Comprehensive Analysis of Phytotoxic Impact of Arsenic on Wheat: From Germination to Grain Yield
摘要
Arsenic (As) contamination in soil and irrigation water poses a major threat to wheat (Triticum aestivum L.) productivity. The present study examined the effects of soil-applied As on wheat (cv. HD2967) using a Petri plate germination assay and a pot experiment conducted at 45, 90, and 140 days after sowing under As concentrations ranging from 25 to 100 mg kg⁻1. Arsenic exposure reduced germination, biomass accumulation, pigment content, nutrient uptake, and enzymatic activities, while inducing oxidative stress. Antioxidant enzymes (superoxide dismutase, SOD, and catalase, CAT), along with osmolytes (proline and soluble sugars) exhibited a biphasic response, stimulated at lower doses as part of the initial protective mechanism but suppressed at higher stress levels, coinciding with photosynthetic decline. Microscopic analysis revealed alterations in root and stomatal morphology, linking structural damage with impaired translocation and nutrient balance. Arsenic accumulation in shoots increased up to 75 mg kg⁻1 but declined at 100 mg kg⁻1, indicating restricted translocation under severe stress. Integrative data analysis identified 25 mg kg⁻1 as the toxicity threshold with minimal adverse effects, and 75 mg kg⁻1 as the tolerance limit up to which plants could still cope. At 100 mg kg⁻1, the stress overwhelmed defenses, resulting in severe damage and major yield loss. These findings provide a critical benchmark for risk assessment and mitigation of As stress in wheat.
Graphical Abstract