Wenzhou Academy of Agricultural Science, Wenzhou, 325006, China.
College of Life and Environmental Science, Wenzhou University, Wenzhou, 325035, China.
J Environ Manage. 2021 Sep 1;293:112965. doi: 10.1016/j.jenvman.2021.112965. Epub 2021 Jun 5.
Rotala rotundifolia is a novel submerged macrophyte able to survive across the winter under temperature as low as 4 °C. Dynamic nutrient removal potential of R. rotundifolia was estimated using the Eco-tank system simulating natural eutrophic waters. The growth and physiological response of R. rotundifolia by cutting and division propagation to light (100%, 60%, and 20% natural light) were investigated. The results showed that R. rotundifolia was superior in removing N and P from eutrophic waters. As influent concentrations of NH-N and total phosphorus (TP) were 4.81-5.87 and 0.61-0.78 mg L, effluent concentrations of NH-N, total nitrogen (TN), and TP were separately 0.06-1.10, 0.40-1.59, and 0.05-0.17 mg L, with removal efficiencies of 93.6%, 84.6%, and 82.5% at a flow rate of 200 L d. The growth and morphology of the plant under two propagation patterns were influenced by light and the responses were quite different. The biomass of the plant by cutting was higher at low light conditions, and the plant allocated more biomass on above ground. However, there was no significant difference in the height. By division, the plant preferred to high light. The biomass and height were significantly higher at 100% natural light. The peroxidase (POD), superoxide dismutase (SOD) and root activities of plant by cutting showed a trend of decrease and followed by an increase with light reduction, while by division, they increased with reduced light available. Variations of chlorophyll and soluble protein of the plant by cutting and division were contrary to the changes of POD activity. These results suggest that R. rotundifolia can be used to effectively remove nitrogen and phosphorus in eutrophic waters, and high light promotes the growth of the plant by division, while suitable shade is needed for the plant by cutting.
圆叶节节菜是一种新型沉水植物，能在低至 4°C 的温度下越冬。采用模拟自然富营养化水体的生态罐系统，估算了圆叶节节菜的动态营养去除潜力。通过切割和分株繁殖，研究了圆叶节节菜对光照（自然光的 100%、60%和 20%）的生长和生理响应。结果表明，圆叶节节菜对富营养化水体中的氮和磷具有较好的去除效果。当进水 NH-N 和总磷（TP）浓度分别为 4.81-5.87 和 0.61-0.78mg/L 时，出水 NH-N、总氮（TN）和 TP 浓度分别为 0.06-1.10、0.40-1.59 和 0.05-0.17mg/L，去除率分别为 93.6%、84.6%和 82.5%，流速为 200L/d。两种繁殖方式下，光照对植物的生长和形态有影响，且响应方式不同。切割繁殖的植物在低光照条件下生物量较高，地上部分分配的生物量较多。然而，高度没有显著差异。通过分株繁殖，植物更喜欢强光。在自然光 100%的条件下，生物量和高度显著增加。切割繁殖的植物的过氧化物酶（POD）、超氧化物歧化酶（SOD）和根活力均表现出随光照减少而降低，随后升高的趋势，而分株繁殖的植物则随光照减少而升高。切割和分株繁殖的植物的叶绿素和可溶性蛋白的变化与 POD 活性的变化相反。这些结果表明，圆叶节节菜可有效去除富营养化水体中的氮磷，强光促进分株繁殖植物的生长，而切割繁殖植物则需要适宜的遮荫。
