Tissue culture is steadily gaining popularity among hobbyists and commercial growers as a means for procuring clean, high-yielding plants. Tissue culture has been the industry standard for large-scale horticulture and ornamentals for decades, but has recently branched out into other markets, including pharmaceuticals, cosmetics, and cereals.
This increase in interest is due to several factors. Tissue-cultured plants are less likely to suffer from environmental and genetic growth inhibitors due to favorable trait selection and breeding. Producing plants by tissue culture is far faster than through conventional propagation methods, resulting in higher yields in a shorter amount of time. And most importantly, the plants are virus-free, which is a huge benefit for farmers growing crops that tend to be disease-prone (eg; rice, bananas).
This all sounds great, but what actually is tissue culture? It sounds scientific, but it’s really pretty simple. Tissue culture is a form of micro-propagation, or the process of creating new plants from existing plant material. There are many different ways to go about this, but one of the most common types is meristematic tissue culture.
In this method, sections of the plant’s meristem are removed in a sterile environment (eg; under a laminar flow hood in a lab) and placed inside a growing medium, which is generally a combination of agar, basal salts, and other growth hormones. The meristem of the plant contains cells that will grow into new, genetically-identical plants.
There are four main stages to tissue culturing plants. First, initiation; the stage at which the plant cuttings are taken and placed in growing media. Second, multiplication; once a plant has grown in that media, it can be divided into more plants through the same process that occurred during initiation. After several months, these plants begin the rooting phase, which might mean transfer to a larger container or a different growing media. The fourth stage is acclimatization, where rooted plants are slowly hardened off, or brought from the sterile lab to a nursery or field.
How does hypochlorous acid fit into tissue culture? The most important factor in tissue culture success rate is the cleanliness of the work space. Tissue culture needs to be done in an aseptic (sterile) environment to ensure the plants do not bring any contaminants into the growing media, which is full of sugars that bacteria and fungus could thrive in. This means everything, from the lab technician to the growing media itself needs to be first cleaned, and then sterilized.
As a reminder, hypochlorous acid is not an acceptable method for sterilization--this should occur in an autoclave. However, hypochlorous acid can be used to keep sterilized items clean, and as a pre-sterilization cleaning method. Use hypochlorous acid at 500 ppm for soaking all media vessels, media prep equipment, and lab tools after washing and before autoclave sterilization. Hypochlorous can also be added to laundry at 500 ppm for disinfecting lab coats and as a boot wash before entering the lab.
Another way that hypochlorous acid can be used in tissue culture is during the sanitization of plant material. During plant intake, the plant cuttings must be thoroughly surface sanitized to kill any fungus or bacteria that’s living on the leaves and stems of the plant. While bleach is a common solution used for this step, hypochlorous acid can also be used. Simply add 200 ppm to a sterilized vessel with the plant material and shake for at least 15 seconds.
You may not have heard of tissue culture before, or even hypochlorous acid, but they both have one thing in common--they’re going to be a prominent part of our future. This is evidenced by the growing number of facilities adopting tissue culture and the companies now incorporating hypochlorous acid into their protocols.
As an example: Athena recently released a “DIY Tissue Culture Kit” that includes their own bottled hypochlorous acid product, Cleanse, as part of the plant sanitation protocols. Since Athena is an industry leader in hydroponic nutrients, we expect that many other companies will follow and offer something similar. This is why it is important to have your own Hypo machine, so you can save money and make as much hypochlorous as you need.
Hasnain A, Naqvi SAH, Ayesha SI, Khalid F, Ellahi M, Iqbal S, Hassan MZ, Abbas A, Adamski R, Markowska D, Baazeem A, Mustafa G, Moustafa M, Hasan ME, Abdelhamid MMA. Plants in vitro propagation with its applications in food, pharmaceuticals and cosmetic industries; current scenario and future approaches. Front Plant Sci. 2022 Oct 13;13:1009395. doi: 10.3389/fpls.2022.1009395. Erratum in: Front Plant Sci. 2023 Apr 17;14:1197747. PMID: 36311115; PMCID: PMC9606719.
Bonnart RM, Chen KY, Volk GM. 2022. Plant Tissue Culture Media Preparation. In: Volk GM (Eds.) Training in Plant Genetic Resources: Cryopreservation of Clonal Propagules. Fort Collins, Colorado: Colorado State University. Date accessed. Available from https://colostate.pressbooks.pub/clonalcryopreservation/chapter/media/