paph mericlones - it's just that the procedure is anatomically more difficult with paphs and they do not produce as well. Evidently it is not felt that the procedure is economically feasible with paphs.

Catherine Cash's book, "The Slipper Orchids" (1991) looks forward to the availability of thousands of hybrids, and refers to the "limited" success of paph meristemming... which leads me to believe that it can be done and, indeed, has been done.

So, Hallie, it is possible your paphs are exactly what they are purported to be.

In making such purchases, KNOW YOUR VENDOR...mlg