Cannabis sativa has become one of the most closely watched crops in plant science, and a new open-access review published in Discover Plants pulls together what is known about how environmental stress governs the plant’s most valuable chemistry. The review, authored by Sanjeev Kumar, Ruchika Devi, Garima Vashisth, Ibajanai Kurbah, Rupam Nehta, Y. P. Sharma and Nitesh Kumar, synthesizes current knowledge on the physiological, molecular and metabolic mechanisms that link drought, salinity, temperature extremes, nutrient imbalance, light stress and pathogen pressure to the biosynthesis of cannabinoids and terpenes. Its central message is that the chemical profile of this plant is not fixed by genetics alone but is continuously reshaped by the environment the plant experiences.
The authors frame Cannabis sativa as an unusually good model organism for studying stress-induced metabolic responses. The plant produces more than 550 different chemicals, including the phytocannabinoids cannabigerolic acid (CBGA), cannabidiolic acid (CBDA), tetrahydrocannabinolic acid (THCA) and cannabichromenic acid (CBCA), which decarboxylate over time and with heat into the neutral compounds CBG, CBD, Δ9-THC and cannabichromene. Alongside these sit terpenes such as the monoterpenoids α-pinene, β-pinene, limonene and myrcene. Because cannabinoid and terpene accumulation occurs predominantly in the glandular trichomes of female flowers and adjacent sugar leaves, intensifying during floral development as trichome density increases, the timing and severity of stress during flowering can have outsized effects on the final harvest.
At the biochemical level, the review describes cannabinoid biosynthesis as the product of two converging routes. The polyketide pathway, through the coordinated action of tetraketide synthase and olivetolic acid cyclase, generates olivetolic acid, the cannabinoid backbone. In parallel, the plastidial MEP pathway produces geranyl diphosphate (GPP), a shared isoprenoid precursor for both monoterpenes and cannabinoids, while the cytosolic mevalonate pathway supplies dimethylallyl diphosphate for sesquiterpene production. GPP acts as a central metabolic junction: plastid-localized prenyltransferases PT1 and PT4 condense olivetolic acid with GPP to form CBGA, the universal precursor of all major cannabinoids. This convergence point is described as a major control point regulating carbon flux into cannabinoid biosynthesis, with enzyme activity from DXS, DXR, HMGS and HMGR in the MEP and MVA pathways shaping precursor supply.
The most quantitatively detailed finding concerns water deficit. According to the review, moderate drought stress, defined as maintaining soil at 60 to 70 percent of field capacity, stimulates stress-responsive metabolic pathways, increases glandular trichome density and upregulates key CBD biosynthetic genes. Under these conditions CBD content increased by roughly 12 to 15 percent, while THC rose by approximately 8 to 20 percent, or up to 25 percent depending on genotype. The response is sharply dose dependent: severe drought below 40 percent field capacity reduced metabolic activity and substantially decreased total cannabinoid accumulation. Terpenes respond too, with moderate water deficit raising accumulation of the monoterpenes myrcene, limonene and pinene and the sesquiterpenes β-caryophyllene and α-humulene, compounds that determine aroma and flavour.
The physiological chain connecting drought to chemistry runs through photosynthesis. Stomatal closure under water deficit restricts carbon dioxide diffusion and lowers carbon assimilation, leaving the light reactions producing more NADPH and ATP than the Calvin cycle can consume. The review argues that this excess reducing power may be diverted into secondary metabolism, with surplus NADPH associated with increased THCA production, and that excess energy is dissipated through non-photochemical quenching and photorespiration to avoid reactive oxygen species formation. Maintaining dry biomass under drought appears to be a primary factor in sustaining high secondary metabolite production throughout the stress period.
