“Everyone talks about cannabinoids, but we need to bang the drum for terpenes and the other secondary metabolites that really contribute to the entourage effect,” says Dr Callie Seaman in a Monday afternoon Zoom call with Seedsman.
A leading cannabis scientist, Dr Seaman, describes herself as a “trichome lover” and says that her current research focuses on illuminating the mysteries contained within these small, hair-like structures “so that we can grow smarter”.
Terpenes Under The Microscope
Terpenes get a lot of attention these days as an increasing body of scientific evidence suggests that they may play a crucial role in enhancing the medical properties of different cultivars. However, most terpenes are only present in trace amounts in cannabis, making it difficult to produce extracts with significant quantities of these intriguing compounds.
Seaman is looking into how plants can be coaxed into increasing their terpene production to address this issue. The key, she says, lies in understanding which environmental factors trigger the synthesis of different terpenes and then enhancing these stimuli.
“Why does the plant produce these secondary metabolites? It’s all to do with stress – it’s a defence mechanism,” she explains. For instance, some terpenes act as insect repellents while others ward off larger predators like herbivorous mammals.
“Once know why a plant produces certain terpenes, the question becomes: Can we trick the plant into producing more of them?” says Seaman. “For example, if you have a strain with the genetic potential for high myrcene production, how do you use the environment to enhance that expression?”
These questions have yet to be answered, and researchers are still getting to grips with the fundamental question of what different terpenes actually do. Still, Seaman is in no doubt as to how important this line of inquiry could be for the future of cannabis. By tweaking the concentrations of these marvellous medicinal molecules, she says, it may be possible to create cultivars and extracts that are more targeted to the needs of different patients.
“It’s not just about increasing terpenes, but also reducing them,” she says. “Imagine you have a patient allergic to myrcene, but they’ve found a strain with the perfect mix of cannabinoids. Is there a way that we could reduce that plant’s myrcene production through the environment?”
The Importance Of Trichomes
Like cannabinoids, terpenes are produced and stored in the trichomes, resinous glands that coat the plant’s flowers and some of its leaves. However, rather than focusing on the contents of the trichomes themselves, growers tend to concern themselves with plant biomass – an approach that Seaman believes could be missing a trick.
“Essentially, we’re trichome farmers because all the stuff we actually want is in those trichomes,” she says. “But at the moment, when someone produces an extract, all they’re really doing is measuring the contents of their digested biomass.”
“I want to know what’s happening within the trichomes in different parts of the plant. Can we get a more specific understanding of that?” she asks.
There are six different trichome types for context, and they don’t all contain the same compounds. Nor are they all found in the same part of the plant. For instance, “the hair-like ones produce sesquiterpenes within them, while the glandular ones produce monoterpenes and cannabinoids, so you’ve got different things that are being produced in different trichomes,” explains Seaman. “We need to distinguish the different trichomes from one another and figure out what’s actually in each type of trichome.”
How This Can Be Applied Going Forward
The applications of this research could be massive for the cannabis industry. For example, suppose plant scientists can get to grips with exactly which cannabinoids. In that case, terpenes and other compounds are produced in which trichomes. Then it may be possible to create multiple extracts from the same cultivar. Before we can get to this stage, though, we need to figure out exactly which trichomes do what and enhance our understanding of where these different trichomes are most likely to appear on a plant.
“For instance, are you getting more minor cannabinoids in the trichomes towards the bottom of the plant?” asks Seaman. “If so, maybe you need to use that popcorn at the bottom to produce extracts with higher concentrations of these cannabinoids and not dilute it with all the THC that’s produced at the top of the plant.”
As a first step, Seaman is currently developing a method to measure the density of each type of trichome on a plant “and equate that to something meaningful.” One possible application of this is to help oil and extract makers to predict their yield more accurately and plan their grow operations more precisely.
“If you know how much biomass you’ve got and you multiply that by the trichome density, then you know how much oil you’re going to get from your grow before you harvest,” she says. “We’re not at that stage yet, but this research has the potential to get us there.”
Seaman is spearheading the movements toward more precise and intelligent cannabis cultivation methods by delving into the fascinating world of trichomes and terpenes. “There are lots of open questions here,” she says. “Hopefully, we’ll have some more answers in a year.”