Cannabis is a multipurpose crop with diverse values and applications in a wide range of areas, including domestic, medicinal, and recreational areas. The plants are often grown using the conventional approach, in which cuttings are taken from a mother plant to create genetically similar plants.
However, despite producing true-to-type plants, the technique requires a huge area and is expensive in long run. Also, it has been observed that the plants become less vigorous over time and the mother plants become susceptible to disease and pests. Furthermore, cuttings may harbor diseases and act as primary inoculum in production spaces.
Thus, tissue culture or in vitro propagation offers an effective approach to fighting and overcoming these challenges. It’s a promising solution to the mass production of plants and germplasm conservation. Moreover, it’s a quite popular technique in horticulture and agriculture space for its advantage over producing disease-free plants at a commercial scale in a short time.
Though it might sound like a new and recent technique, the concept of tissue culture goes back to 1902. It was first practiced on orchids and since then its benefits over the conventional approaches have attracted the attention of growers, plant enthusiasts, scientists, and plant businesses for a range of other applications.
So far today, the technique has been practiced on many economical crops and plants, such as sugarcane, potato, ornamentals, strawberry, sweet potato, roses, orchids, fruits, rice, banana, and many other horticulture crops for disease eradication or mass production.
Do you know that tissue culture is widely exploited in ornamental businesses to create beautiful hybrids of flowering or indoor plants? It's done to obtain plants with different structures, variegated leaves, different textures, flowers of a spectrum of colors, and introduce many other selected features.
Thus, considering the advantages, tissue culture seems to be a promising propagation technique for the mass production of plants and the elimination of diseases and pests. Furthermore, it can also provide an effective solution for long-term storage of the crop, maintaining genetic integrity, and scale-up the production of genetically identical plants.
In this article, we will learn about the tissue culture of cannabis and the factors that can impact its production in the in vitro space.
Tissue Culture of Cannabis
Cannabis micropropagation and conventional approach have become a common practice in the Cannabis propagation system. However, some other techniques are also being tried by scientists for the growth of such plants. It includes leaf-derived callus, axillary nodes in calcium alginate beads, and temporary immersion bioreactor systems.
Thus, considering the advantages of the Cannabis tissue culture over the traditional approach is the reason that the technique is slowly seeping into the Cannabis industry. It’s expected to become a more common choice among Cannabis growers for genetic preservation and clonal propagation of Cannabis in near future.
Factors Affecting Micropropagation of Cannabis
Many factors play their roles in obtaining high yield and supreme quality of plants and crops in tissue culture. The knowledge of these factors makes growers more aware of their culture system and understand if there’s anything wrong, what that might be.
The understanding of these factors allows culturists to overcome many challenges in tissue culture systems, such as lower yield, contamination, infection, or unhealthy plants.
1. Plant material selection
Selecting a healthy plant material is the first step to tissue culture. Based on their purposes growers choose their explant source. For example, to eliminate viruses and infections, they prefer meristematic tissues.
So far, previous studies have shown the micropropagation of Cannabis using explants like axillary buds, shoot tips, and cotyledons through direct organogenesis. The explants’ age, source, place in the plant, and size are other factors that determine the response of the plant in tissue culture.
Some studies have observed that petioles, internodes, cotyledons, axillary buds, and young leaves are better responsive toward callus production. However, the callus obtained using cotyledons had the highest regeneration efficiency.
2. Surface sterilization
Another step to tissue culture is surface sterilization of the collected plants. It’s essential to ensure that you are using the right chemicals, in the right concentration, and giving them the right exposure time. It’s mainly to obtain viable and healthy tissues free of germs.
If you expose the explant to too much concentration of the chemical or gave it too much exposure, it might cause damage to the tissues and they may either die in the process. Similarly, exposing the plants for a lesser time than optimum and sterilizing them at lower concentrations might not completely eradicate germs, which may cause contamination in your cultures.
Generally, distilled water, ethanol, sodium hypochlorite, mercuric chloride, Tween 20, and calcium hypochlorite are used in different concentrations and combinations for the surface sterilization of Cannabis. You must have a proper surface sterilization approach to obtain a good yield of Cannabis in tissue culture.
