School of Environment, Nanjing Normal University, Nanjing, 210023, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Jiangsu Engineering Lab of Water and Soil Eco-remediation, Nanjing, 210023, China.
School of Environment, Nanjing Normal University, Nanjing, 210023, China.
Environ Pollut. 2021 Jan 1;268(Pt B):115912. doi: 10.1016/j.envpol.2020.115912. Epub 2020 Nov 6.
Due to a close contact with water column, submerged macrophytes are easily disturbed by environment change in freshwater ecosystems, especially at the seedling stage. In recent decades, freshwater ecosystems have been subject to severe cadmium (Cd) pollution, which can cause toxic effects on the growth of submerged macrophytes. Moreover, the temperature rise resulting from climate warming and water level decline may further aggravate such effect, especially in shallow lakes. Here, we investigated the independent and interaction effects of Cd exposure levels (0, 0.5, 1, and 2.5 mg L) and temperature (15, 25, and 30 °C) on morphological and physiological traits of Myriophyllum aquaticum (Vell.) Verd. Seedlings generated from propagules and seeds. The temperature rise and Cd exposure generally resulted in a significant increase of Cd concentrations and antioxidant enzyme activities in leaves, as well as a decrease of chlorophyll a and b concentrations. The number and length of leaves generated from propagules always show a downward trend with the increase of Cd exposure, regardless of the temperature. Moreover, the lowest leaf number and length always occurred at high temperature (i.e. 30 °C) when the Cd exposure level increased to 1 and 2.5 mg L. For the seedlings generated from seeds, the temperature rise caused an increase of leaf emergence rate under low Cd exposure levels, but resulted in a significant decrease with the Cd exposure level. This study indicates the negative effects of Cd exposure and temperature rise on submerged macrophytes at the seedling stage, and highlights that temperature rise would enhance Cd toxicity.
由于与水柱密切接触，沉水植物很容易受到淡水生态系统中环境变化的干扰，尤其是在幼苗阶段。近几十年来，淡水生态系统受到了严重的镉（Cd）污染，这会对沉水植物的生长产生毒性作用。此外，气候变暖导致的水温升高和水位下降可能会进一步加剧这种影响，尤其是在浅水湖泊中。在这里，我们研究了 Cd 暴露水平（0、0.5、1 和 2.5 mg/L）和温度（15、25 和 30°C）对来自繁殖体和种子的菹草（Vell.）Verd.幼苗形态和生理特性的独立和交互影响。温度升高和 Cd 暴露通常会导致叶片中 Cd 浓度和抗氧化酶活性显著增加，同时叶绿素 a 和 b 浓度降低。无论温度如何，来自繁殖体的叶片数量和长度总是随着 Cd 暴露的增加而呈下降趋势。此外，当 Cd 暴露水平增加到 1 和 2.5 mg/L 时，最低的叶片数量和长度总是出现在高温（即 30°C）下。对于来自种子的幼苗，在低 Cd 暴露水平下，温度升高会导致叶片出现率增加，但随着 Cd 暴露水平的升高，叶片出现率会显著下降。本研究表明 Cd 暴露和温度升高对幼苗期沉水植物的负面影响，并强调了温度升高会增强 Cd 的毒性。
