Meristem propagation - definition + instructions to make yourself


The Content Of The Article:

DNA - DNA double helix

The Meristemvermehrung is still a fairly new way of plant propagation. But it is already widely used. First, because some plants can only be multiplied free of viruses and bacteria in this way. On the other hand, because this method can be used to grow numerous and genetically identical seedlings from a single mother plant. However, due to the necessary equipment, precautions and the required knowledge, the procedure itself is difficult to carry out. Anyone who has patience and a willingness to experiment, but can still record amazing successes.

definition

Meristem propagation is also referred to as in vitro propagation. "In vitro" in Latin means "in the glass". What is meant here is an increase in Petri dish or test tube. Hobby gardeners, who previously dealt with seeds, cuttings and the division of roots, that should surprise. In fact, however, the meristem propagation is already being operated on a large scale. The propagation of the plants takes place from individual cell groups and under sterile conditions.
The cells are removed from the plant, placed on a nutrient medium and treated here with nutrients and phytohormones until roots and shoots form. They are then placed in substrate and cultivated according to the requirements of the particular crop. Roughly speaking and greatly simplified, it is a kind of cuttings propagation on a microscopic scale and under sterile conditions.

advantages

As already mentioned, the meristem propagation offers two decisive advantages. Above all, the economic advantage is hard to miss: From a single mother plant significantly more offspring can be drawn than from cuttings or seeds. As a starting material for a daughter plant finally only a few cells are required. In addition, some plants can hardly be multiplied by other means. Possible reasons for this are that the division, formation of cuttings or the cultivation of the seeds is extremely complicated and takes a lot of time.
In addition, bacteria, fungi and viruses as well as other phytopathogens make propagation through cuttings and culture of some plants more difficult. For this reason, for example, strawberries, raspberries and kiwi are now mainly generated by the meristem propagation. Young plants obtained in this way are free of pathogens as they are grown under sterile conditions. The risk of ill offspring is also reduced.

The meristem

The starting material for the meristem propagation is the meristem. This is the educational tissue of the plant. This type of tissue is still undifferentiated. They can therefore develop into roots, fruits or leaves and at least theoretically share them indefinitely. The best conditions, therefore, to be used for the propagation and to create numerous plants from small amounts of cells.
These plant stem cells are located in the extreme ends of the root tips and shoot tips. In addition, they have thin cell walls with a very low cellulose content. So they differ in terms of the cell walls of the surrounding cells. Of course, this is only visible under the microscope.

Sterile conditions

The upper sprout tips are generally suitable as meristems for in vitro propagation, since they are usually even free from viruses even in the case of an existing viral disease. So that the pathogens can not subsequently pass to the cells or plant parts, sterile conditions in the meristem propagation are essential. The seed tanks must therefore be sterile and also be closed. Proven here for the initial stages Petri dishes with lid. Later, higher glasses are used. The professional implementation of meristem propagation also creates a special atmosphere that is continuously regulated. This requires, among other things, a sterile workbench or safety workbench.

Disinfect

Although sterile workbenches and vessels are needed for the proliferation of meristem, they alone are not enough. With the Meristemzellen germs can be registered. It does not matter whether they were already present on the plant or were added to the nutrient medium on the way from the plant for application. In turn, bacteria, fungi and viruses can significantly reduce the success rate. It is therefore necessary to additionally sanitize the cell clusters after removal from the plant to kill bacteria and fungal spores.
According to various sources, the following three means are used in particular:
  • sodium hypochlorite
  • hydrogen peroxide
  • Mercuric chloride

Avocado root

Sodium hypochlorite and hydrogen peroxide are each available at the pharmacy. The use of mercury-II chloride for the disinfection of plants and seeds is prohibited, at least in the private sector.However, even with the available substances must be paid very carefully to the concentration.

Sodium hypochlorite for disinfection

In professional meristem propagation, sodium hypochlorite is used to disinfect cell clusters. The chemical substance is also known as sodium hypochlorite and is often referred to as "active chlorine" in detergents. The aggressive agent should therefore not be used undiluted in plant cells.
Here are usual concentrations of 5 to 25 percent with a contact time of 5 to 30 minutes. Sodium hypochlorite should therefore only be used in a corresponding dilution. After disinfection, the cells are also rinsed several times with distilled and sterile water.

hydrogen peroxide

For rinsing plants and plant cells, some sources propose a solution with 0.15 parts per thousand or 0.015 percent hydrogen peroxide. For household purposes, a 3 percent hydrogen peroxide solution is available in pharmacies. In order to align them to a hydrogen peroxide content of 0.015 percent, the following calculation is required: Percentage of the starting solution - desired percentage of the disinfecting solution = difference and thus water content in the mixing ratio
For the 3 percent solution, the bill is: 3 - 0,015 = 2,985
This means that 0.015 parts of the 3% solution must be added to 2.985 parts of sterile, distilled water. More illustrative and more practical for the increase in meristem are 1.5 milliliters of the solution to 29.85 water.

