CHELATE-ENHANCED REDUCTION OF HEXAVALENT CHROMIUM (CR⁶⁺) TOXICITY IN WHEAT SEEDLINGS: EFFECTS ON GROWTH, PHYSIOLOGICAL, BIOCHEMICAL, AND METAL UPTAKE RESPONSES

Abstract

Hexavalent chromium (Cr⁶⁺) toxicity adversely affects plant growth and metabolism, limiting crop productivity. This study evaluated the effects of Cr⁶⁺ (20–80 mg L⁻¹) and the mitigating role of chelating agents (DTPA and EDTA, 20 mg L⁻¹) on growth, physiological, biochemical, and metal accumulation responses of wheat (Triticum aestivum L. cv. HD-2428) under pot culture conditions. Chromium stress caused a dose-dependent reduction in shoot and root growth, biomass, photosynthetic pigments, proteins, and soluble sugars, while proline accumulation increased in response to stress. Chelate application significantly alleviated Cr-induced toxicity by improving growth, pigment content, and biochemical attributes. It also enhanced chromium uptake and accumulation, as evidenced by increased bioconcentration factor (BCF) and total accumulation rate (TAR), while maintaining a high translocation index (Ti). The tolerance index (TI) increased to >1.0 under chelate treatment, indicating improved plant tolerance. These findings demonstrate that DTPA and EDTA effectively reduce Cr⁶⁺ toxicity while enhancing chromium accumulation, supporting their potential application in wheat-assisted phytoremediation of chromium-contaminated soils.