Photosynthetic Performance and Potency of <i>Cannabis sativa</i> L. Grown under LED and HPS Illumination
- 1 Rubisco Research and Consulting, Sacramento, USA
- 2 Oaksterdam University, Oakland, USA
- 3 Dynamite Ag, Inc.
Abstract
Light-emitting diodes (LEDs) can be used as an energy efficient alternative to high-pressure sodium (HPS), which have historically been the standard for supplemental lighting in cannabis cultivation. However, there is a lack of scientific understanding in the cannabis industry regarding plant physiology, which has resulted in the adoption of cannabis cultivation methods based on hearsay rather than scientific research. The goals of this study were to 1) compare LED lighting options that are commonly used in the cannabis industry and 2) compare the top performing LED light with an industry standard HPS light. Specifically, three LED lights were compared (California Light Works ((SolarSystem 1100), BIOS Lighting (Icarus Gi2), and Fluence Bioengineering (now Fluence by Osram) (SPYDR xPLUS)), based on light distribution, leaf temperature, and photosynthetic performance indices. The LED versus HPS comparison was based on light response curves measured at photosynthetic photon flux densities (PPFD) of (0, 100, 200, 300, 400, 500, 750, 1000, 1250, 1500, 1750 and 2000 μmol ∙ m − 2 ∙ s − 1 ), carbon assimilation rates ( A ) μmol CO 2 m − 2 ∙ s − 1 using a LiCor-6800 and resulting cannabinoid potency (THCA). The SPYDR xPLUS-Fluence by Osram had the highest performing LED light used in the LED comparison. At the suggested distance from bulb to canopy in the HPS versus LED comparison (6 inches for LEDs and 4 ft for HPS), carbon assimilation rates displayed a 142% percent increase in plants grown under LED vs. HPS with average photon flux densities of 795 and 298 μmol ∙ m − 2 ∙ s − 1 for LED and HPS, respectively. All cultivars of Cannabis sativa L. showed increased cannabinoid potency when grown under LED illumination. The results of this study provide further insight regarding the selection of supplemental light to achieve maximum productivity of Cannabis sativa L.
- Lawlor, D.W. (1995) Photosynthesis, Productivity and Environment. Journal of Experimental Botany, 46, 1449-1461. https://doi.org/10.1093/jxb/46.special_issue.1449
- Casal, J.J. and Yanovsky, M.J. (2005) Regulation of Gene Expression by Light. International Journal of Developmental Biology, 49, 501-511. https://doi.org/10.1387/ijdb.051973jc
- Casal, J.J., Fankhauser, C., Coupland, G. and Blázquez, M.A. (2004) Signalling for Developmental Plasticity. Trends in Plant Science, 9, No. 6. https://doi.org/10.1016/j.tplants.2004.04.007
- Chen, M., et al. (2010) Arabidopsis HEMERA/pTAC12 Initiates Photomorphogenesis by Phytochromes. Cell, 141, 1230-1240. https://doi.org/10.1016/j.cell.2010.05.007
- (2019) The Global Cannabis Report.
- Lydon, J., Teramura, A.H. and Coffman, C.B. (1987) UV-B Radiation Effects on Photosynthesis, Growth and Cannabinoid Production of Two Cannabis sativa Chemotypes. Photochemistry and Photobiology, 46, 201-206. https://doi.org/10.1111/j.1751-1097.1987.tb04757.x
- Tang, K., Struik, P.C., Amaducci, S., Stomph, T.-J. and Yin, X. (2017) Hemp (Cannabis sativa L.) Leaf Photosynthesis in Relation to Nitrogen Content and Temperature: Implications for Hemp as a Bio-Economically Sustainable Crop. GCB Bioenergy, 9, 1573-1587. https://doi.org/10.1111/gcbb.12451
- Bourget, C.M. (2008) An Introduction to Light-Emitting Diodes. Hort Science, 43, 1944-1946.
- Massa, G.D., Kim, H.-H., Wheeler, R.M. and Mitchell, C.A. (2008) Plant Productivity in Response to LED Lighting. Hort Science, 43, 1951-1956.
- Morrow, R.C. (2008) LED Lighting in Horticulture.
- Hogewoning, S.W. (2012) On the Photosynthetic and Developmental Responses of Leaves to the Spectral Composition of Light.
- Demmig-Adams, B. and Adams III, W.W. (1992) Photoprotection and Other Responses of Plants to High Light Stress. Annual Review of Plant Physiology and Plant Molecular Biology, 43, 599-626. http://www.annualreviews.org/ https://doi.org/10.1146/annurev.pp.43.060192.003123
- Bilodeau, S.E., Wu, B.-S., Rufyikiri, A.-S., MacPherson, S. and Lefsrud, M. (2019) An Update on Plant Photobiology and Implications for Cannabis Production. Frontiers in Plant Science, 10. https://doi.org/10.3389/fpls.2019.00296
- Backer, R., Schwinghamer, T., Rosenbaum, P., et al. (2019) Closing the Yield Gap for Cannabis: A Meta-Analysis of Factors Determining Cannabis Yield. Frontiers in Plant Science, 10. https://doi.org/10.3389/fpls.2019.00495