Due to popular demand, I’ve written up a series of articles on Micropropagation of Cryptocoryne.
This is the first of a series of articles to come.
Micropropagation is a technique used to propagate plants using small fragments of the growing tip, stem, leaves, flowers and sometimes even just individual cells of a parent plant. It is often used to rapidly propagate plants for commercial use, especially in the case of plants that do not reproduce rapidly by regular means. Walk into a Garden Center today, and chances are, the plants you see there for sale were likely produced via this technique.
Micropropagation is also used for conservation of rare plant species and that’s specifically why I got interested in it.
Micropropagation differs from other propagation techniques in that it requires the plants be grown in aseptic conditions. There are for major stages of Micropropagation:
The first stage of Micropopagation, is also, in my opinion, the most difficult. This is where a segment of the plant, you’re trying to propagate is cut from the plant. This peice is referred to as the explant. Even though you cannot see this, the explant is covered in bacteria and fungus/mold spores. It is then a tricky game of trying to disinfect the plant to kill off all the surface contaminants without killing the plant itself. Once decontaminated, the segment is placed in a sterile nutrient media under sterile conditions.
The explant is placed in media that contains certain hormones, called cytokinins. These hormones exist naturally in the plant, usually the highest concentration of which is at the growing tip. Cytokinins stimulate cell division, shoot initiation/bud formation and growth of lateral buds. By adding Cytokinins to the media in certain quantities, we can promote the rapid generation of shoots from plant cells. The goal of this stage is to maximize shoot production. After a certain interval, the shoots are seperated and placed into their own containers to multiply further. One shoot turns into 5, which after the are divided, turn into 25, then 125, then 625, 2135, 15625, 78125, 390625, 1953125 – almost 2 million plants.
Often multiplication factors are increased in lab conditions due to less contamination issues and ideal conditions. Its often normal to have a 7-9 fold increase in plant mass every 6 weeks in the lab. At home, I’ve found my numbers very close to this as well.
Once enough material has been produced, plants can be induced into producing roots by placing them in a different media. This time, hormones called Auxins are used. For some plants, this step can be skipped and the plants can be placed in hormone-free media, which is usually enough to get the plant to start producing roots.
At this stage, shoots are removed from the sterile environment and placed in soil in a high humidity environment. Humidity is the gradually reduced to harden off the plant. Usually plants still have some residual hormones in them often exhibit strong lush growth.