Photosynthetic response of Cannabis sativa L., an important medicinal plant, to elevated levels of CO2

Abstract

The effect of elevated CO 2 concentrations (545 and 700 μmol mol −1 ) on gas exchange and stomatal response of four high Δ 9 -THC yielding varieties of Cannabis sativa (HPM, K2, MX and W1) was studied to assess their response to the rising atmospheric CO 2 concentration. In general, elevated CO 2 concentration (700 μmol mol ) significantly (p<0.05) stimulated net photosynthesis (P N ), water use efficiency (WUE) and internal CO 2 concentration (C i ), and suppressed transpiration (E) and stomatal conductance (g s ) as compared to the ambient CO 2 concentration (390 μmol mol −1 ) in all the varieties whereas, the effect of 545 μmol mol −1 CO 2 concentration was found insignificant (p<0.05) on these parameters in most of the cases. No significant changes (p< 0.05) in the ratio of internal to the ambient CO 2 concentration (C i /C a ) was observed in these varieties under both the elevated CO 2 concentrations (545 and 700 μmol mol −1). An average increase of about 48 %, 45 %, 44 % and 38 % in P N and, about 177 %, 157 %, 191 % and 182 % in WUE was observed due to elevated CO 2 (700 μmol mol −1 ) as compared to ambient CO 2 concentration in HPM, K2, MX and W1 varieties, respectively. The higher WUE under elevated CO 2 conditions in Cannabis sativa, primarily because of decreased stomatal conductance and subsequently the transpiration rate, may enable this species to survive under expected harsh greenhouse effects including elevated CO 2 concentration and drought conditions. The higher P N , WUE and nearly constant C i /C a ratio under elevated CO 2 concentrations in this species reflect a close coordination between its stomatal and mesophyll functions.

Hemp (Cannabis sativa L.) leaf photosynthesis in relation to nitrogen content and temperature: implications for hemp as a bio‐economically sustainable crop

“…The present study also indicated that the value of κ 2LL may differ among growth environments. Thirdly, variation in photosynthetic competence among cultivars has been reported for hemp (Chandra et al ., ). As only one cultivar was studied, it is not clear whether the advantage of photosynthetic competence of hemp is persistent across cultivars.…”

“…Chandra et al . (, ,b, ) showed the response of leaf photosynthesis of hemp to irradiance intensity, CO 2 concentration and temperature by measuring gas exchange of leaves from glasshouse‐grown plants. Marija et al .…”

Propagation of Cannabis for Clinical Research: An Approach Towards a Modern Herbal Medicinal Products Development

“…Our studies show that cannabis exhibits higher rate of photosynthesis at high photosynthetic photon flux density (PPFD,~1500 µmolm 2 s -1 ), which is typically sunny summer day in Mississippi (Chandra et al, 2008;Chandra et al, 2015). Further, about a 50% increase in the rate of photosynthesis was observed under doubling of CO 2 concentration as compared to ambient CO 2 concentration (Chandra et al, 2008;Chandra et al, 2011b). Higher humidity is generally~60-75% is recommended at the young vegetative stage of plants whereas a lower range of 50 to 55% is recommended during the flowering stage.…”

An Update on Plant Photobiology and Implications for Cannabis Production

“…(1987) reported that supplementing with UV-B radiation for 3 h daily increased THC concentrations on C. sativa leaves and buds, whereas supplementing with UV-C radiation (100–280 nm) influenced resveratrol and piceid levels (Marti et al., 2014). Photosynthetic responses in C. sativa were measured at different light intensities, temperatures, and CO 2 concentrations (Chandra et al., 2008, 2011a, 2015). Of the environmental conditions tested, the highest net photosynthetic rates occurred at 30°C and 1,500 μmol m −2 s −1 , but this was reduced by nearly 20% when intensity increased to 2000 μmol m −2 s −1 ; no declined trend was observed at any other test temperatures (Chandra et al., 2008).…”