Terpenes are aromatic compounds that give cannabis some of its most distinct aromas from citrus and berry, to more earthy tones. Many species of plants produce and emit terpenes in a diurnal, or daily cycle that is regulated by a complex web of signaling. There are also many plants that emit terpenes at night to attract nocturnal pollinators (Marinho et al., 2014346). Regardless of when the terpenes are produced or emitted, these processes are often dependent upon cues derived from natural light/dark cycles via a native circadian clock (Dudareva et al., 2004). Several light-sensitive pigments are involved in these processes of production and emission, and the different photoreceptors are dependent upon different wavelengths of light to be activated or deactivated. Emission of terpenes is a process that is entirely dependent upon phytochromes and red/far-red light cues in most plant species (Flores and Doskey, 2015). For example, repeated light/dark phytochrome signaling is necessary for the emission of terpenes in tobacco plants (Roeder et al., 2007). Based on previous findings, we hypothesized that a lack of red light and phytochrome-mediated light/dark signaling on the part of the plant is responsible for an increase in terpene content in cannabis. The plant continues to synthesize terpenes, but a lack of red light to trigger the Pr-Pfr shift results in a lack of terpene emission by the plant, thus causing the terpenes to accumulate in the maturing flowers. REFERENCES Dudareva N, Pichersky E, Gershenzon J. Biochemistry of Plant Volatiles. Plant Physiology. 2004;135(4):1893- 1902. Flores, R.M., Doskey, P.V., Estimating Terpene and Terpenoid Emissions from Conifer Oleoresin Composition. Atmospheric Environment. 2015. 113, 32-40. Marinho, C.R.; Souza, C.D.; Barros, T.C.; Teixeira, S.P.; Dafni, A. Scent glands in legume flowers. Plant Biology , Volume 16 (1) – Jan 1, 2014 Roeder S, Hartmann AM, Effmert U, Piechulla B (2007) Regulation of simultaneous synthesis of floral scent terpenoids by the 1,8-cineole synthase of Nicotiana suaveolens. Plant Mol Biol 65: 107-12 Abstract Sound waves technology has been applied to different plants. It has been found that sound waves were at different frequencies, sound pressure levels (SPLs), exposure periods, and distances from the source of sound influence plant growth. Experiments have been conducted in the open field and under greenhouse growing conditions with different levels of audible sound frequencies and sound pressure levels. Sound waves at 1 kHz and 100 dB for 1 h within a distance of 0.20 m could significantly promote the division and cell wall fluidity of callus cells and also significantly enhance the activity of protective enzymes and endogenous hormones. Sound waves stimulation could increase the plant plasma-membrane H+-ATPase activity, the contents of soluble sugar, soluble protein, and amylase activity of callus. Moreover, sound waves could increase the content of RNA and the level of transcription. Stress-induced genes could switch on under sound stimulation. Sound waves at 0.1–1 kHz and SPL of (70±5) dB for 3 h from plant acoustic frequency technology (PAFT) generator within a distance ranged from 30 to 60 m every other day significantly increased the yield of sweet pepper, cucumber and tomato by 30.05, 37.1 and 13.2%, respectively. Furthermore, the yield of lettuce, spinach, cotton, rice, and wheat were increased by 19.6, 22.7, 11.4, 5.7, and 17.0%, respectively. Sound waves may also strengthen plant immune systems. It has been proved that spider mite, aphids, gray mold, late blight and virus disease of tomatoes in the greenhouses decreased by 6.0, 8.0, 9.0, 11.0, and 8.0%, respectively, and the sheath blight of rice was reduced by 50%. This paper provides an overview of literature for the effects of sound waves on various growth parameters of plant at different growth stages. https://doi.org/10.1016/S2095-3119(13)60492-X