Characteristics of growth, nutrient uptake, purification effect of Ipomoea aquatica, Lolium multiflorum, and Sorghum sudanense grown under different nitrogen levels

Abstract This study aims to identify the growth, nutrient uptake, and purification efficiency of Ipomoea aquatica , Lolium multiflorum , and Sorghum sudanense under different nitrogen levels. In comparison with NH 4 + or NO 3 − as the sole N source, the relative growth rate (RGR) and biomass of three species culture in the NH 4 NO 3 solution increased significantly ( p V max ) of NH 4 + was higher than that of NO 3 − whereas the K m were slightly lower than that of NO 3 − of three species; the addition of NO 3 − to the NH 4 + solutions stimulated the NH 4 + uptake, whereas, the addition of NH 4 + to the NO 3 − solutions suppressed NO 3 − uptake of three species; L. multiflorum at the studied supply rates of nitrogen exhibited a higher uptake capacity and a lower affinity for ammonium, conforming with adaptation to a high NH 4 + nutrient levels. However, the S. sudanense has a competitive advantage over the other two species at high NO 3 − nutrient levels; the NH 4 + and NO 3 − purification efficiency had obvious changes when High-nitrogen and Low-nitrogen wastewater were treated by three species. These findings would help select a suitable species to remove contamination and improve water quality in constructed wetland treatment systems.