Characterization of Brassica napus responses to diluted and undiluted industrial wastewater

Rising water scarcity, together with increased industrial wastewater production, suggests reusing of wastewater for plant irrigation. The wastewater from Razi petrochemical complex contained different salts and heavy metals. Variation in Brassica napus responses to wastewater irrigation has recommended appropriate levels of mineral nutrients in diluted wastewater that stimulated plant growth, and toxic levels of salts in undiluted wastewater that restricted plant growth. The undiluted wastewater irrigation significantly decreased chlorophyll fluorescence, along with photosynthetic capacity, while wastewater dilution mitigated its adverse effect. High levels of salts in undiluted wastewater induced an imbalance in plant mineral nutrients, which was evidenced with increased lipid peroxidation and reduced plant growth. On the contrary to adverse effects of undiluted wastewater on plant performance, the diluted wastewater, especially at 50% level, behaved as a fertilizer which increased leaf mineral nutrients, photosynthetic capacity, morphological and anatomical features of plant, but decreased lipid peroxidation. In relation to improvement in photosynthetic capacity, a significant increase was achieved in stomatal traits in plants irrigated with half-strength wastewater. In conclusion, due to the nutrition values of wastewater, it can be suggested to irrigate plants with diluted wastewater with the aim of improving crop productivity and saving freshwater sources.