The aim of this study was to determine the responses of some selected wheat varieties to high ambient C02 under salinity stress at seedling stage. The results revealed that applied salinity affected the growth of all the varieties while high (700 ppm) concentration of C02 substantially reduced the adverse effect of salinity and enhanced growth, by improving osmolytes (free proline, glycinebetaine and soluble sugars) accumulation. Furthermore, elevated C02 increased the contents of K+ and enhanced K+ INa+ ratio, whilst decreasing the contents Na + and cr as compared to respective control, although varietal differences were evident. Overall, there was a 6016% increase in growth attributes and 15020% increase in the K+ contents and K+/Na+ ratio, while reducing the toxic ionic contents. For all the parameters, relatively salt sensitive varieties benefitted greatly from C02 enrichment than the tolerant varieties. In conclusion, increased ambient C02 concentration acted as foliar fertilizer for salinity grown wheat varieties and substantially enhanced the growth, osmotic and ionic characteristics.

• Abdul Wahid(Department of Botany, University of Agriculture) Corresponding author
• Samia Aslam Butt(Department of Botany, University of Agriculture)