* E-Mail: J.Bose@westernsydney.edu.au

Salt stress severely inhibits photosynthesis in wheat, affecting growth and yield. Wheat generally excludes sodium and chloride ions from photosynthetic tissue to cope with salt stress. However, keeping salt away from photosynthetic tissue comes with additional energy costs to fuel salt exclusion mechanisms and the synthesis of organic compatible solutes resulting in reduced overall growth.

To minimise the energy demand and to improve overall salt tolerance in wheat, germplasms exhibiting enhanced photosynthesis while accumulating salt inside the leaf tissue must be identified. In this study, we examined the ability of leaf tissue to maintain its greenness and photosynthesis in a range of cereals containing A, B, D and R genomes (Avena sativa, Hordeum vulgare, Aegilos tauschii, Triticum monococum, T. durum, three varieties of T. aestivum, Secale cereale, and a hybrid between T.aestivum and S. cereale) by exposing whole plants and excised leaves to 150mM and 50 mM of NaCl, respectively.

We measured chlorophyll content, photosynthetic parameters, dead leaf percentage, leaf ion (Na and K) concentrations, and Na distribution within the mesophyll cell compartments (chloroplasts, vacuole and cytosol) using Na-selective CoRoNaGreen dye. Our findings suggested that enhanced photosynthesis and the stay-green trait of wheat under salt stress are linked to the inheritance of the D genome.

Subsequently, we tested several wheat cultivars and landraces containing the D genome for enhanced tissue tolerance. Our results showed that there was a striking difference in leaf tissue tolerance and greenness maintenance among different cultivars of T. aestivum despite having the D genome.