Abstract
Boron (B) toxicity is an important environmental constraint that limits crop productivity. Salicylic acid (SA) and thiamin participate in the processes underlying plant adaptations to certain types of abiotic and biotic stress. This study aimed to investigate the individual and combined effects of SA or thiamin and B on physiological attributes of wheat under normal and B-toxicity conditions. Seeds were soaked in SA or thiamin and excess B was applied for 10-day after planting the seedlings. Growth parameters, photosynthetic pigments, B and some elements concentrations, hydrogen peroxide (H
2
O
2
), proline, other free amino acids, soluble proteins and carbohydrates were measured. Application of SA or thiamin showed an increase in tolerance towards high B as indicated by H
2
O
2
, amino acids, soluble proteins and carbohydrates contents. The results support the conclusion that SA and thiamin alleviate B toxicity not at the level of B content but by affecting other elements and osmo-protective metabolite.