Differences in Nitrogen and Phosphorus Removal under Different Temperatures in Oenanthe javanica Cultivars

Plant selection plays a critical role in phytoremediation. However, previous research has focused on comparing different plant species but has ignored different cultivars. Here, a laboratory experiment was performed to analyze the nitrogen (N) and phosphorus (P) removal performance of different cultivars of Oenanthe javanica , which are widely employed for phytoremediation in China. Seven cultivars were planted on simulated livestock wastewater with high N and P content prepared with compounds for 22 days in two artificial climate chambers with different temperatures. N and P contents were monitored to estimate the nutrient removal performance of the cultivars. ‘Suzhou Yuanye’ had the highest N removal ability at room temperature (45.33 ± 1.92%) and under cold stress (39.63 ± 2.15%) in 22 days, and it could also remove P effectively (99.32 ± 0.33% at room temperature and 77.50 ± 0.08% under cold stress). ‘Yixing Yuanye’ performed the best in P removal (97.90 ± 2.89% at room temperature and 99.57 ± 0.61% under cold stress). ‘Liyang Baiqin’ performed well in N removal only at room temperature (44.30 ± 1.03%). ‘Suqian Jianye’ had low removal efficiencies for both N and P. From the biomass and N content, we could conclude that the high N removal efficiency of ‘Suzhou Yuanye’ is due to high N assimilation of the plant. However, ‘Yixing Yuanye’ did not show higher P assimilation ability than other cultivars. Taken together, the selection of cultivars is important for phytoremediation projects using O. javanica , and ‘Suzhou Yuanye’ is much more suitable for phytoremediation than other cultivars.