laminar flow cabinet
sterilizing equipment
other equipment
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laminar flow cabinet |
sterilizing equipment |
other equipment |
SEED SOWING
Let's assume you have made a cross of two phalaenopsis and the pod is about to ripen. You have embarked on hybridization. The next step is to proceed with seed sowing as well as replating. For this you will need some sort of laminar flow cabinet or a sterilized box to reduce the risk of contamination with bacteria or spores of fungus, the latter being the biggest problem. You sterilize the laminar flow cabinet using 20% sodium-hypochlorite (bleach) and 80% sterilized water and wipe out the interior of the cabinet with this solution at least 30 minutes before use. Sterilize the rubber gloves with the same solution. You also sterilize all the tools that you might be likely to use e.g. tweezers, scalpel etc. in a flame. The flask of phytamax orchids maintenance medium (Sigma P6668), that has been prepared and sterilized before, should be wiped with 25% bleach before it is put inside the cabinet. Now we are ready to proceed.
As far as phalaenopsis are concerned, I prefer to use a green pod between 6-8 months old. I sterilize the pod for about 20 minutes in a solution of 20% calcium hypochlorite or domestic bleach with a drop or two of soft soap or Sigma Tween 20. You can also briefly flame the pod. Using a scalpel cut out the flower end of the pod and then cut along the pod, exposing the seed. With a scalpel, scrape out a portion of the seed into one or two flasks. (Just in case one gets contaminated and loses the cross). Close the flask firmly, cover them with cling film and label it. Store the flask in a warm and well-lit place, at about 70+ degrees fahrenheit. After about 2-6 weeks you may see a green shimmer on the surface of the media.
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seed pod |
seed out of pod |
magnified seed |
high magnification seed |
Once the seed pod has split, even slightly, you must assume the seed is contaminated. The fungus spores are coated with an impervious coating, which protects the seed from chemicals. You have to expose the seed to the chemicals long enough to kill any fungus and bacteria but not the seed. For this purpose I use a special vial with 10% bleach and a drop of Tween 20 and sterilize for about 20 minutes. Decant off any excess solution and add sterilized distilled water to wash the seed. Decant and scrape the seed into the mother flask. Store the flask as before in a warm well-lit place, and hopefully in a few weeks you will see some development.
REPLATING
Once the seed has germinated and the protocorms are large enough to be handled, you have to separate them into flasks containing phytamax orchid medium with banana or coconut powder as additional food and charcoal. I use ready mixed powder (Sigma media P 1056). Replating is also done in sterilized condition as described at the beginning.Do not overcrowd the flasks - put only a few plants in each flask to allow them some growing space. Otherwise you will have to replate again once they have grown bigger. During replating I add a drop (1% in sterilized pure water) of antibiotic antymycotic solution (Sigma A3303) to the media. This does help.
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germinated seed |
replated flask |
6 monts ald flask |
12 monts old flask |
DEFLASKING
When the plants have grown sufficiently in the flasks, they need to be removed and planted into so-called community pots containing a different media. Moss is usually used for phalaenopsis. During this changeover there is the danger of the plants suffering from shock. To reduce the possibility of this happening, the plants need to be acclimatized to their new environment by being washed in a solution of physan 20 first and then kept in warm, humid conditions until they have become more established. Constant monitoring is necessary during this process.
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out of flask |
comunity pots |
well established plant |
Some of the pictures used are by courtesy of Peter Fowler