Nutrient medium and nutrients

At this point it gets complicated. Although there are nutrients that must be contained in the nutrient medium in each case - but the respective concentration depends on the respective plant species. The basis may be a mixture of agar as gelling agent and sucrose as nutrient solution. The solution should contain a sucrose content of 20 to 30 grams per liter of water. Agar is used as needed.

macronutrients

The important macronutrients for meristem propagation are:
  • nitrogen
  • phosphorus
  • potassium
  • calcium
  • magnesium
  • sulfur
The concentrations of these substances, however, are very species-dependent. Even in the scientific sources for this, there are significant differences in the information, for example, are alone in potassium between 0.95 and 1.9 grams per liter.
Tip: If you want to start experiments yourself, you have to experiment carefully. An orientation here can be the content of the individual macronutrients in special fertilizers for this plant species.

micronutrients

Important micronutrients for plants in general and meristem reproduction in particular are:
  • iron
  • manganese
  • zinc
  • boron
  • copper
  • molybdenum
If they are completely absent or in too low a concentration, deficiency symptoms appear. Iodine and cobalt should also have an impact on growth. Scientifically proven this is not yet. Again, it is true that the amounts vary greatly and are dependent on the type of crop. Again, special fertilizers can be used for the respective plant for orientation.

Vitamins and amino acids

In meristem proliferation, B vitamins are crucial.
Here are:
  • Biotin - Vitamin B7
  • Folic acid - vitamin B9 or vitamin B11
  • Nicotinic acid - Vitamin B3
  • Pyridoxine - Vitamin B6
  • Thiamine - Vitamin B1
Although plants can produce them themselves, they are still added in some common nutrient media to promote growth and increase the rate of success.

phytohormones

Since the meristem is still undifferentiated cells, they need corresponding impulses. Otherwise they would not develop in roots, sprouts and leaves. These impulses are provided by the four phytohormones:
  • auxins
  • cytokinins
  • gibberellins
  • abscisic acid
In some finished nutrient media, these as well as the macro and micronutrients are already included. For a self-made mixture, they must be added. This in turn is a challenge, as the amount and the relationship to each other must be tested.

Grading

Sweet potato plant with roots

The cells divide successfully in the meristem propagation and provide the phytohormones for the desired development of the individual plant organs, grow young plants. These are genetically identical to the mother plant, in fact they are clones. Despite this success, there may still be problems along the way. As a rule, these are triggered by registered germs, which can thrive on the nutrient medium just as well as the plant cells themselves. Therefore, the bonitizing is very important. If the nutrient medium is turbidities, deposits or discolorations, the specimen should be sorted out. The control and the removal are called crediting.

plant out

Have the young plants reached a height of about five centimeters, are strong and healthy, they can be planted in a corresponding substrate. From this point on they can be cultivated as required by the particular plant species.

The alternative to own meristem propagation

Own attempts of Meristemvermehrung are due to the requirements and the necessary equipment actually only useful if more than one mother plant is to be propagated. Moreover, it is not an easy task. Already the preparation of a suitable and coordinated nutrient medium and keeping the cells sterile is difficult to achieve in a private household. Nutrient gels can also be bought ready. For example, the PhytoTechnology Larboratories.
Who wants to save the effort and expenses, including for the sterile workbench, can also increase their own plants. This is offered, for example, by the In Vitro Plant Service in Quedlinburg.
Conclusion
Meristem propagation is a good way to grow a large number of plants from a single mother plant and often the only way to reach healthy offspring, especially in the case of virus-susceptible plants. With the right equipment, it is also feasible by laymen. From the production of the meristem cells under the microscope over the production of a suitable nutrient medium to Bonitieren, this variant of the propagation is also a challenge.

Video Board: B26.1.1 Reproductive health (Hindi).

© 2019 EN.Garden-Landscape.com. All Rights Reserved. When Copying Materials - The Reverse Link Is Required | Site Map