Evaluating growth platforms and stress scenarios to assess the salt tolerance of wheat plants

Crops are routinely subjected to a combination of different abiotic stresses. Simplified platforms, stress scenarios and stress protocols are used to study salt tolerance under largely controlled and uniform conditions that are difficult to extrapolate to real arid and semiarid field conditions. To address the latter deficit, this work compares a realistic stress protocol (for salinity alone, drought alone and combined salinity plus drought stress) simulating a field environment in large containers to equivalent results from a more artificial pot environment. The work was based on two wheat cultivars known to differ in their salt tolerance (salt-sensitive Sakha 61 and salt-tolerant Sakha 93). Our results showed that previously established differences in the salt tolerances of the two wheat cultivars were no longer valid when the plants were exposed to a combined stress of salinity plus drought, regardless of the growth platform. Furthermore, in comparing a simulated field root-environment (containers) with pots, our results showed an interactive effect between the different treatments and platforms for both of the investigated cultivars. We conclude that a combined salinity+drought stress scenario and a reliable growth platform are of utmost importance in screening for salt tolerance of spring wheat. In future studies, increased emphasis should be placed on combining salinity with drought stress in well suited platforms to better mimic real field conditions where salinity is present.