Anthocyanin accumulation, inflorescence dry weight and total cannabidiol content have different temperature optima in Cannabis sativa

Abstract

Background: Limited information exists on how temperature affects phytocannabinoids and anthocyanin accumulation and inflorescence dry weight yield in Cannabis sativa. Understanding how temperature influences these traits is essential for refining cultivation practices, meeting market demands, and developing novel cannabis cultivars with improved agronomic, medicinal, and aesthetic attributes.

Methods: In this study, a day-neutral inbred population with uniform expression of purple pigmentation on the leaves and flowers was used to explore how temperatures ranging from 0.5 to 22 °C impacts inflorescence dry weight, cannabidiol (CBD) percentage, and anthocyanin accumulation in cannabis. Data on inflorescence dry weight (g/plant), CBD (%), and anthocyanin concentration (mg∙L^{− 1}) in the primary inflorescence of each plant were collected and analyzed.

Results: Total CBD concentration and inflorescence dry weight yield increased with increasing temperature– likely a result of plant maturity rather than temperature stimuli. Anthocyanin accumulation was significantly affected by temperature stimuli, exhibiting peak production levels at constant temperatures of 8 °C and 15 °C.

Conclusions: CBD concentration and inflorescence dry weight predominantly correlate with plant maturity, whereas anthocyanin accumulation is responsive to variations in environmental temperature. Maximum anthocyanin levels at 8 °C and 15 °C, along with reduction at 0.5 °C and 22 °C, suggests distinct temperature-dependent regulatory pathways for anthocyanin biosynthesis in cannabis, separate from those influencing CBD biosynthesis and inflorescence dry weight. Modeling anthocyanin concentration, CBD concentration, and total inflorescence dry weight across various temperature treatments could optimize desired floral qualities and other traits associated with yield in cannabis.

Supplementary Information: The online version contains supplementary material available at 10.1186/s42238-025-00311-w.

Keywords: Anthocyanin; CBD; Cannabidiol; Cannabis; Temperature effects.

Fig. 1

Inflorescence dry weight (IDW) observed for five temperature treatments across two replicated experiments (1 and 2). The trend line represents the linear relationship between temperature and IDW. Error bars indicate the standard deviation of IDW at different temperatures, while grey shading indicates the confidence interval (95%) for the linear regression line

Fig. 2

Total CBD (TCBD), measured as a percent dry mass, observed for five temperature treatments across two replicated experiments (1 and 2). The trend line shows the relationship between temperature and TCBD. Error bars indicate the standard deviation for TCBD at different temperatures, while grey shading indicates the confidence interval (95%) for the linear regression line

Fig. 3

Photographs of plants after their respective temperature treatments. Plants were removed from their growth chambers and photographed 23 and 30 days into their treatments, respectively for replicates 1 and 2. Each photo represents 13-15 plants

Fig. 4

Total Monomeric Anthocyanins (TMA) observed across five temperature treatments and two replicated experiments (1 and 2). Boxplots display the distribution of TMA levels among individuals exposed to various temperature treatments. Boxplots are colored based on experimental conditions (constant or fluctuating). Letters above the boxplots indicate whether treatments were significantly different from each other (p < 0.05). Significance was determined using a post hoc Tukey’s HSD test following one-way ANOVA. The trend line represents the quadratic relationship between temperature and TMA while the light blue shading represents the confidence interval (95%) for the trendline

Fig. 5

. Correlation between traits for two replicated temperature treatment experiments. IDW: Total Dry Weight (g/plant), TAS: Total Anthocyanin Score, TMA: Total Monomeric Anthocyanins (mg∙L^− 1), TCBD: Total CBD (%). Significant positive correlations were observed for TAS and TMA (p < 0.001), TAS and IDW (p < 0.001), and TCBD and IDW (p < 0.05)

Fig. 6

Normalized trait values for inflorescence dry weight (Green), total CBD (Orange), and total monomeric anthocyanins (Purple) for cannabis plants grown in various temperature treatments. The trendlines represent the overall modeled relationship between temperature and the three traits