人工湿地处理高氨氮废水中植物的耐受性

The Tolerance of Plants to High Concetration of Ammonia in Wastewater by Constructed Wetland

选择人工湿地中常用的挺水植物美人蕉和鸢尾作为受试植物,配制不同氨氮浓度的模拟废水进行培养,每隔一段停留时间测试植株生理指标,以期得到植株的氨氮耐受性特征。研究脯氨酸、丙二醛、超氧化物歧化酶、净光合速率、蒸腾速率、气孔导度等表征植株耐受性指标的变化。结果表明,美人蕉叶片中脯氨酸和丙二醛含量均随氨氮胁迫时间的延长呈现先增高后降低的趋势,说明植株对氨氮的胁迫具有一定的适应性。鸢尾叶片中两种物质的含量均明显高于美人蕉。氨氮浓度为200 mg/L时,美人蕉SOD活性变化很小,而鸢尾则呈现先增高后降低的趋势;随着氨氮浓度升高,美人蕉和鸢尾叶片的SOD活性都呈先升高后降低的趋势,但鸢尾叶片SOD活性无法恢复到初始水平,SOD系统遭到损害。低浓度氨氮对美人蕉净光合速率具有明显的促进作用,且蒸腾速率呈现先升高后下降的趋势。表明在低氨氮浓度情况下,美人蕉表现出较强的耐受性。鸢尾净光合速率和蒸腾速率均有所下降,植物生长受到抑制。研究结果表明,美人蕉对高氨氮具有更强的耐受性,是人工湿地处理高氨氮废水时较为理想的湿地植物。

Two commonly used emergent plants for constructed wetland including Canna and Iris were used to be stressed by the configuration of simulated wastewater with different concentrations of ammonia. Plant physiological indicators were determined at fixed residence time intervals to obtain ammonia tolerance characteristics of the two plants. The plant tolerance indexes were proline, malondialdehyde, superoxide dismutase, photosynthetic rate, transpiration rate and stomatal conductance. The results showed that the contents of proline and MDA in Canna increased with prolonged stress time of ammonia at first and then decreased, indicating that Canna had a certain flexibility of ammonia nitrogen. The contents of proline and MDA in Iris were significantly higher than that of Canna. SOD activity of Canna changed little when the concentration of ammonia nitrogen was 200 mg / L, while the index of Iris increased at first and then decreased. As the concentration of ammonia nitrogen increased, the SOD activity of Canna and Iris increased at first and then decreased. While the SOD activity of Iris was not able to be restored to original level, indicating that the SOD enzyme system was compromised. The photosynthetic rate of Canna was significantly promoted when the concentration of ammonia nitrogen was low. The transpiration rate increased at first and then decreased, showing that Canna had stronger tolerance than Iris had when the concentration of ammonia nitrogen was low. Canna had a stronger tolerance to high concentration of ammonia nitrogen. It was the ideal wetland plants for constructed wetland to treat high concentration of ammonia nitrogen in wastewater.