## 1 Introduction
### Role of Trichomes in Cannabinoid Synthesis and Economic Relevance  
Cannabis is a dioecious plant [11] that produces both glandular and non-glandular trichomes on the surface of leaves and other parts of the plant body [12]. However, it is the capitate-stalked glandular trichomes on modified leaves (perigonal bracts) surrounding female flowers that are the primary site of phytocannabinoid production [13]. On the other hand, the male plants produce lower amounts of cannabinoids compared to female plants [14]. These trichomes not only facilitate the production of valuable secondary metabolites, but also defend the plant from environmental stressors. The resinous secretions that are rich in cannabinoids, terpen, and other compounds can deter herbivory by conferring a bitter taste or sticky texture, while also protecting against UV radiation and certain pathogens [15]. Consequently, trichome density (Figure 1) may be correlated with total cannabinoid yield [16], making it an important breeding and cultivation target not only for cannabinoid levels, but also for flower esthetics and quality.  
Figure 1: Trichome density counting on a cannabis bract using a digital microscope. The top panel displays a microscopic image of the cannabis bract, featuring glandular trichomes (clear, globular structures). The bottom panel illustrates the image after processing in ImageJ software 1.54p (Image), U.S. National Institutes of Health, Bethesda, MD, USA, [[https://imagej.net/ij/](https://imagej.net/ij/)]([https://imagej.net/ij/](https://imagej.net/ij/))), accessed on 14 November 2023.  
Given their myriad therapeutic possibilities, from pain management to seizure control, high-cannabinoid varieties of cannabis have become increasingly valuable in medical markets [1]. These varieties often require optimized growing conditions--an optimal light spectrum, optimal nutrition, and targeted hormone applications, especially when supported by a standardized propagation method [17]--to boost glandular trichome development. For producers, maximizing trichome density could translate to higher potency and improved profit margins. As the global demand for high-cannabinoid cultivars increases and regulatory landscapes evolve, there is a critical need for evidence-based agronomic practices that optimize cannabinoid yield and quality. For researchers, understanding the physiological triggers that upregulate trichome biosynthesis helps to unravel the complexities of plant defense and specialized metabolism. Amid conventional breeding and modern genetic techniques, phytohormones--particularly jasmonates (JAs)--have emerged as potent tools to elevate secondary metabolite content. The production of secondary metabolites in cannabis is linked with the accumulation of cannabinoids, which can affect the yield of THC or CBD, depending on the final goal of growers [18]. Jasmonates are central to plant defense signaling, activating pathways that synthesize protective compounds and physical structures, such as trichomes [19]. MeJA has been particularly noted for enhancing glandular trichome formation and promoting the accumulation of specialized metabolites, including cannabinoids [20]. One promising avenue of research explores how jasmonates, plant hormones recognized for their influence on trichome development and secondary metabolism, shape these traits in cannabis. However, the current literature remains scattered across studies on different hormonal interactions, trichome biology, and cannabinoid pathways, making it challenging for researchers and cultivators to apply these findings holistically. This review aims to bridge this gap by synthesizing existing knowledge on jasmonate's mechanistic role and its integration with broader hormonal networks in cannabis. By examining these factors, we aim to provide a clearer understanding of how jasmonate and related hormonal pathways can be strategically leveraged to improve cannabinoid production.