Ameliorative Role of Poultry Manure and Exogenous Abscisic Acid in Mitigating Cadmium Toxicity in Wheat (Triticum aestivum L.)

Abstract

Cadmium (Cd) contamination is one of the most important environmental problems which has a negative impact on wheat (Triticum aestivum L.) development, physiology and yield formation. To assess the ability of poultry manure (PM) and exogenous application of abscisic acid (ABA) to reduce Cd stress in wheat, a pot experiment was conducted. The experiment included seven treatments: T1, untreated control; T2, Cd stress; T3, PM (1%); T4, ABA (10 µM); T5, Cd + PM; T6, Cd + ABA; and T7, Cd + PM + ABA. It was observed that hydrogen peroxide (H₂O₂) content was increased by Cd stress in the plants to about 118 µM g⁻¹ FW (fresh weight) while in the control plants it was 42 µM g⁻¹ FW, which is about 181% of the control. The concentration of malondialdehyde (MDA) rose from about 16 to 27 µM g-1 FW. Cadmium exposure also caused a decrease in tiller number (from about 5.2 to 3.6 tiller/plant), spike length (from 8.2 to 5.7 cm), spikelets per spike (from 12.5 to 8.7 spikelets/spike) and grains per spike (from 10.2 to 7.1 grains/spike). In combined treatments (Cd + PM + ABA), the decrease in concentration was observed for H₂O₂ to ~ 90 µM g⁻¹ FW and for MDA to ~ 17 µM g⁻¹ FW. Tiller number, spike length and spikelets per spike were increased to ~ 4.7, 7.5 cm, and 11.3, respectively, while the number of grains per spike was not as improved and was ~ 9.3. These results showed that PM and ABA were partially able to reduce Cd-induced oxidative stress and enhanced yield-related traits in wheat. Further research is needed to evaluate soil Cd availability, grain accumulation of Cd, activities of antioxidant enzymes, and final grain yield, to verify treatment effectiveness and food-safety implications.