Paper Reviewed
Dhami, N., Tissue, D.T. and Cazzonelli, C.I. 2018. Leaf-age dependent response of carotenoid accumulation to elevated CO2 in Arabidopsis. Archives of Biochemistry and Biophysics 647: 67-75.

Dhami et al. (2018) investigated the effects of elevated CO2 on thale cress (Arabidopsis thaliana) photosynthesis, development and growth. The plants were growth for four weeks in controlled-environment chambers under either ambient (400 ppm) or elevated (800 ppm) atmospheric CO2 levels.

Their analysis revealed that elevated CO2 increased net photosynthesis by 60%, rosette area by 20%, number of rosette leaves per plant by 16%, shoot biomass (fresh and dry) by 60% and seed yield by 30% (see figure 1 below). In addition, Dhami et al. report that there was a significant ~20% increase in total carotenoid content in recently-emerged younger leaves (but not in older ones) in plants growing in the elevated CO2 treatment compared to ambient CO2 conditions, suggesting that "younger leaves utilize additional carbon from enhanced photosynthesis in elevated CO2 to increase carotenoid content." And since the authors note in the abstract of their paper that "carotenoids contribute to photosynthesis, photoprotection, phytohormone and apocarotenoid biosynthesis in plants," and that "carotenoid-derived metabolites control plant growth, development and signaling processes," it would appear that we have another good reason to celebrate the modern rise in atmospheric CO2!

Figure 1. Percentage increases in the number of rosette leaves, rosette area, rosette fresh weight (FW), rosette dry weight (DW) and seed yield under elevated CO2. Source: Dhami et al. (2018).