Effects of different doses of cadmium on physiological, biochemical, and phytoextraction potential of mustard (Brassica juncea L.)

This study investigated the physiological and biochemical tolerance and response, cadmium (Cd) accumulation capacity of the mustard plant (Brassica juncea L.) to different doses of Cd (0.0 (control)-, 25-, 50-, 100-, 200-, and 300 ppm) under greenhouse conditions. After harvesting the mustard plant, physiological parameters (plant length, plant fresh and dry weight, roots fresh weight and dry weight), and biochemical parameters such as chlorophyll a (Chl a), and chlorophyll b (Chl b), carotenoids, proline, malondialdehyde (MDA), antioxidant enzymes such as peroxidase (POX), and catalase (CAT) were examined. Cd content was measured in leaves and roots to determine phytoextraction capacity. Cd stress decreases plant and root fresh weight (Fwt) and dry weight (Dwt). Chl a-Chl b, and carotenoid contents 100 ppm of Cd decrease Cd doses increase p≤0.05. The osmolyte molecule proline increased to 100 ppm Cd dose and then declined to 300 ppm. Accumulation of MDA (2.9 to 33.8 nmol g-1 Fwt), H2O2 (2.9 to 30.4 µmol g-1 Fwt), and antioxidant enzymes (POX and CAT) showed an increasing trend with increasing Cd doses, p≤0.05. Cd accumulation in leaves (0.0 to 53.8. mg kg-1 ) and roots (0.0 to 67.7. mg kg-1 ) increased depending on the applied Cd concentration. The highest Cd accumulation was determined at 300 ppm Cd level. These findings suggest that mustard plants can accumulate high levels of Cd in both leaves and roots, indicating that they are hyperaccumulators. As a result, mustard plants can be utilized as phytoremediation plants in Cd-contaminated soils.