Lettuce production and antioxidant capacity are differentially modified by salt stress and light intensity under ambient and elevated CO2

As a consequence of the increasing importance of vegetables in the human diet, there is an interest in enhancing both the productivity and quality of vegetables. A number of factors, including plant genotype and environmental growing conditions, can impact the production and quality of vegetables. The objective of this study was to determine whether elevated CO2, salinity, or high light treatments assayed individually, or salinity or high light in combination with elevated CO2, increased biomass production and antioxidant capacity in two lettuce cultivars. Elevated CO2 and its combination with salinity or high light increased biomass production in both cultivars, while high light treatment alone increased production in green-leaf lettuce but not in red-leaf lettuce. On the other hand, elevated CO2 and its combination with salinity or high light increased the antioxidant capacity of both cultivars, while high light treatment alone increased the antioxidant capacity of red-leaf lettuce, but not of green-leaf lettuce.