Synergistic effects of biochar and abscisic acid improved root morphology, antioxidant defense system and decreased availability and bioaccumulation of cadmium in Triticum aestivum (L.) under cadmium stress

Biochar (BC) and abscisic acid (ABA) may have positive effects on metal-stressed plants but their interactive role for cadmium (Cd) availability in agricultural soils remained unclear which was evaluated in current study. The results depicted that Cd-induced oxidative stress significantly reduced the growth of wheat, physiology and antioxidant responses. Co-application of BC (2.5%) and ABA (20 μmol L -1 ) improved the wheat growth by minimizing Cd accumulation and translocation than their single use. The co-application of these amendments significantly increased the tissues biomass by 36%, total root volume (29%), root surface area (44%), Chl-a and Chl-b by 59% and 55% at 10 mg kg -1 Cd than control. Cd increased the proline, MDA and H 2 O 2 contents, while BC and ABA applications ameliorated Cd-induced oxidative injury by boosting the enzyme activities of catalase by 46%, ascorbate-peroxidase by 46% and peroxidase by 37% at 10 mg kg -1 Cd. The Cd treatment significantly increased Cd in soil, root and shoot tissues of wheat. Co-application reduced DTPA-extractable soil Cd by about 3-fold at 5 mg kg -1 and by about 1.8-fold at 10 mg kg -1 , as compared to respective controls. BC + ABA reduced Cd biological accumulation by 35% and 33% and Cd translocation by 21% and 9% at 5 and 10 mg kg -1 Cd levels than control. It was concluded that BC+ABA application significantly enhanced the growth of wheat, physiology, antioxidant enzymatic potential and minimized Cd bioaccumulation which may be an effective Cd immobilization strategy in soil. • Cadmium (Cd) alone caused the reduction in growth of wheat • Biochar+ABA increased the growth of Cd-stressed wheat • Biochar+ABA decreased Cd concentration in tissues of wheat • Biochar+ABA decreased soil bioavailable Cd concentration