Physiological responses and adoptive mechanisms in oat against three levels of salt stress

To identify the propagation mechanisms and the adaptive strategies of oat seedlings exposed to NaCl, NaHCO3 and Na2CO3 the main salts in the soils of the salt-alkali grasslands of the Songnen Plain of China, growth rates and physiological indices of oat seedlings were measured in plants grown in soils with different concentrations (48-144 mmol L-1) of the three salts. The results demonstrated that although oat seedlings survival rates were unaffected by NaCl stress, the tiller number, plant height, and shoot and root dry weights decreased with increasing salt concentration, in the order of Na2CO3＞NaHCO3＞NaCl. In addition, propagation mechanisms higher concentrations of Na+ accumulated in the shoots and roots of oat seedlings under Na2CO3 stress and NaHCO3 stress than in seedlings under NaCl stress. Reductions in concentrations of K+ were also greater under both Na2CO3 and NaHCO3 stress than NaCl, especially in the roots. Large amounts of Cl－ and proline were found to accumulate in oat seedlings, most likely as a strategy for maintaining osmotic and ionic homeostasis under NaCl stress.