Hydrochar mitigates salt toxicity and oxidative stress in maize plants

Abstract

ABSTRACT This experiment was conducted to investigate the effects of hydrochar addition to soil (i.e., non-hydrochar, 20, 50, 70 and 100 g kg−1 soil) on different nutrients contents (sodium, potassium, calcium, magnesium, iron, and zinc), enzymatic (catalase, peroxidase, and superoxide dismutase) and non-enzymatic antioxidants (phenolic compounds, ascorbic acid, and α-tocopherol) activities and growth of Zea mays (cv. KC-S 260) under different levels of salinity (i.e., non-saline, 5 and 10 dS m−1 NaCl). The application of hydrochar in different rates decreased sodium uptake and increased non-enzymatic antioxidants in plant tissues and consequently reduced the generation of oxygen radicals, hydrogen peroxide, lipid peroxidation, and enzymatic activities of antioxidants under salt stress. Hydrochar enriched the plant tissues (leaf and root) by potassium, calcium, magnesium, iron, and zinc which caused to improve the plant growth under saline and non-saline conditions. Hydrochar application at the rate of 70 and 100 g kg−1 soil alleviated salinity effects more than other rates. Increasing iron and zinc contents by hydrochar treatments in plant tissues had the most important role in improving shoot growth of maize plants. The results supported that hydrochar can help to protect maize against salt toxicity by mitigating oxidative stress and maintaining ionic balance.