By Dr. Matthew Lisy, UConn Adjunct Faculty
UConn Home & Garden Education Center
Ever wonder how new varieties of houseplants are produced so quickly? Tissue Culture is most likely responsible for this. Many people think this is new technology, but it has been donesuccessfully since the 1950s. Recently, I was surprised to see tissue cultured houseplants available in a big box pet store.
If plant breeders had to wait for a plant to clone itself the natural way, the supply of rare houseplants would be extremely limited. This would cause the consumer to have to pay an exorbitant price, and the demand would far exceed the supply. Tissue culture allows for a short cut.
Plant cells exhibit totipotency, or the ability to regrow a whole new plant from a single cell. While our cells differentiate and stay that way, plant cells can dedifferentiate and then grow into a whole new plant. This is why plant propagators can take a small piece of a plant leaf, and grow it into a whole new plant with roots, stems, leaves, and any other tissues the plant needs.
The plants I found were in a very small package almost the size of a cell phone. There was some nutrient agar in the bottom, and a bunch of little, tiny plants. Some of the plant packets had rotting plants, but I selected two nice and green healthy ones – Philodendron sp. ‘Pink Princess,’ and Philodendron sp. ‘White Knight.’ In order for tissue culture to be successful, the cutting used needs to be completely sterilized, or fungus and bacteria will ruin the culture. The agar provides all the moisture and nutrients the growing plants need. Although operations can vary, once baby plantlets are observed, they are generally moved to a larger growing medium under sterile conditions. When big enough to handle, the plants are potted up and grown on like any other plant would be. The plants I bought were extremely tiny, with leaves, stems, and very small roots. I left them in the bags they came in for a few weeks, and put them under LED grow lightsto increase their size.
Once the plants looked big enough to handle, I placed them into soilless growing medium. It’s a good idea to keep them moist under a plant dome to avoid dehydration. I would regularly mist the enclosure to keep the humidity high. The plants have done extremely well. When I started to notice some fungus on the surface of my soil, I quickly increased the air flow which dried it upimmediately. I still have the plants in the dome, but with all the vents wide open. The plants have grown much bigger and are looking great. Once the plants get to the point where they could use their own pot, I will separate the biggest ones out and leave the little ones to grow on for a while. Once they start growing after transplanting, I fertilized every time I watered.
The disadvantage of buying tissue cultured plants when they are young is that it takes a long time for them to reach a respectable size. It is also difficult to see what they actually look like and can be difficult to separate the baby plants. There are, however, many advantages. Plants are very cheap, numerous, and free from pests and diseases. The grower also gets a special sense of accomplishment when the plants are raised from little plantlets to full grown adults!
For your gardening questions, feel free to contact us, toll-free, at the UConn Home & Garden Education Center at (877) 486-6271, visit our website at www.ladybug.uconn.edu or contact your local Cooperative Extension center.