Hosta is a genus of plants known as Hostas. It is an East Asian plant cultivated widely in the west because of its shade-tolerant foliage and loose clusters of tubular mauve or white flowers.
Tissue Culture Hosta:
For commercial purposes, some hostas are produced in a high-tech process, know as tissue culture, that is why it is called “tissue culture hosta”.
In this process, very small pieces of plant are taken from the mother plant,which are then processed in a highly sterile environment. The pieces of plant are placed in test tubes, with specific type of substrate and are continually divided as new cells are formed. Eventually, from a very small piece of plant, thousands of exact duplicates (clones are produced). This is the most expensive process, because each step must be performed in disease free and sterile environment. If there is contamination by fungal spores from outside, everything may be lost to mold or rot rapidly.
During this process, spontaneous variation from the original plant(Sport) may occur. There is higherprobability of Sport because it involves the use of plant hormones and chemicals in theAuger. This can result in a new variety or a plant that can be discarded, because it is not same as the mother plant.
Revolutionary changes in the world of Hostas:
In past few decades, there have been revolutionary changes in the world of hostas, that is TC (tissue culture) for the micropropagation of hostas. It is a new techniqueof creating new plants from cuttings.
Difference between Regular Cutting and TC:
The difference between them is that TC requires highly sterile environmental conditions. It isan in-vitro process which means that it takes place in glass. It is very laborious, equipment sensitive and therefore expensive technique.
The general process consist of four stages, however some of the specifics vary from lab to lab.
The first three stages are completed in glass under highly sterile environmental conditions. There must be highly controlledtemperature, light, chemicals and other conditions to bring successful outcomes.
The fourth step take place outside the lab and involves growing plants in regular greenhouse conditionsthe same as any other seedling or cutting.
- Initiation :
A small bud from the crown of plant i.e. explant. The bud is then peeled back delicately to its smallest point and is cleansed and disinfected thoroughly. All cutting must be done with sterilized equipment. A mixture of nutrients of plant, plant hormones and agar is prepared under sterile conditions and poured into a test tube. The pieces of explant is then placed carefully in the bottom of tube nestled on the top of agar mixture.
The test tubes are then placed in a racks maintaining sterile environment, with artificial light, controlled temperature and humidity control.
At this point, plantlets do not have roots, so they depends entirely on sugar in agar for energy, instead of photosynthesis.
- Multiplication :
As the time goes on, the plant tissue in the test tube grows, buds multiply and it needs more room. So, the periodically the plant tissue is taken out of test tube, cut into smaller pieces and distributed into more test-tubes. This may be done every 4-6 weeks under strict sterile conditions. It is estimated that each bud will produce as many new buds in a year as it would be in 10 years in a garden. These plants multiply rapidly in TC.
Two plant hormones are used in TC.
- Cytokinin which encouragesbud formation.
- Auxin that encourages root growth.
- Rooting New Plants:
After the completion of several rounds of multiplication, the plants are then switched over to an agar mixture, in which levels Auxin are higher than that of Cytokinin. This will assist in triggering root formation in new plants.
- Growing the Plants outside the lab in Greenhouse :
Once the plantlets have formed root masses, they will be divided once again and each one of them will be planting in container of Potting media. Afterthis, they will placed in a greenhouse for growing onto a sealable size at wholesale nursery. This is known as ex-vitro (not in glass) process.
General Reasons of Using TC:
- Clone Production:
TC is uses to maintain the exact characteristics of the original plant in new plants, because new plants created in this way are the exact replicas of original ecplant.
- Plants difficult to Propagate?
The plants who do not propagate easily propagate through standard cuttings, seeding, layering etc., TC is last resort option for them.
- Fast Production :
Plants produced through TC can be multiplied rapidly, and made available quickly for sale.
- Disease Free Plants:
Because highly sterile environmental conditions are maintained, therefore, plants produces are certified disease free.
Hostas tend to be frequently mutate or sport on their own as compared to other plant genra. In a population of ten thousand hosta, there may occur dozen of sports.
TC has become a source of new hosta cultivars in recent years.
If you are based in London, then we suggest you contact your friends at LDN Gardeners so they can further help you if you cannot do this yourself.