Assessment of Cyanobacteria and Tryptophan role in the Alleviation of the Toxic Action of Brominal Herbicide on Wheat Plants

Cyanobacteria like Arthrospira platensis and Nostoc muscorum are known to be beneficial for plant development. They can improve plant growth, yield, proximate content (protein and carbohydrate), and stimulate plant tolerance to abiotic stresses like herbicides. In the present study, the impacts of brominal herbicide (Bh) alone or in combination with natural cyanobacterial or synthetic tryptophan treatments were investigated on the morphological and physiological parameters of wheat plants. The Bh treatment caused a reduction in all the estimated morphological and physiological parameters of the plants. The combination of Bh and cyanobacterial or tryptophan treatments could significantly increase the plant length, fresh and dry weights, and yield parameters (spike length, spike weight, number of spikes per plant, number of grains per spike, weight of 1000 grains, and productivity). In addition, pigments, carbohydrates, and protein content was also reduced in response to the Bh treatment, while the antioxidant enzyme activity and lipid peroxidation increased. Priming wheat grains in cyanobacterial aqueous extract and tryptophan before cultivation reversed the toxic effects of Bh application, amplified extra antioxidant ability, and decreased the lipid peroxidation of the plants. Finally, the combination of cyanobacterial and tryptophan as treatments for priming wheat grains before being sown in the soil should help to strengthen the defense systems of the wheat plant to tolerate the adverse effects of species-specific Bh upon application.