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Writer's pictureCarol Stiff

Cannabis Plant Tissue Culture: Is It For You?

I have been involved in plant tissue culture research and teaching since the ’70s and started my own small company in 1998 (Kitchen Culture Kits Inc.), which is devoted to teaching plant tissue culture to hobbyists, students, and all plant lovers interested in new techniques using economical supplies, most of which can be found in the kitchen. I got involved with cannabis tissue culture when we moved to Clark County in Washington. My goal with cannabis TC was to help medical users grow enough plants to meet their needs.


What is the definition of a cannabis plant in your state? Why is this important?


Think about this for a few minutes while you read about plant tissue culture below.


What is plant tissue culture?


Plant tissue culture (micropropagation, cloning, in vitro culture) is a method of plant propagation that involves growing pieces of plants (shoot tip, node, leaves, etc.) in a sterile environment and producing numerous new plants ("plantlets") year-round using supplies from your kitchen or classroom. In the past, this was restricted to university and industry laboratories but since 1998 we have been teaching people how to do this in their kitchens and classrooms using inexpensive supplies. See www.kitchenculturekit.com and www.hometissueculturegroup.org for more details, and for a free workshop handout, email carolstiff@kitchenculturekit.com I can also connect you with a source of free supplies that will help you get started.


Can cannabis be tissue cultured?


YES, but be cautious. Plant tissue culture techniques do not work for all plants, and media and environmental requirements may differ even between strains in the same genus. Be cautious when experimenting with new strains including the same strain grown by different growers or in different environmental conditions. You may want to stick with conventional cloning methods.


Cannabis is cultured like tomato or potato culture (as shown above): stems are sectioned into node pieces, each containing 1-2 axillary buds, disinfected with dilute bleach, and cultured in a sterile environment containing fertilizer constituents, a carbon source (usually sucrose), vitamins, hormones.


Do not put all your plants into tissue culture or you could lose your germplasm. Preliminary testing is necessary to determine the optimum requirements.


Some cannabis strains are highly susceptible to “hyperhydricity” (also referred to as “vitrification”) where plants appear to be wet, waterlogged, glassy, translucent, with swollen, turgid, brittle leaves (photos above). Other symptoms can be poorly developed vascular bundles, abnormal wax quality, abnormal functioning stomata.


Causes of hyperhydricity are not fully understood but it can be reduced by decreasing humidity in the culture vessel, increasing the concentration of agar in the medium, increasing concentration of sucrose, decreasing ammonium ions in the medium, reducing or eliminating growth regulators, and others. Those who are successful tend to not share their secrets and many professional publications do not acknowledge the problem.



How do I get supplies?


Kitchen Culture Kits has a list of vendors. Some companies sell specific media for hemp: https://phytotechlab.com/catalogsearch/result/?q=hemp and https://microclone.com/shop

KCK also sells a kit but includes basic MS medium with a selection of 5 hormones so you can experiment with your particular strain. Remember, all strains do not respond the same.


Does anyone teach workshops, or can you recommend YouTube and other video sources?


Bill Graham of Microclone Inc. probably has the best selection of videos as well as considerable experience: https://microclone.com/videos plus he teaches cannabis-specific workshops. KCK has taught workshops around the US for 23 years but just the basics. As a medical cardholder who promised the family, she would stay legal, I have only had a limited supply of plant material to work with. Plant Cell Technology has videos, supplies, and specifics on cannabis culture.


Does anyone in the cannabis industry use tissue culture to propagate plants?


Many have boasted that they use plant tissue culture, but few really show their laboratories, and hopefully in the future I will be able to visit some labs and bring you up to date. One lab has an extensive website showing thousands of plants in culture, and I hope to visit it this summer.


Back to what is the definition of a cannabis plant. According to Washington State Legislature RCW 69.51A.010, which is in effect until July 1, 2022: (17) "Plant" means a marijuana plant having at least three distinguishable and distinct leaves, each leaf being at least three centimeters in diameter, and a readily observable root formation consisting of at least two separate and distinct roots, each being at least two centimeters in length. Multiple stalks emanating from the same root ball or root system is considered part of the same single plant.” Remember that 1-inch equals 2.54 centimeters, thus 3 centimeters equals 1.1811 inches. Plants in tissue culture tend to have small leaves and few roots thus they are not legally a plant.


Those of us with medical cards can grow as much as 15 plants, thus if you could develop a successful tissue culture system, you could maintain many backup cultures but continue to grow your 15 or fewer plants. Unfortunately, cannabis tissue culture is not easy so be cautious before heading down this path. Experiment with other plants first (potato, tomato) and get your technique perfected. Read as much as you can and attempt to talk to others who have been successful.


For more information, free references, a free workshop handout, and a link to a free video contact me at kck@turbonet.com.


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