Responses in roots accounts for differential salt tolerance in quinoa accessions

Bazihizina N1,2, Cuin TA1, KianiPouya A1 and Shabala S1

  1. Tasmanian Institute for Agriculture, College of Science and Engineering, University of Tasmania.
  2. Department of Agrifood Production and Environmental Sciences, University of Florence.

Epidermal bladder cells (EBCs) play a key role in the salt tolerance of salt-secreting halophytes by acting as an external salt dump under conditions of excess Na. Nevertheless, after testing the salinity tolerance of more than 100 quinoa accessions, we observed dramatic differences in EBC density. Increase in EBC density were not always correlated with greater salt tolerance. This suggests that some quinoa accessions are capable of enhanced salt tolerance without relying on external Na sequestration. To elucidate possible mechanism(s) underlying this enhanced tolerance in accessions with low EBC density, four accessions with contrasting salt tolerance and EBC density were selected. Different physiological and electrophysiological parameters were evaluated after long and short-term treatment with NaCl. The combined data indicate that additional tolerance mechanisms operate in roots rather than shoots in salt tolerant accessions. In particular, our data indicate a greater reactive oxygen scavenging capacity in tolerant accessions, which improves root functionality following salt stress. This ultimately results in improved leaf stomatal regulation and enhanced salt tolerance.