* 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 screened for variations in chloroplast traits and functions in several cultivars of bread wheat Triticum aestivum (AABBDD) and its relatives Aegilos tauschii (DD), T. monococum (AA), T. durum (AABB) by exposing whole plants to 150mM NaCl.

We measured changes in chloroplast shape, chloroplast number per cell, chloroplast sodium ion accumulation (using Na-selective CoRoNaGreen dye), chlorophyll content and overall photosynthetic performance.

Our findings suggested that maintaining chloroplast shape and exerting greater control over sodium accumulation inside the chloroplasts are key to maintaining leaf greenness and enhanced photosynthesis in wheat under salt stress.