不同氨氮浓度和基质条件对沉水植物的影响

Effects of Different Ammonia Nitrogen Concentrations and Substrate Conditions on Submerged Plants

在室外静态模拟条件下,通过测定黑藻、刺苦草、穗花狐尾藻的相对生长速率、分枝数、最大株高、叶绿素a、超氧化物歧化酶、过氧化物酶、过氧化氢酶的指标变化,研究沉水植物在基底和氨氮条件双因素变化下的响应情况。结果表明,黑藻、刺苦草、穗花狐尾藻的最大氨氮耐受浓度分别为2.69、4.69、2.69 mg/L。基于各沉水植物的生长速率变化情况,除黑藻在中浓度氨氮条件下生长速率不及淤泥组外,黄土组沉水植物适应氨氮胁迫的能力都更强。不同基质下同种植物在不同氨氮浓度水体中的叶绿素a含量整体呈现先升高后下降的趋势,且同一浓度下不同基质组无明显差异。同种基质条件下,黑藻和穗花狐尾藻在中浓度氨氮条件以下,SOD指标变化不显著,刺苦草呈现先上升后下降的趋势。淤泥和黄土环境下,不同氨氮浓度对黑藻CAT指标都无显著影响。

Under outdoor static simulation conditions,by measuring the relative growth rate,branch number,maximum plant height,chlorophyll a,superoxide dismutase,peroxidase and catalase of Hydrilla verticillata,Vallisneria spinulosa and Myriophyllum spicatum,we study the response of submerged plants to the changes of substrate and ammonia nitrogen conditions.The results showed that the maximum ammonia nitrogen tolerance concentrations of Hydrilla verticillata,Vallisneria spinulosa and Myriophyllum spicatum were 2.69 mg/L,4.69 mg/L and 2.69 mg/L respectively.Based on the growth rate changes of submerged plants,except that the growth rate of Hydrilla verticillata is lower than that of silt group under the condition of medium concentration of ammonia nitrogen,the submerged plants in loess group have stronger ability to adapt to ammonia nitrogen stress.The chlorophyll a content of the same plant in water with different ammonia nitrogen concentrations under different substrates showed an overall trend of increasing first and then decreasing,and there was no significant difference between different substrate groups under the same concentration.Under the same substrate environment,under the medium concentration of ammonia nitrogen,the SOD index of Hydrilla verticillata and Myriophyllum spicatum did not change significantly,while the thorn bittergrass showed a trend of rising first and then declining.In silt and loess environment,different ammonia nitrogen concentrations have no significant effect on the CAT index of Hydrilla verticillata.