Salinity Stress in Tomato Plants

Takagi et al. (2008) grew well watered and fertilized tomato [Solanum lycopersicum (formerly Lycopersicon esculentum) L. cv. Momotarou] seedlings for two weeks at two different levels of irrigation-water salinity (0 or 100 mM NaCl) in 3-L pots inside the greenhouse of Hiroshima University, Japan, at atmospheric CO₂ concentrations of either 370 or 1000 ppm, while measuring various plant properties and physiological responses.

Results indicated that "salt-stress treatment severely decreased whole-plant biomass," as well as "leaf photosynthesis and transport of carbon assimilates," but that "the impact of stress on these activities was alleviated under elevated CO₂ concentration." This alleviation, as they describe it, "was promoted when sink activity relative to source activity was higher," which they say was "probably owing to improvement of oxidative stress," due "at least partially to the higher constitutive antioxidant enzymes' activities," as well as improved water status "through stomatal closure at high CO₂ concentration."

In considering their findings, the seven scientists state that their study "corroborates earlier reports that the interaction between salinity stress and CO₂ concentration result[s] in the alleviative effect of elevated CO₂ on the negative effects of salinity on plant growth," providing yet another indication of the ability of earth's plants to function ever more robustly and to successfully overcome various environmental challenges as the air's CO₂ content continues to climb ever higher.