Responses of Selected C3 and C4 Halophytes to Elevated CO 2 Concentration under Salinity

Halophytes have superior capacity to withstand soil salinity and are appropriate resources to study the mechanism of salt tolerance which can be harnessed to develop crops to withstand salinity. In this communication, we report the effect of salinity (200 mM NaCl) and elevated carbon dioxide (CO₂) treatments in tandem, on select halophytes that have different photosynthetic pathways: C3 and C4. The plants were raised in ambient (380 ppm) and enriched (500 ppm) concentrations of CO₂ using a mini-FACE facility. Total chlorophyll content, total soluble sugar concentration, lipid peroxidation level and electrolyte leakage were measured from fresh leaf samples collected at different time points. The results show a positive effect for elevated CO₂ concentration on salt tolerance in both C3 and C4 plants, and indicate that halophytes may benefit from rising atmospheric CO₂ concentration. The results also suggest that C4 halophytes may benefit from the rising atmospheric CO₂ concentration than C3 halophytes.