Improvement of Physiological and Biochemical Traits of Sorghum (Sorghum bicolor L.) by Application of Biochar and Salicylic Acid in Soils Contaminated with Lead Heavy Metal

This study was to investigate the effect of biochar and salicylic acid on sorghum (Sorghum bicolor var.Speed feed) physiological and biochemical changes under lead stress conditions

The experiment was carried out as a factorial experiment in a completely randomized design with 4 replications in greenhouse in 2019. The treatments of this experiment include five levels of lead (0, 400, 800, 1200 and 1600 mg of lead per kg of soil from lead nitrate source), two levels of biochar (no consumption and consumption of biochar 20 g of biochar per kg of soil) and two levels of acid salicylic acid (including non-foliar and 2 mM salicylic acid foliar).

The results showed that consumption of biochar and salicylic acid increased chlorophyll a by 5.25 and 4.81%, respectively. The highest amount of carotenoids was obtained in the combined treatment of biochar consumption and salicylic acid foliar application. Phenol levels increased with increasing lead levels, which was greater in plants sprayed with salicylic acid. Also, the amount of flavonoids increased by 10.57% under the influence of biochar consumption. The interaction of biochar and salicylic acid increased proline, and this increase was 88.48% compared to the control.

Therefore, the use of these cheap and available materials in the soil can be a suitable and cost-effective method to reduce soil contamination to increase the metabolic activity of sorghum plant, improve plant resistance to lead stress.