3. Culture Media
Tissue culture media is composed of macro and micronutrients and vitamins that are required for the growth and development of plants under in vitro conditions. Thus, they are mainly curated based on the needs of the plants.
MS (Murashige and Skoog) media is the most commonly used tissue culture media Cannabis growers used in their tissue culture system. However, some scientists have also reported the use of modified MS media and Daria ind medium for Cannabis seed germination. Inaccurate culture media, containing nutrients and vitamins than what is required by plants, may lead to no explant growth, weak plants, or explants death.
4. Culture conditions
Every plant has its own environmental needs. Each of the species prefers different temperatures, pH, and humidity for their proper growth and development. And, in tissue culture, scientists mimic the exact environmental condition that is favorable for plant growth in an outside environment.
For example, in vitro Cannabis cultures require 22-26 ºC with a 16-h photoperiod. But, if one needs to induce seed germination or callus formation, the process is required to be carried out in complete darkness. Thus, based on your goal and the explanation you use, the culture conditions differ a bit as well.
If you don’t provide the right temperature, pH, and humidity conditions for the cultures to reason in vitro, they won’t show any response. It means spoilage of the effort, time, and money that you have put into the process.
5. Plant Growth Regulators
Plant growth regulators, also known as plant hormones, are essential for the organ development and growth of plants in vitro conditions. In the natural environment, the plants produce these hormones on their own that facilitate their growth. However, in artificial conditions, they require the addition of these hormones from outside to support their development.
The two hormones extensively exploited in tissue culture space include auxin and cytokines. And, different forms of these hormones are commercially available for their use in the tissue culture procedure. Thus, while performing the Cannabis tissue culture, it’s essential to ask yourself what hormones you should use and in what concentration to obtain a better response from your in-vitro cultures.
For example, some studies have reported the use of 0.5 µM TDZ in MS media for nodal explants, while some studies have shown that 0.2 mg/L TDZ and 0.1 mg/L NAA work best with the shoot tip explant.
6. Acclimation Factors
Acclimation is the last and one of the most crucial steps of tissue culture. Any mistake at this stage can spoil you whole investment you put in your Cannabis business. Adaptation to environmental changes through efficient acclimatization provides minimal damage to plants before being transferred to the soil.
It’s essential to use the right conditions, which means exposure to the right temperature, pH, water, humidity, and light, for the healthy development of plants and to minimize pathogen and pests attack.
Some scientists use peat and perlite for Cannabis acclimation, while some others use coco natural growth medium for the increased survival rate of Cannabis plants. You must ensure that all the factors are acting in harmony for the proper growth and development of cultures in an artificial environment.
Plant Cell Technology Presents "Cannabis Tissue Culture Masterclass" To Solve All Your Cannabis Micropropagation Issues
Now, you might have several questions regarding the factors:
- How to know which explant is perfect and how to choose them? What characteristic should you observe?
- How can one differentiate between low-grade and high-grade chemicals?
- How to know which surface sterilization technique is suitable for your Cannabis plant? And, how to learn about their effect on your chosen explant?
- How to prepare the right tissue culture media?
- How to know among all the available hormones, which will best suit your Cannabis plant and in what concentration?
- How should you transition your plants from the lab to the greenhouse and acclimate them? What practices or steps to follow?
You can get answers to all these questions and more in our coming Cannabis Tissue Culture Master Class.
The Cannabis Tissue Culture Seminar educates you and provides you with all the resources you need to get started in your journey to produce disease-free Cannabis, meeting all regulatory complaints.
You can join the basic courses, where you will learn more about basic Cannabis tissue culture like media preparation, meristem dissection, and cannabis micropropagation, or even join the expert courses, where we will dive further into pathogen remediation by media amendments, gender screening, long-term storage solutions, procedures, protocols, and solutions to prevent contamination from your lab and increase Cannabis yield!
So whether you are a beginner or an expert, the seminar is FOR YOU!
Additionally, you will get to network with tissue culturists from around the world and will receive a certificate to show you are now the expert!
Thousands of cannabis growers have already joined and booked their tickets to level up their Cannabis propagation business.
Don’t stay behind, book your tickets now!