Abstract

Background: Heavy metal stress, particularly cadmium (Cd), poses a serious threat to crop productivity by impairing growth, physiology, and biochemical functions. For the management of Cd-stressed soils, intervention is at the utmost. Therefore, this study aimed to evaluate the effect of salicylic acid (SA) on biochemical, physiological and morphological growth attributes of wheat (Triticum aestivum L.) variety Punjab 2011 under cadmium chloride (CdCl2) stress. 
Method: The SA was applied at 10-4 mol/L as a seed soaking solution before sowing of seeds in the pots. The soil was contaminated with different concentrations of CdCl2 (50 mg/kg, 100 mg/kg and 200 mg/kg soil). 
Results: The CdCl2 stress demonstrated adverse effects and decreased seed germination (%), root fresh weight, root dry weight, chlorophyll “a”, and chlorophyll “b” content of wheat, significantly (P<0.05). The CdCl2 stress resulted in the accumulation of total soluble phenolics and higher antioxidant activity in roots and leaves of maize. Both under unstressed as well as CdCl2-induced stress conditions, SA application significantly (P<0.05) improved growth indices, including seed germination (%), index, index rate, shoot fresh and dry weight, root fresh and dry weight, and chlorophyll “a”, and chlorophyll “b” content. It was also observed that SA exhibited stimulatory effects on the accumulation of phenolic compounds under CdCl2 stress in both leaves and roots. 
Conclusion: CdCl2 had toxic effects and resulted in decreased different growth attributes, increase in carotenoid pigments and total soluble phenolics. The application of the SA significantly improved the overall health of T. aestivum crop under Cd-stressed soil.