The effects of humic acid and chelate applications on some morphophysiological properties and antioxidant enzyme activities of ornamental cabbage (Brassica oleracea var. acephala) under boron stress

The increase of industrialization, the overuse chemical fertilisers and mining activities are brought about heavy metal-led environment pollution, especially agricultural land. This leads to more boron (B) contamination and accumulation in the soil. This study was carried out to evaluate B uptake from the soil of ornamental cabbage grown as a hyperaccumulator plant under B stress conditions in a controlled greenhouse on plant morphology, physiology, antioxidant enzyme activity the effects of humic acid (50mg kg-1 B + 2% humic acid -HA) and chelate [0.5 g kg-1 chelate (EDTA)] applications. According to the results, especially chelate application significantly increased the B uptake of the plant, and B accumulation was higher in the plant shoot than in the root. However, HA and chelate applications brought out the negative effects of B stress on growth and physiological characteristics and reinforced the increases in malondialdehyde (MDA) content and superoxide dismutase (SOD) and catalase (CAT) enzyme activities. In conclusion, this study shows that HA and chelate additions increase the efficiency of the use of ornamental cabbage to remove excess boron from the soil. According to these results, it is possible to increase the use of ornamental cabbage for phytoremediation purposes, especially with chelate application.