Biochar mitigates salt stress by regulating nutrient uptake and antioxidant activity, alleviating the oxidative stress and abscisic acid content in cabbage seedlings

A pot experiment was conducted to investigate the growth, physiology, and biochemistry of cabbage seedlings in response to salinity stress with biochar. The study was conducted as factorial completely randomized design with two factors; salinity levels (0 and 150 mM NaCl) and biochar doses (weighed at the rate of 0%, 2.5%, and 5% by soil weight). Growth parameters such as stem diameter, leaf area, shoot fresh weight, root fresh weight, shoot dry weight, and root dry weight of cabbage seedlings treated with 150 mM NaCl were lower than the control. Biochar amendments improved the growth parameters of cabbage seedlings under salt stress and normal conditions compared to the control. Salinity stress conditions induced the increase in malondialdehyde (MDA), hydrogen peroxide (H2O2), proline, and sucrose content while biochar lowered the concentration of these parameters. Salinity stress conditions caused decrease in the plant nutrient element content of leaf and root of cabbage seedlings except for Na and Cl while amendment of biochar into soil media enhanced the plant nutrient element content of leaf and root of cabbage seedlings. Salinity increased the Na and Cl content, whereas biochar decreased Na and Cl content of cabbage seedlings. In conclusion, biochar mitigated the negative impact of salinity stress on cabbage seedlings by reduction of Cl and Na concentration, and reactive oxygen species (ROS) production, regulating abscisic acid (ABA) content, antioxidant enzyme activity and plant nutrient element content.