Light, particularly ultraviolet radiation, emerges as another key regulator. Cannabis shows unusually high tolerance to excessive light, though photosynthesis declines at supra-optimal temperatures above 30 degrees Celsius. Field studies cited in the review found higher THCA levels in plants grown at higher elevations, where solar UV radiation is stronger, and subsequent controlled-environment experiments confirmed that UV exposure induces THCA production. The authors interpret this as evidence that cannabinoids serve an ecological function, shielding female reproductive organs from elevated UV, and note that UV also regulates flowering time, height and lifespan without pollination.
Temperature and nutrients add further layers of complexity. Systematic studies of three drug-type and four fibre-type cannabis varieties grown between 20 and 40 degrees Celsius showed significant differences in thermal tolerance ranges, with varieties from warmer climates achieving maximum photosynthesis near 35 degrees, pointing to genotype-by-environment interactions. On nutrition, the review reports that high-THC medical cannabis has an optimal nitrogen concentration around 160 milligrams per litre, with levels below 80 milligrams per litre impairing photosynthesis and growth, while phosphorus recommendations of roughly 30 milligrams per litre during the vegetative stage show little benefit beyond 30 to 90 milligrams per litre. Low potassium, around 0.2 millimoles per litre, reduced photosynthesis in both stress-sensitive and stress-resilient hemp, though resilient strains compensated with higher chlorophyll, antioxidant expression and stress-hormone enzyme activity.
Hormonal signalling offers a route to deliberate manipulation. The review highlights salicylic acid, which studies link to increased size and density of glandular trichomes in cannabis, jasmonic acid, whose activation increased cannabinoid content in flowering plants, and abscisic acid and gamma-aminobutyric acid as regulators of stress adaptation and secondary metabolism. Membrane permeability modification, using agents such as dimethyl sulfoxide, surfactants, chitosan, pulsed electric fields and ultrasound, is described as the most commonly investigated physical and chemical approach to enhancing metabolite accumulation and release.
The review also surveys less settled territory. Polyploidization studies show substantial changes in plant morphology and vigor, but published results conflict on whether chromosome doubling raises THC and CBD levels, with some studies reporting positive effects and others no significant change. On the medical side, the authors summarize evidence that cannabinoids such as CBD and Δ9-THC exhibit antioxidant and anti-inflammatory properties, with CB2 receptor signalling suppressing ROS-producing enzymes and activating the Nrf2-regulated antioxidant cascade, though they note that cannabinoids’ role in plant defence against fungal and bacterial pathogens still requires clarification.
The authors close by identifying the field’s major gaps: quantitative relationships between stress intensity, duration, developmental stage and metabolite accumulation remain poorly defined, terpene synthase regulation and post-transcriptional control are underexplored, and combined stresses such as drought with heat or temperature with UV-B, along with high-altitude environments, need multi-omics investigation. They argue that future progress will require moving beyond single-factor experiments toward integrated physiological, metabolic-flux and machine-learning-assisted approaches, combined with optimized tissue-culture and transformation systems, to develop climate-resilient cultivars with stable and predictable phytochemical profiles.
Subject of Research: Stress regulation of cannabinoid and terpene biosynthesis in Cannabis sativa
Article Title: Stress biology of Cannabis sativa regulating cannabinoid and terpene biosynthesis at physiological, molecular and metabolic levels
Article References: Kumar, S., Devi, R., Vashisth, G., Kurbah, I., Nehta, R., Sharma, Y. P., & Kumar, N. (2026). Stress biology of Cannabis sativa regulating cannabinoid and terpene biosynthesis at physiological, molecular and metabolic levels. Discover Plants, 3(1), Article 507. https://doi.org/10.1007/s44372-026-00973-7
Image Credits: AI Generated
DOI: 10.1007/s44372-026-00973-7
Keywords: Cannabis sativa, cannabinoids, terpenes, drought stress, glandular trichomes, biosynthesis, MEP pathway, salicylic acid, UV radiation, polyploidization, secondary metabolites, plant stress
News Source: Bethany Barker. (October 29, 2026). How Stress Shapes Cannabis Chemistry: A Review Maps the Physiology Behind Cannabinoids and Terpenes. Scienmag.
