Paper Reviewed
Li, S., Li, Y., Gao, Y., He, X., Zhang, D., Liu, B. and Li, Q. 2020. Effects of CO2 enrichment on non-structural carbohydrate metabolism in leaves of cucumber seedlings under salt stress. Scientia Horticulturae 265: 109275.

In a CO2 enrichment study that really delves into the details, Li et al. (2020) investigated the mechanisms controlling the ameliorative effects of elevated CO2 on cucumber (Cucumis sativus, cv. Jinyou 35) seedlings experiencing salt stress.

The cucumber plants were grown in open-top greenhouses under one of two CO2 concentrations (400 or 800 ppm) and one of two levels of salinity (0 or 80 mmol L^-1 NaCl, corresponding to control and salt stress conditions, respectively). After 7 days of treatment, leaf samples were collected and analyzed from the third fully developed leaf from the base of the plant. Measurements included those pertaining to sucrose metabolism, the glycolytic pathway, tricarboxylic acid cycle intermediates and key enzyme activities.

Results revealed that salt stress negatively impacted the afore-mentioned processes and enzymes whereas elevated CO2 "facilitated the normal metabolism of sucrose, providing more substrates (fructose and starch) for respiratory metabolism, effectively participating in the glycolytic pathway and tricarboxylic acid cycle, and providing more energy to prevent salt-induced injury." Or put in non-scientific terms, Li et al. report that "the negative effects of salt stress were alleviated under enriched CO2 conditions and resistance [to salt stress] was enhanced." And that is great news for plants and crops that currently grow on salt stressed lands. In the future, those plants and crops will experience enhanced growth and yield thanks to rising levels of atmospheric CO2, which are helping to reverse the deleterious impacts of salinity stress.